SPACE
Astrophysicists confirm the faintest galaxy ever seen in the early universe
The small, distant galaxy JD1 is typical of the kind that burned through hydrogen left over from the Big Bang
Peer-Reviewed PublicationIMAGE: A PROJECTED IMAGE OF THE GALAXY JD1 (INSET), WHICH IS LOCATED BEHIND A BRIGHT CLUSTER GALAXY CALLED ABELL2744. view more
CREDIT: GUIDO ROBERTS-BORSANI/UCLA); ORIGINAL IMAGES: NASA, ESA, CSA, SWINBURNE UNIVERSITY OF TECHNOLOGY, UNIVERSITY OF PITTSBURGH, STSCI
Key takeaways
- After the Big Bang, the universe expanded and cooled sufficiently for hydrogen atoms to form. In the absence of light from the first stars and galaxies, the universe entered a period known as the cosmic dark ages.
- The first stars and galaxies appeared several hundred million years later and began burning away the hydrogen fog left over from the Big Bang, rendering the universe transparent, like it is today.
- Researchers led by astrophysicists from UCLA confirmed the existence of a distant, faint galaxy typical of those whose light burned through the hydrogen atoms; the finding should help them understand how the cosmic dark ages ended.
An international research team led by UCLA astrophysicists has confirmed the existence of the faintest galaxy ever seen in the early universe. The galaxy, called JD1, is one of the most distant identified to date, and it is typical of the kinds of galaxies that burned through the fog of hydrogen atoms left over from the Big Bang, letting light shine through the universe and shaping it into what exists today.
The discovery was made using NASA’s James Webb Space Telescope, and the findings are published in the journal Nature.
The first billion years of the universe’s life were a crucial period in its evolution. After the Big Bang, approximately 13.8 billion years ago, the universe expanded and cooled sufficiently for hydrogen atoms to form. Hydrogen atoms absorb ultraviolet photons from young stars; however, until the birth of the first stars and galaxies, the universe became dark and entered a period known as the cosmic dark ages. The appearance of the first stars and galaxies a few hundred million years later bathed the universe in energetic ultraviolet light which began burning, or ionizing, the hydrogen fog. That, in turn, enabled photons to travel through space, rendering the universe transparent.
Determining the types of galaxies that dominated that era — dubbed the Epoch of Reionization — is a major goal in astronomy today, but until the development of the Webb telescope, scientists lacked the sensitive infrared instruments required to study the first generation of galaxies.
“Most of the galaxies found with JWST so far are bright galaxies that are rare and not thought to be particularly representative of the young galaxies that populated the early universe,” said Guido Roberts-Borsani, a UCLA postdoctoral researcher and the study’s first author. “As such, while important, they are not thought to be the main agents that burned through all of that hydrogen fog.
“Ultra-faint galaxies such as JD1, on the other hand, are far more numerous, which is why we believe they are more representative of the galaxies that conducted the reionization process, allowing ultraviolet light to travel unimpeded through space and time.”
JD1 is so dim and so far away that it is challenging to study without a powerful telescope — and a helping hand from nature. JD1 is located behind a large cluster of nearby galaxies, called Abell 2744, whose combined gravitational strength bends and amplifies the light from JD1, making it appear larger and 13 times brighter than it otherwise would. The effect, known as gravitational lensing, is similar to how a magnifying glass distorts and amplifies light within its field of view; without gravitational lensing, JD1 would likely have been missed.
The researchers used the Webb Telescope’s near-infrared spectrograph instrument, NIRSpec, to obtain an infrared light spectrum of the galaxy, allowing them to determine its precise age and its distance from Earth, as well as the number of stars and amount of dust and heavy elements that it formed in its relatively short lifetime.
The combination of the galaxy’s gravitational magnification and new images from another one of the Webb Telescope’s near-infrared instruments, NIRCam, also made it possible for the team to study the galaxy’s structure in unprecedented detail and resolution, revealing three main elongated clumps of dust and gas that are forming stars. The team used the new data to trace JD1’s light back to its original source and shape, revealing a compact galaxy just a fraction of the size of older galaxies like the Milky Way, which is 13.6 billion years old.
Because light takes time to travel to Earth, JD1 is seen as it was approximately 13.3 billion years ago, when the universe was only about 4% of its present age.
“Before the Webb telescope switched on, just a year ago, we could not even dream of confirming such a faint galaxy,” said Tommaso Treu, a UCLA physics and astronomy professor, and the study’s second author. “The combination of JWST and the magnifying power of gravitational lensing is a revolution. We are rewriting the book on how galaxies formed and evolved in the immediate aftermath of the Big Bang.”
JOURNAL
Nature
Eventually everything will evaporate, not only black holes
New theoretical research by Michael Wondrak, Walter van Suijlekom and Heino Falcke of Radboud University has shown that Stephen Hawking was right about black holes, although not completely. Due to Hawking radiation, black holes will eventually evaporate, but the event horizon is not as crucial as had been believed. Gravity and the curvature of spacetime cause this radiation too. This means that all large objects in the universe, like the remnants of stars, will eventually evaporate.
Using a clever combination of quantum physics and Einstein’s theory of gravity, Stephen Hawking argued that the spontaneous creation and annihilation of pairs of particles must occur near the event horizon (the point beyond which there is no escape from the gravitational force of a black hole). A particle and its anti-particle are created very briefly from the quantum field, after which they immediately annihilate. But sometimes a particle falls into the black hole, and then the other particle can escape: Hawking radiation. According to Hawking, this would eventually result in the evaporation of black holes.
Spiral
In this new study the researchers at Radboud University revisited this process and investigated whether or not the presence of an event horizon is indeed crucial. They combined techniques from physics, astronomy and mathematics to examine what happens if such pairs of particles are created in the surroundings of black holes. The study showed that new particles can also be created far beyond this horizon. Michael Wondrak: ‘We demonstrate that, in addition to the well-known Hawking radiation, there is also a new form of radiation.’
Everything evaporates
Van Suijlekom: ‘We show that far beyond a black hole the curvature of spacetime plays a big role in creating radiation. The particles are already separated there by the tidal forces of the gravitational field.’ Whereas it was previously thought that no radiation was possible without the event horizon, this study shows that this horizon is not necessary.
Falcke: ‘That means that objects without an event horizon, such as the remnants of dead stars and other large objects in the universe, also have this sort of radiation. And, after a very long period, that would lead to everything in the universe eventually evaporating, just like black holes. This changes not only our understanding of Hawking radiation but also our view of the universe and its future.’
The study was published on 2 June in the leading journal “Physical Review Letters” of the American Physical Society (APS). Michael Wondrak is excellence fellow at Radboud University and an expert in quantum field theory. Walter van Suijlekom is a Professor of Mathematics at Radboud University and works on the mathematical formulation of physics problems. Heino Falcke is an award-winning Professor of Radio Astronomy and Astroparticle Physics at Radboud University and known for his work on predicting and making the first picture of a black hole.
JOURNAL
Physical Review
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Gravitational Pair Production and Black Hole Evaporation
ARTICLE PUBLICATION DATE
2-Jun-2023
Mysterious dashes revealed in Milky Way’s center
Hundreds of horizontal filaments point toward our central supermassive black hole
Peer-Reviewed PublicationIMAGE: MEERKAT IMAGE OF THE GALACTIC CENTER WITH COLOR-CODED POSITION ANGLES OF ALL FILAMENTS. view more
CREDIT: FARHAD YUSEF-ZADEH/NORTHWESTERN UNIVERSI
- New radio telescope images reveal hundreds of filaments along the galactic plane, each measuring 5 to 10 light-years in length
- These structures likely originated a few million years ago when outflow from our supermassive black hole interacted with surrounding materials
- Researcher: ‘I was actually stunned when I saw these’
EVANSTON, Ill. — An international team of astrophysicists has discovered something wholly new, hidden in the center of the Milky Way galaxy.
In the early 1980s, Northwestern University’s Farhad Yusef-Zadeh discovered gigantic, one-dimensional filaments dangling vertically near Sagittarius A*, our galaxy’s central supermassive black hole. Now, Yusef-Zadeh and his collaborators have discovered a new population of filaments — but these threads are much shorter and lie horizontally or radially, spreading out like spokes on a wheel from the black hole.
Although the two populations of filaments share several similarities, Yusef-Zadeh assumes they have different origins. While the vertical filaments sweep through the galaxy, towering up to 150 light-years high, the horizontal filaments look more like the dots and dashes of Morse code, punctuating only one side of Sagittarius A*.
The study will be published on Friday (June 2) in The Astrophysical Journal Letters.
“It was a surprise to suddenly find a new population of structures that seem to be pointing in the direction of the black hole,” Yusef-Zadeh said. “I was actually stunned when I saw these. We had to do a lot of work to establish that we weren’t fooling ourselves. And we found that these filaments are not random but appear to be tied to the outflow of our black hole. By studying them, we could learn more about the black hole’s spin and accretion disk orientation. It is satisfying when one finds order in a middle of a chaotic field of the nucleus of our galaxy.”
An expert in radio astronomy, Yusef-Zadeh is a professor of physics and astronomy at Northwestern’s Weinberg College of Arts and Sciences and member of CIERA.
Decades in the making
The new discovery may come as a surprise, but Yusef-Zadeh is no stranger to uncovering mysteries at the center of our galaxy, located 25,000 light-years from Earth. The latest study builds on four decades of his research. After first discovering the vertical filaments in 1984 with Mark Morris and Don Chance, Yusef-Zadeh along with Ian Heywood and their collaborators later uncovered two gigantic radio-emitting bubbles near Sagittarius A*. Then, in a series of publications in 2022, Yusef-Zadeh (in collaborations with Heywood, Richard Arent and Mark Wardle) revealed nearly 1,000 vertical filaments, which appeared in pairs and clusters, often stacked equally spaced or side by side like strings on a harp.
Yusef-Zadeh credits the flood of new discoveries to enhanced radio astronomy technology, particularly the South African Radio Astronomy Observatory’s (SARAO) MeerKAT telescope. To pinpoint the filaments, Yusef-Zadeh’s team used a technique to remove the background and smooth the noise from MeerKAT images in order to isolate the filaments from surrounding structures.
“The new MeerKAT observations have been a game changer,” he said. “The advancement of technology and dedicated observing time have given us new information. It’s really a technical achievement from radio astronomers.”
Horizontal vs. vertical
After studying the vertical filaments for decades, Yusef-Zadeh was shocked to uncover their horizontal counterparts, which he estimates are about 6 million years old. “We have always been thinking about vertical filaments and their origin,” he said. “I’m used to them being vertical. I never considered there might be others along the plane.”
While both populations comprise one-dimensional filaments that can be viewed with radio waves and appear to be tied to activities in the galactic center, the similarities end there.
The vertical filaments are perpendicular to the galactic plane; the horizontal filaments are parallel to the plane but point radially toward the center of the galaxy where the black hole lies. The vertical filaments are magnetic and relativistic; the horizontal filaments appear to emit thermal radiation. The vertical filaments encompass particles moving at speeds near the speed of light; the horizontal filaments appear to accelerate thermal material in a molecular cloud. There are several hundred vertical filaments and just a few hundred horizontal filaments. And the vertical filaments, which measure up to 150 light-years high, far surpass the size of the horizontal filaments, which measure just 5 to 10 light-years in length. The vertical filaments also adorn space around the nucleus of the galaxy; the horizontal filaments appear to spread out to only one side, pointing toward the black hole.
“One of the most important implications of radial outflow that we have detected is the orientation of the accretion disk and the jet-driven outflow from Sagittarius A* along the galactic plane,” Yusef-Zadeh said.
‘Our work is never complete’
The new discovery is filled with unknowns, and Yusef-Zadeh’s work to unravel its mysteries has just begun. For now, he can only consider a plausible explanation about the new population’s mechanisms and origins.
“We think they must have originated with some kind of outflow from an activity that happened a few million years ago,” Yusef-Zadeh said. “It seems to be the result of an interaction of that outflowing material with objects near it. Our work is never complete. We always need to make new observations and continually challenge our ideas and tighten up our analysis.”
The study, “The population of the galactic center filaments: Position angle distribution reveal a degree-scale collimated outflow from Sgr A* along the galactic plane,” was supported by NASA (award number 80GSFC21M0002). The SARAO is a facility of the National Research Foundation, an agency of the Department of Science and Innovation.
MeerKAT image of the galactic center with color-coded position angles of the long, vertical filaments.
A SCHEMATIC DIAGRAM OF THE OUTFLOW FROM SAGITTARIUS A*, THE MILKY WAY'S CENTRAL SUPERMASSIVE BLACK HOLE.
CREDIT
FARHAD YUSEF-ZADEH/NORTHWESTERN UNIVERSITYJOURNAL
The Astrophysical Journal Letters
METHOD OF RESEARCH
Observational study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
The Population of the Galactic Center Filaments: Position Angle Distribution Reveal a Degree-scale Collimated Outflow from Sgr A* along the Galactic Plane
ARTICLE PUBLICATION DATE
2-Jun-2023
Webb Telescope finds towering plume of water escaping from Saturn moon
SwRI scientist awarded JWST Cycle 2 observations of Enceladus
Peer-Reviewed PublicationIMAGE: SWRI CONTRIBUTED TO NEW CYCLE 1 JWST FINDINGS THAT SHOW THE PLUME OF WATER ESCAPING FROM SATURN’S MOON ENCELADUS EXTENDS 6,000 MILES OR MORE THAN 40 TIMES THE MOON’S SIZE. IN LIGHT OF THIS DISCOVERY, SWRI’S DR. CHRISTOPHER GLEIN WAS AWARDED A NASA JWST CYCLE 2 ALLOCATION TO STUDY THE PLUME AS WELL AS THE ICY SURFACE OF ENCELADUS, TO BETTER UNDERSTAND THE POTENTIAL HABITABILITY OF THIS OCEAN WORLD. view more
CREDIT: NASA/ESA/CSA/ALYSSA PAGAN (STSCI)/GERONIMO VILLANUEVA (NASA-GSFC)
Two Southwest Research Institute scientists were part of a James Webb Space Telescope (JWST) team that observed a towering plume of water vapor more than 6,000 miles long — roughly the distance from the U.S. to Japan — spewing from the surface of Saturn’s moon, Enceladus. In light of this NASA JWST Cycle 1 discovery, SwRI’s Dr. Christopher Glein also received a Cycle 2 allocation to study the plume as well as key chemical compounds on the surface, to better understand the potential habitability of this ocean world.
During its 13-year reconnaissance of the Saturn system, the Cassini spacecraft discovered that Enceladus has a subsurface ocean of liquid water, and Cassini analyzed samples as plumes of ice grains and water vapor erupted into space from cracks in the moon’s icy surface.
“Enceladus is one of the most dynamic objects in the solar system and is a prime target in humanity’s search for life beyond Earth,” said Glein, a leading expert in extraterrestrial oceanography. He is a co-author of a paper recently accepted by Nature Astronomy. “In the years since NASA’s Cassini spacecraft first looked at Enceladus, we never cease to be amazed by what we find is happening on this extraordinary moon.”
Once again, the latest observations made with Webb’s Near InfraRed Spectrograph have yielded remarkable results.
“When I was looking at the data, at first, I was thinking I had to be wrong, it was just so shocking to map a plume more than 20 times the diameter of the moon,” said Geronimo Villanueva of NASA’s Goddard Space Flight Center and lead author of the recent paper. “The plume extends far beyond what we could have imagined.”
Webb’s sensitivity reveals a new story about Enceladus and how it feeds the water supply for the entire system of Saturn and its rings. As Enceladus whips around the gas giant in just 33 hours, the moon spews water, leaving a halo, almost like a donut, in its wake. The plume is not only huge, but the water spreads across Saturn’s dense E-ring. JWST data indicate that roughly 30 percent of the water stays in the moon’s wake, while the other 70 percent escapes to supply the rest of the Saturnian system.
“The Webb observations, for the first time, are visually illustrating how the moon's water vapor plumes are playing a role in the formation of the torus,” said SwRI’s Dr. Silvia Protopapa, an expert in the compositional analysis of icy bodies in the solar system who was also on the Cycle 1 team. “This serves as a stunning testament to Webb's extraordinary abilities. I'm thrilled to be part of the Cycle 2 team as we initiate our search for new indications of habitability and plume activity on Enceladus.”
Spurred by the incredible findings from Webb’s first fleeting glimpse of Enceladus, Glein is leading the same team that will observe Enceladus again with JWST in the next year.
“We will search for specific indicators of habitability, such as organic signatures and hydrogen peroxide,” Glein said. “Hydrogen peroxide is particularly interesting because it can provide much more potent sources of metabolic energy than what we previously identified. Cassini didn't give us a clear answer on the availability of such strong oxidants on Enceladus.”
The new observations will provide the best remote opportunity to search for habitability indicators on the surface, by boosting the signal-to-noise ratio by up to a factor of 10 compared with Cycle 1. Understanding the time variability of plume outgassing is also important to plan for future planetary science missions that target the plume.
“Webb can serve as a bridge between Cassini and the proposed search-for-life mission, Orbilander,” Glein said. “After Cycle 2, we will have a better idea if ocean samples are widely distributed over Enceladus’s surface, as opposed to just near the south pole. These next observations could help us determine if Orbilander can access ocean samples near the equator, which may help us get back to Enceladus sooner.”
The James Webb Space Telescope is the world's premier space science observatory. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency). The team’s results were accepted for publication on May 17, 2023, in Nature Astronomy, and a pre-print pdf is available at https://psg.gsfc.nasa.gov/apps/Enceladus_JWST.pdf.
JOURNAL
Nature Astronomy
METHOD OF RESEARCH
Observational study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
JWST molecular mapping and characterization of Enceladus’ water plume feeding its torus
A telescope’s last view
Astronomers discover the last three planets the Kepler telescope observed before going dark.
Peer-Reviewed PublicationIMAGE: WITH THE HELP OF CITIZEN SCIENTISTS, ASTRONOMERS DISCOVERED WHAT MAY BE THE LAST THREE PLANETS THAT THE KEPLER SPACE TELESCOPE SAW BEFORE IT WAS RETIRED. THIS ILLUSTRATION DEPICTS NASA’S KEPLER SPACE TELESCOPE, WHICH RETIRED IN OCTOBER 2018, AND THREE PLANETS DISCOVERED IN ITS FINAL DAYS OF DATA. view more
CREDIT: NASA’S JET PROPULSION LABORATORY
More than 5,000 planets are confirmed to exist beyond our solar system. Over half were discovered by NASA’s Kepler Space Telescope, a resilient observatory that far outlasted its original planned mission. Over nine and a half years, the spacecraft trailed the Earth, scanning the skies for periodic dips in starlight that could signal the presence of a planet crossing in front of its star.
In its last days, the telescope kept recording the brightness of stars as it was running out of fuel. On Oct. 30, 2018, its fuel tanks depleted, the spacecraft was officially retired.
Now, astronomers at MIT and the University of Wisconsin at Madison, with the help of citizen scientists, have discovered what may be the last planets that Kepler gazed upon before going dark.
The team combed through the telescope’s last week of high-quality data and spotted three stars, in the same part of the sky, that appeared to dim briefly. The scientists determined that two of the stars each host a planet, while the third hosts a planet “candidate” that has yet to be verified.
The two validated planets are K2-416 b, a planet that is about 2.6 times the size of the Earth and that orbits its star about every 13 days, and K2-417 b, a slightly larger planet that is just over three times Earth’s size and that circles its star every 6.5 days. For their size and proximity to their stars, both planets are considered “hot mini-Neptunes .” They are located about 400 light years from Earth.
The planet candidate is EPIC 246251988 b — the largest of the three worlds at almost four times the size of the Earth. This Neptune-sized candidate orbits its star in around 10 days, and is slightly farther away, 1,200 light years from Earth.
“We have found what are probably the last planets ever discovered by Kepler, in data taken while the spacecraft was literally running on fumes,” says Andrew Vanderburg, assistant professor of physics in MIT’s Kavli Institute for Astrophysics and Space Research. “The planets themselves are not particularly unusual, but their atypical discovery and historical importance makes them interesting.”
The team has published their discovery today in the journal Monthly Notices of the Royal Astronomical Society. Vanderburg’s co-authors are lead author Elyse Incha, at the University of Wisconsin at Madison, and amateur astronomers Tom Jacobs and Daryll LaCourse, along with scientists at NASA, the Center for Astrophysics of Harvard and the Smithsonian, and the University of North Carolina at Chapel Hill.
Data squeeze
In 2009, NASA launched the Kepler telescope into space, where it followed the Earth’s orbit and continuously monitored millions of stars in a patch of the northern sky. Over four years, the telescope recorded the brightness of over 150,000 stars, which astronomers used to discover thousands of possible planets beyond our solar system.
Kepler kept observing beyond its original three-and-a-half-year mission, until May 2013, when the second of four reaction wheels failed. The wheels served as the spacecraft’s gyroscopes, helping to keep the telescope pointed at a particular point in the sky. Kepler’s observations were put on pause while scientists searched for a fix.
One year later, Kepler restarted as “K2,” a reworked mission that used the sun’s wind to balance the unsteady spacecraftin a way that kept the telescope relatively stable for a few months at a time — a period called a campaign. K2 went on for another four years, observing over half a million more stars before the spacecraft finally ran out of fuel during its 19th campaign. The data from this last campaign comprised only a week of high-quality observations and another 10 days of noisier measurements as the spacecraft rapidly lost fuel.
“We were curious to see whether we could get anything useful out of this short dataset,” Vanderburg says. “We tried to see what last information we could squeeze out of it.”
By eye
Vanderburg and Incha presented the challenge to the Visual Survey Group, a team of amateur and professional astronomers who hunt for exoplanets in satellite data. They search by eye through thousands of recorded light curves of each star, looking for characteristic dips in brightness that signal a “transit,” or the possible crossing of a planet in front of its star.
The citizen scientists are especially suited to combing through short datasets such as K2’s very last campaign.
“They can distinguish transits from other wacky things like a glitch in the instrument,” Vanderburg says. “That’s helpful especially when your data quality begins to suffer, like it did in K2’s last bit of data.”
The astronomers spent a few days efficiently looking through the light curves that Kepler recorded from about 33,000 stars. The team worked with only a week’s worth of high-quality data from the telescope before it began to lose fuel and focus. Even in this short window of data, the team was able to spot a single transit in three different stars.
Incha and Vanderburg then looked at the telescope’s very last, lower-quality observations, taken in its last 11 days of operation, to see if they could spot any additional transits in the same three stars — evidence that a planet was periodically circling its star.
During this 11-day period, as the spacecraft was losing fuel, its thrusters fired more erratically, causing the telescope’s view to drift. In their analysis, the team focused on the region of each star’s light curves between thruster activity, to see if they could spot any additional transits in these less data-noisy moments.
This search revealed a second transit for K2-416 b and K2-417 b, validating that they each host a planet. The team also detected a similar dip in brightness for K2-417 b in data taken of the same star by NASA’s Transiting Exoplanet Survey Satellite (TESS), a mission that is led and operated by MIT. Data from TESS helped to confirm the planet candidate around this star.
“Those two are pretty much, without a doubt, planets,” Incha says. “We also followed up with ground-based observations to rule out all kinds of false positive scenarios for them, including background star interference, and close-in stellar binaries.”
“These are the last chronologically observed planets by Kepler, but every bit of the telescope’s data is incredibly useful,” Incha says. “We want to make sure none of that data goes to waste, because there are still a lot of discoveries to be made.”
This research was supported, in part, by MIT, NASA, and the University of Wisconsin Undergraduate Academic Awards.
###
Written by Jennufer Chu, MIT News Office
Paper: “Kepler’s Last Planet Discoveries: Two New Planets and One Single-Transit Candidate from K2 Campaign 19”
https://academic.oup.com/mnras/article-lookup/doi/10.1093/mnras/stad1049
JOURNAL
Monthly Notices of the Royal Astronomical Society
Monthly Notices of the Royal Astronomical Society
DOI
ARTICLE TITLE
“Kepler’s Last Planet Discoveries: Two New Planets and One Single-Transit Candidate from K2 Campaign 19”
“Kepler’s Last Planet Discoveries: Two New Planets and One Single-Transit Candidate from K2 Campaign 19”
Astronomers discover planets in NASA Kepler's final days of observations
IMAGE: THE FINAL OBSERVING CAMPAIGN OF NASA'S KEPLER SPACE TELESCOPE LASTED ONLY A MONTH. AS THE SPACECRAFT BEGAN TO RUN LOW ON ATTITUDE CONTROL FUEL, IT COULDN’T MAINTAIN ITS POSITION LONG ENOUGH TO COLLECT USEFUL OBSERVATIONS. IN THE END, ASTRONOMERS ONLY HAD ABOUT SEVEN DAYS OF HIGH-QUALITY DATA. A RESEARCH TEAM WORKED WITH A GROUP OF CITIZEN SCIENTISTS AND PROFESSIONAL ASTRONOMERS AND FOUND THREE PLANETS IN THE LAST BIT OF DATA. view more
CREDIT: NASA/JPL-CALTECH (K. WALBOLT)
A team of astrophysicists and citizen scientists have identified what may be some of the last planets NASA’s retired Kepler space telescope observed during its nearly decade-long mission.
The trio of exoplanets – worlds beyond our solar system – are all between the size of Earth and Neptune and closely orbit their stars.
''These are fairly average planets in the grand scheme of Kepler observations,” said Elyse Incha, a senior at the University of Wisconsin-Madison. “But they’re exciting because Kepler observed them during its last few days of operations. It showcases just how good Kepler was at planet hunting, even at the end of its life.”
A paper about the planetary trio led by Incha was published in the May 30, 2023 issue of the journal Monthly Notices of the Royal Astronomical Society.
Kepler launched in March 2009. The mission’s initial goal was to continuously monitor a patch of sky in the northern constellations Cygnus and Lyra. This long period of observations allowed the satellite to track changes in stellar brightness caused by planets crossing in front of their stars, events called transits.
After four years, the telescope had observed over 150,000 stars and identified thousands of potential exoplanets. It was the first NASA mission to find an Earth-size world orbiting within its star’s habitable zone, the range of distances where liquid water could exist on a planet’s surface.
In 2014, the spacecraft experienced mechanical issues that temporarily halted observations. The Kepler team devised a fix that allowed it to resume operations, switching its field of view roughly every three months, a period called a campaign. This renewed mission, called K2, lasted another four years and surveyed over 500,000 stars.
When Kepler was retired in October 2018, it had aided the discovery of over 2,600 confirmed exoplanets and many more candidates.
K2’s final campaign, number 19, lasted only a month. As the spacecraft began to run low on attitude control fuel, it couldn’t maintain its position long enough to collect useful observations. In the end, astronomers only had about seven days of high-quality data from Campaign 19.
Incha and her team worked with the Visual Survey Group, a collaboration between citizen scientists and professional astronomers, to scan this dataset for exoplanets. The citizen scientists hunted for signals of transiting worlds over all Campaign 19’s light curves, which record how monitored stars brightened or dimmed.
“People doing visual surveys – looking over the data by eye – can spot novel patterns in the light curves and find single objects that are hard for automated searches to detect. And even we can’t catch them all,” said Tom Jacobs, a former U.S. Navy officer and Visual Survey Group team member. “I have visually surveyed the complete K2 observations three times, and there are still discoveries waiting to be found.”
Jacobs and others found one transit for each of the three planet candidates, each orbiting a different star, in the high-quality dataset.
After their initial discovery, Incha and her team also went back and looked at the lower-quality data from the rest of Campaign 19 and found one additional transit each from two of the three stars flagged in the visual search.
“The second transits for those two planet candidates helped us confirm their discovery,” said Andrew Vanderburg, an assistant professor of physics at the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MIT) in Cambridge. “No one had found planets in this dataset before, but our collaboration was able to find three. And we’re really pushing up against the last few days, the last few minutes, of observations Kepler collected.”
Using the transit information, Incha and her team calculated the worlds’ potential sizes and orbital periods. The smallest planet, K2-416 b, is about 2.6 times Earth’s size and orbits its red dwarf star about every 13 days. K2-417 b, just over three times Earth’s size, also orbits a red dwarf star but completes an orbit every 6.5 days. The final, unconfirmed planet, EPIC 246251988 b, is almost four times Earth’s size and orbits its Sun-like star in around 10 days. (The first two planets take their name from the K2 era of the mission, the last from the Ecliptic Plane Input Catalog (EPIC) of stars in the K2 fields.)
NASA’s Transiting Exoplanet Survey Satellite (TESS), which launched in April 2018, also uses the transit method, surveying large swaths of sky at a time. During August and September 2021, TESS observed the patch of space containing the three new Kepler planets. Astronomers were able to detect two more potential transits for K2-417 b.
“In many ways, Kepler passed the planet-hunting torch to TESS,” said Knicole Colón, the TESS project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who worked on the Kepler mission for several years. “Kepler’s dataset continues to be a treasure trove for astronomers, and TESS helps give us new insights into its discoveries.”
NASA's Ames Research Center in California's Silicon Valley managed the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation in Boulder, Colorado, operated the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.
TESS is a NASA Astrophysics Explorer mission led and operated by MIT and managed by Goddard. Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA Ames; the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts; MIT’s Lincoln Laboratory; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes, and observatories worldwide are participants in the mission.
JOURNAL
Monthly Notices of the Royal Astronomical Society
ARTICLE TITLE
Kepler’s last planet discoveries: two new planets and one single-transit candidate from K2 campaign 19
ARTICLE PUBLICATION DATE
30-May-2023
Quest for alien signals in the heart of the Milky Way takes off
If an alien civilization wanted to communicate with other civilizations throughout the Milky Way, the galaxy’s core holds potential as a strategic site for a beacon
Peer-Reviewed PublicationIMAGE: ARTIST RENDITION view more
CREDIT: BREAKTHROUGH LISTEN / DANIELLE FUTSELAAR
May 30, 2023, Mountain View, CA – Akshay Suresh, a graduate student at Cornell University, spearheads an extraordinary scientific endeavor -- a groundbreaking mission to uncover periodic signals emanating from the core of the Milky Way called the Breakthrough Listen Investigation for Periodic Spectral Signals (BLIPSS). Such repetitive patterns could be the key to unlocking the mysteries of extraterrestrial intelligence in our galaxy. Suresh and his co-authors detail the project’s results thus far in a paper accepted for publication in the Astronomical Journal, “A 4–8 GHz Galactic Center Search for Periodic Technosignatures.”
BLIPSS is a collaboration between Cornell University, the SETI Institute, and Breakthrough Listen. By directing their focus towards the central region of the Milky Way, with its dense congregation of stars and possibly habitable exoplanets, the BLIPSS team amplifies the odds of capturing compelling evidence of extraterrestrial technology. If an alien civilization wanted to communicate with other civilizations throughout the Milky Way, the galaxy’s core holds potential as a strategic site for a beacon.
“BLIPSS showcases the cutting-edge potential of software as a science multiplier for SETI,” said Suresh.
SETI Institute Astronomer Dr. Vishal Gajjar is one of Suresh’s advisors on the project. “Until now, radio SETI has primarily dedicated its efforts to the search for continuous signals,” said Gajjar. “Our study sheds light on the remarkable energy efficiency of a train of pulses as a means of interstellar communication across vast distances. Notably, this study marks the first-ever comprehensive endeavor to conduct in-depth searches for these signals.”
The team began by testing their algorithm on known pulsars, successfully detecting the expected periodic emissions. Subsequently, they turned their attention to a dataset of scans of the Galactic Center captured by the Breakthrough Listen instrument on the Green Bank Telescope (GBT) in West Virginia. Unlike pulsars, which emit signals across a broad range of radio frequencies, BLIPSS narrowed its search to repeating signals within a narrower frequency range—covering less than a tenth of the width of an average FM radio station.
Dr. Steve Croft, the Breakthrough Listen Project Scientist for GBT and Adjunct Senior Astronomer at the SETI Institute, highlighted the significance of this approach, as it combines narrow bandwidths with periodic patterns that could signify deliberate technological activities by intelligent civilizations. Suresh’s technique presents a novel methodology to sift through this metaphorical haystack, enabling the team to identify tantalizing evidence of advanced extraterrestrial life forms.
A PDF of the paper (accepted for publication in the Astronomical Journal), links to the datasets examined, and an artist’s conception of an artificial periodic transmitter are available at https://seti.berkeley.edu/blipss/.
About the SETI Institute
Founded in 1984, the SETI Institute is a non-profit, multi-disciplinary research and education organization whose mission is to lead humanity’s quest to understand the origins and prevalence of life and intelligence in the Universe and to share that knowledge with the world. Its research encompasses the physical and biological sciences and leverages expertise in data analytics, machine learning and advanced signal detection technologies. The SETI Institute is a distinguished research partner for industry, academia and government agencies, including NASA and NSF.
Contact information
Rebecca McDonald
Director of Communications
SETI Institute
rmcdonald@seti.org
Breakthrough Listen is a scientific program searching for evidence of technological life in the Universe. It aims to survey one million nearby stars, the entire galactic plane and 100 nearby galaxies at a wide range of radio and optical bands. Additional information: breakthroughinitiatives.org.
The Breakthrough Initiatives are a suite of scientific and technological programs investigating the fundamental questions of life in the Universe. The Breakthrough Initiatives are funded by the Breakthrough Foundation established by Yuri and Julia Milner. Additional information about Yuri: yurimilner.com.
JOURNAL
The Astronomical Journal
ARTICLE TITLE
A 4–8 GHz Galactic Center Search for Periodic Technosignatures
ARTICLE PUBLICATION DATE
30-May-2023
One-third of galaxy’s most common planets could be in habitable zone
Our familiar, warm, yellow sun is a relative rarity in the Milky Way. By far the most common stars are considerably smaller and cooler, sporting just half the mass of our sun at most. Billions of planets orbit these common dwarf stars in our galaxy.
To capture enough warmth to be habitable, these planets would need to huddle very close to their small stars, which leaves them susceptible to extreme tidal forces.
In a new analysis based on the latest telescope data, University of Florida astronomers have discovered that two-thirds of the planets around these ubiquitous small stars could be roasted by these tidal extremes, sterilizing them. But that leaves one-third of the planets – hundreds of millions across the galaxy – that could be in a goldilocks orbit close enough, and gentle enough, to hold onto liquid water and possibly harbor life.
UF astronomy professor Sarah Ballard and doctoral student Sheila Sagear published their findings the week of May 29 in the Proceedings of the National Academy of Sciences. Ballard and Sagear have long studied exoplanets, those worlds that orbit stars other than the sun.
“I think this result is really important for the next decade of exoplanet research, because eyes are shifting toward this population of stars,” Sagear said. “These stars are excellent targets to look for small planets in an orbit where it’s conceivable that water might be liquid and therefore the planet might be habitable.”
Sagear and Ballard measured the eccentricity of a sample of more than 150 planets around these M dwarf stars, which are about the size of Jupiter. The more oval shaped an orbit, the more eccentric it is. If a planet orbits close enough to its star, at about the distance that Mercury orbits the sun, an eccentric orbit can subject it to a process known as tidal heating. As the planet is stretched and deformed by changing gravitational forces on its irregular orbit, friction heats it up. At the extreme end, this could bake the planet, removing all chance for liquid water.
“It’s only for these small stars that the zone of habitability is close enough for these tidal forces to be relevant,” Ballard said.
Data came from NASA’s Kepler telescope, which captures information about exoplanets as they move in front of their host stars. To measure the planets’ orbits, Ballard and Sagear focused especially on how long the planets took to move across the face of the stars. Their study also relied on new data from the Gaia telescope, which measured the distance to billions of stars in the galaxy.
“The distance is really the key piece of information we were missing before that allows us to do this analysis now,” Sagear said.
Sagear and Ballard found that stars with multiple planets were the most likely to have the kind of circular orbits that allow them to retain liquid water. Stars with only one planet were the most likely to see tidal extremes that would sterilize the surface.
Since one-third of the planets in this small sample had gentle enough orbits to potentially host liquid water, that likely means that the Milky Way has hundreds of millions of promising targets to probe for signs of life outside our solar system.
JOURNAL
Proceedings of the National Academy of Sciences
METHOD OF RESEARCH
Observational study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
The orbital eccentricity distribution of planets orbiting M dwarfs
ARTICLE PUBLICATION DATE
2-Jun-2023
NJIT researchers awarded $4.6m to unlock mysteries of solar eruptions
National Science Foundation (NSF) awards five-year grant support for Big Bear Solar Observatory research through the maximum of Solar Cycle 25, when the Sun’s explosive activity is expected to peak.
Grant and Award AnnouncementIMAGE: FEBRUARY 26, 2023, A RARE BLIZZARD AT BIG BEAR LAKE, CAL. PRODUCES 7 FEET OF SNOW ALONG THE CAUSEWAY PATH TO THE DOME OF BBSO’S GOODE SOLAR TELESCOPE. view more
CREDIT: CREDIT: SERGEY SHUMKO OF BBSO
A New Jersey Institute of Technology research team led by physics professor Wenda Cao at the university’s Center for Solar Terrestrial Research (CSTR) has been awarded a $4.64 million National Science Foundation grant to continue leading explorations of the Sun’s explosive activity at Big Bear Solar Observatory (BBSO).
The grant marks the largest project that the Solar-Terrestrial Research Program under NSF’s Division of Atmospheric and Geospace Sciences (AGS) supports, extending five more years of baseline funding for all science, instrumentation and education activities at BBSO, located at California’s Big Bear Lake.
The funding supports BBSO research through a key phase of increased activity in the 11-year solar cycle, known as the solar maximum. As more sunspots bubble from the Sun’s surface, sudden releases of energy from the star’s magnetic fields — manifesting as solar flares and coronal mass ejections — are expected to intensify as Solar Cycle 25 reaches its maximum by the summer of 2025.
“Big Bear Solar Observatory and its Goode Solar Telescope are a unique asset to the solar physics community, allowing for uninterrupted solar flare studies important for understanding our Sun and space weather effects,” said Lisa Winter, NSF-AGS program director for Solar-Terrestrial Research and SHINE. “Support for this observatory is especially important as our Sun enters solar maximum.”
BBSO, operated by NJIT-CSTR, has long been at the forefront of solar research as home to the 1.6-meter clear aperture, off-axis Goode Solar Telescope (GST). GST is the world’s second highest-resolution solar telescope and pathfinder to NSF’s 4-meter Inouye Solar Telescope (DKIST) stationed in Maui, Hawaii, which became the world’s largest solar telescope after breaking first light in 2020.
“This grant is essential to maintain the telescope in operation, continue advanced research at BBSO/CSTR, support the current talented engineering team, and educate next generation of scientists and engineers.” said Wenda Cao, BBSO director and member of NSF’s Astronomy and Astrophysics Advisory Committee. “GST was the first facility-class solar telescope built in the U.S. in a generation. Under this grant support, GST will continue to be a major player in high-resolution ground-based observations in the U.S. and worldwide. BBSO will continue playing a crucial and irreplaceable role in science, technology, engineering and education.”
The new grant will enable NJIT-CSTR researchers to continue using GST’s unique imaging capabilities and unapparelled “astronomical seeing” conditions at Big Bear Lake to investigate solar phenomenon as activity on the Sun ramps up. It also promises new GST-DKIST collaborations that could yield unprecedented coverage of solar eruptions as they evolve moment-by-moment.
“The project period covering the maximum of Solar Cycle 25 is an important window to study solar activity, especially solar flares and evolution of solar active regions leading to eruptions,” said Cao, whose team collects a flurry of solar data 24/7 at BBSO that includes measurements of the Sun’s magnetic field, flare energetics in lower solar atmosphere and more, which could potentially offer early warning detection for solar storms back on Earth.
“A notable feature of BBSO is the excellent and stable seeing conditions lasting for hours, which is uniquely required to observe such solar eruptions — key sources of space weather that impact the daily life of humans through effects on communication, transportation, power systems, national defense and space travel.”
Since breaking first light 2009, GST’s observations of the Sun’s surface (photosphere) and lower atmosphere (chromosphere) in visible to near-infrared wavelengths have led to transformative insights into the physics driving solar activity and the nature of the solar atmosphere.
The new grant extends NSF’s previous five-year cycle of funding for BBSO, in which NJIT-CSTR researchers enhanced GST observations with spatial resolution better than 0".1 to answer fundamental questions over the fine-scale energy release in active solar events, including how energy from the Sun is transferred to the star's outermost atmosphere.
BBSO’s GST and other world-class instruments have played a vital role to the international space science community, including providing observational support to NASA missions such as the Parker Solar Probe among others. In 2021, BBSO further bolstered its resources by adding NSF’s Synoptic Optical Long-term Investigations of the Sun (SOLIS) — the most advanced solar telescope for long-term monitoring the “Sun as a whole globe” over the complete solar cycle.
Researchers from 63 universities, observatories and institutes across 21 countries now have access to GST observing time and data, the insights from which have yielded more than 100 peer-reviewed papers since 2018 (including one in Science and six in Nature journals), detailing new discoveries about Earth’s nearest star.
To honor BBSO-driven achievements from the international solar research community, NJIT-CSTR has established the “Goode Solar Telescope Prize.” The inaugural prize was presented to noted solar researcher Young-Deuk Park at the sixth biannual GST Workshop, hosted at the Korea Astronomy and Space Science Institute (KASI) in Daejeon from May 23-26.
The new prize has been created “in recognition of the significant contribution of the BBSO partners and outside communities to the facility.” The GST Prize includes a token cash prize of $1000, which is awarded to “a scientist from around the world for outstanding contributions to BBSO operation, GST science and instrumentation development.”
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