Tuesday, November 05, 2024

SPACE/COSMOS

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In a milestone for Iran’s private space sector, satellites “Kowsar” and “Hodhod” were successfully launched into orbit aboard a Russian Soyuz launcher, marking the country’s initial private effort in satellite production and space deployment. 


Iranian satellites Kowsar and Hodhod were sent into space as part of a payload carried by the Russian Soyuz launcher, which delivered 53 satellites to orbit.

This launch represents a significant advancement for Iran, highlighting the first satellite manufacturing and launching attempt from its private space sector.

The Kowsar satellite, weighing 30 kilograms, is a high-resolution sensing satellite designed for applications in agriculture, natural resource management, environmental monitoring, and disaster response.

With a resolution capability of 3.45 meters, Kowsar surpasses Iran’s goal of producing satellites with 10-meter ground sample distance (GSD) cameras by 2025.

Kowsar has a lifespan of 3.5 years in orbit, positioned at an altitude of 500 kilometers, and is capable of capturing six frames per second over a 15-kilometer range.


Its imaging is achieved using an RGB camera with 3.45-meter resolution and an NIR camera with 5.5-meter resolution, supported by a maximum platform weight of 35 kilograms.

The satellite’s orbital period is 5,677 seconds, with pointing and stability accuracies of 1 degree and 0.05 degrees per second, respectively.

Power is sustained by its 44 watt-hour production capacity, and it consumes 29 watt-hours to operate its payloads.

Meanwhile, Hodhod serves as a small communications satellite intended to create satellite-based communication networks and enhance Internet of Things (IoT) connectivity.

Targeted at regions with limited terrestrial communication access, Hodhod offers communication solutions in remote and inaccessible areas.

Built to the CubeSat standard, the satellite operates in a 500-kilometer orbit and supports precision agriculture, transportation, logistics, and environmental monitoring. Its primary mission focuses on expanding IoT capabilities.



Tasnim News Agency

Tasnim News Agency, which claims to be a private news agency in Iran but is reported be close to the IRGC, was launched in 2012. Its purpose is to cover a variety of political, social, economic and international subjects along with other fields.


The first 3D view of the formation and evolution of globular clusters



Istituto Nazionale di Astrofisica
Image gallery of the 16 globular clusters 

image: 

Image gallery of the 16 globular clusters analysed in order of difference in the kinematic properties observed between the multiple stellar populations. 

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Credit: Credits: ESA/Hubble - ESO - SDSS




A study published today in Astronomy & Astrophysics marks a significant milestone in our understanding of the formation and dynamical evolution of multiple stellar populations in globular clusters (spherical and very compact stellar agglomerates typically populated by 1–2 million stars). This pioneering study, conducted by a group of researchers from the National Institute for Astrophysics (INAF), the University of Bologna, and Indiana University, is the first to perform a 3D kinematic analysis of multiple stellar populations for a representative sample of 16 globular clusters in our Galaxy. It provides a groundbreaking observational description of their kinematic properties (i.e., how stars move within globular clusters) and their long-term evolution from the formation to the present day.

Emanuele Dalessandro, researcher at INAF in Bologna, lead author of the article and coordinator of the working group, explains: "Understanding the physical processes behind the formation and early evolution of globular clusters is one of the most fascinating and debated astrophysical questions of the past 20–25 years. The results of our study provide the first solid evidence that globular clusters formed through multiple star formation events and place fundamental constraints on the dynamical path followed by the clusters throughout their evolution. These results were made possible by a multi-diagnostic approach and the combination of state-of-the-art observations and dynamic simulations." 

The study highlights that the kinematic differences between multiple populations are key to understanding the formation and evolution mechanisms of these ancient structures.

With ages that can reach 12-13 billion years (thus dating back to the dawn of the cosmos), globular clusters are among the first systems to form in the Universe. They represent a typical population of all galaxies. They are compact systems (with masses of several hundred thousand solar masses and sizes of a few parsecs), and they can be observed even in distant galaxies.

"Their astrophysical significance is huge," says Dalessandro, "because they not only help us to test cosmological models of the formation of the Universe due to their age but also provide natural laboratories for studying the formation, evolution, and chemical enrichment of galaxies." Despite globular clusters have been studied for over a century, recent observational results show that our knowledge is still largely incomplete.

"Results obtained in the last two decades have unexpectedly shown that globular clusters consist of more than one stellar population: a primordial one, with chemical properties similar to other stars in the Galaxy, and another with anomalous chemical abundances of light elements such as helium, oxygen, sodium, and nitrogen," says Mario Cadelano, researcher at the Department of Physics and Astronomy at the University of Bologna and INAF associate, one of the authors of the study. "Despite the large number of observations and theoretical models aimed at characterising these populations, the mechanisms regulating their formation are still not understood."

The study is based on the measurement of 3D velocities, i.e., the combination of proper motions and radial velocities, obtained with the ESA Gaia telescope and with data from, among others, the ESO VLT telescope, primarily as part of the MIKiS survey (Multi Instrument Kinematic Survey), a spectroscopic survey specifically aimed at exploring the internal kinematics of globular clusters. The use of these telescopes, from space and the ground, has provided an unprecedented 3D view of the velocity distribution of stars in the selected globular clusters.

The analysis reveals that stars with different abundances of light elements are characterised by different kinematic properties, such as rotational velocities and orbital distributions.

"In this work, we analysed in detail the motion of thousands of stars within each cluster," adds Alessandro Della Croce, a PhD student at INAF in Bologna. "It quickly became clear that stars belonging to different populations have distinct kinematic properties: stars with anomalous chemical composition tend to rotate faster than the others within the cluster and progressively spread from the central regions to the outer ones."

The intensity of these kinematic differences depends on the dynamical age of globular clusters. "These results are consistent with the long-term dynamical evolution of stellar systems, in which stars with anomalous chemical abundances form more centrally concentrated and rotate more rapidly than the standard ones. This, in turn, suggests that globular clusters formed through multiple star formation episodes and provides an important piece of information in defining the physical processes and timescales underlying the formation and evolution of massive stellar clusters," Dalessandro emphasises.

This new 3D view of the motion of stars within globular clusters provides an unprecedented and fascinating framework for the formation and dynamical evolution of these intriguing systems. It also helps to clarify some of the most complex mysteries surrounding the origin of these ancient structures.

Related journal article: “A 3D view of multiple populations kinematics in Galactic globular clusters”, by  E. Dalessandro, M. Cadelano, A. Della Croce, F. I. Aros, E. B. White, E. Vesperini, C. Fanelli, F. R. Ferraro, B. Lanzoni, S. Leanza, L. Origlia. In: Astronomy & Astrophysics.

Contacts:

INAF Press Office - Marco Galliani, +39 335 1778428, ufficiostampa@inaf.it 

World’s first wooden satellite launched into space



By AFP
November 5, 2024

LignoSat, a satellite made from wood and developed by scientists at Kyoto University and Sumitomo Forestry, shown during a press conference in May, 2024 - Copyright JIJI PRESS/AFP/File STR

The world’s first wooden satellite has blasted off on a SpaceX rocket, its Japanese developers said Tuesday, part of a resupply mission to the International Space Station.

Scientists at Kyoto University expect the wooden material to burn up when the device re-enters the atmosphere — potentially providing a way to avoid generating metal particles when a retired satellite returns to Earth.

These particles may negatively impact both the environment and telecommunications, the developers say.

Each side of the box-like experimental satellite, named LignoSat, measures just 10 centimetres (four inches).

It was launched on an unmanned rocket from NASA’s Kennedy Space Center in Florida, Kyoto University’s Human Spaceology Center said.

The satellite, installed in a special container prepared by the Japan Aerospace Exploration Agency, “flew into space safely”, it said in a post on X.

A spokeswoman for LignoSat’s co-developer Sumitomo Forestry told AFP the launch had been “successful”.

It “will arrive at the ISS soon, and will be released to outer space about a month later” to test its strength and durability, she said.

Data will be sent from the satellite to researchers who can check for signs of strain and determine if the satellite can withstand extreme changes in temperature.

“Satellites that are not made of metal should become mainstream,” Takao Doi, an astronaut and special professor at Kyoto University, said at a press conference earlier this year.

Dance of electrons measured in the glow from exploding neutron-stars




University of Copenhagen - Faculty of Science
Neutron star collision 

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Artistic impression of a neutron star collision leaving behind a rapidly expanding cloud of radioactive material

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Credit: NASA GODDARD SPACE FLIGHT CENTER, CI LAB




Black holes: 

The temperature of elementary particles has been observed in the radioactive glow following the collision of two neutron stars and the birth of a black hole. This has, for the first time, made it possible to measure the microscopic, physical properties in these cosmic events. Simultaneously, it reveals how snapshot observations made in an instant represents an object stretched out across time. The discovery was made by astrophysicists from the Niels Bohr Institute, University of Copenhagen and is published in the international scientific journal Astronomy & Astrophysics.

New method of observation shows the creation of heavy elements

The collision of two neutron stars has created the smallest black hole yet observed. The dramatic, cosmic collision resulted in, apart from the birth of a black hole, a ball of fire, expanding with nearly the speed of light. In the following days it shone with a luminosity comparable to hundreds of millions of Suns.

This luminous object, aka a kilonova, shines this bright because of the emission of large amounts of radiation from the decay of the heavy, radioactive elements created in the explosion.

By combining the measurements of the kilonova light, made with telescopes across the Globe, an international team of researchers, led by The Cosmic DAWN Center at the Niels Bohr Institute, have closed in on the enigmatic nature of the explosion and come closer to the answer of an old, astrophysical question: Where do the elements, heavier than iron, come from?

Observatories all over the Globe took part in the observations

“This astrophysical explosion develops dramatically hour by hour, so no single telescope can follow its entire story. The viewing angle of the individual telescopes to the event are blocked by the rotation of the Earth.

But by combining the existing measurements from Australia, South Africa and The Hubble Space Telescope we can follow its development in great detail.

We show that the whole shows more than the sum of the individual sets of data” says Albert Sneppen, PhD student at the Niels Bohr Institute and leader of the new study.

The explosion resembles The Universe shortly after the Big Bang

Just after the collision the fragmented star-matter has a temperature of many billion degrees. A thousand times hotter than even the center of the Sun and comparable to the temperature of the Universe just one second after the Big Bang.

Temperatures this extreme results in electrons not being attached to atomic nuclei, but instead floating around in a so-called ionized plasma.

The electrons “dance” around. But in the ensuing moments, minutes, hours and days, the star-matter cools, just like the entire Universe after the Big Bang.

The fingerprint of Strontium is evidence of the creation of heavy elements

370,000 years after the Big Bang the Universe had cooled sufficiently for the electrons to attach to atomic nuclei and make the first atoms. Light could now travel freely in the Universe because it was no longer blocked by the free electrons.

This means that the earliest light we can see in the history of the Universe is this so-called “cosmic background radiation” – a patchwork of light, constituting the remote background of the night sky. A similar process of the unification of electrons with atomic nuclei can now be observed in the star-matter of the explosion.

One of the concrete results is the observation of heavy elements like Strontium and Yttrium. They are easy to detect, but it is likely that many other heavy elements which we were unsure of the origin of, were also created in the explosion.

“We can now see the moment where atomic nuclei and electrons are uniting in the afterglow. For the first time we see the creation of atoms, we can measure the temperature of the matter and see the micro physics in this remote explosion. It is like admiring three cosmic background radiation surrounding us from all sides, but here, we get to see everything from the outside. We see before, during and after the moment of birth of the atoms”, says Rasmus Damgaard, PhD student at Cosmic DAWN Center and co-author of the study.

Kasper Heintz, co-author and assistant professor at the Niels Bohr Institute continues: “The matter expands so fast and gains in size so raidly, to the extent where it takes hours for the light to travel across the explosion. This is why, just by observing the remote end of the fire ball, we can see further back in the history of the explosion.

Closer to us the electrons have hooked on to atomic nuclei, but on the other side, on the far side of the newborn black hole, the “present” is still just future.



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