The Space Force is experimenting with commercial capabilities to inform its long-term strategy for space-based environmental monitoring.
Category: space – Page 29
Webb sheds more light on composition of planetary debris around nearby white dwarf
Using the James Webb Space Telescope (JWST), astronomers have performed infrared observations of a planetary debris disk around a nearby white dwarf known as GD 362. Results of the new observations, presented October 8 on the arXiv preprint server, yield important insights into the chemical composition of this disk.
White dwarfs (WDs) are stellar cores left behind after a star has exhausted its nuclear fuel. Due to their high gravity, they are known to have atmospheres of either pure hydrogen or pure helium.
However, there exists a small fraction of WDs that shows traces of heavier elements, and they are believed to be accreting planetary material. Studies of this material around WDs, which often forms dust disks, is essential to improving our knowledge of how planets form and evolve.
Gaia provides a deep look into the galactic open cluster NGC 2506
Using ESA’s Gaia satellite and NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers from the Ege University in Turkey and elsewhere have observed a galactic open cluster known as NGC 2506. Results of the observational campaign, published October 7 on the arXiv pre-print server, put more constraints on the properties of this cluster.
In general, groups of stars formed from the same giant molecular cloud and loosely gravitationally bound to each other are known as open clusters (OCs). Inspecting galactic OCs in detail could be crucial for improving our understanding of the formation and evolution of our Milky Way galaxy.
NGC 2,506 is a mildly-elongated OC estimated to be located some 12,700 light years away, near the galactic anti-center. It is a well-populated, metal-poor, intermediate-age cluster with a radius of about 18.5 light years.
Not So Dead After All: Astronomers Reveal the Secret Behind Inflated White Dwarfs
White dwarfs are the dense, compact remains left behind when stars exhaust their nuclear fuel, a process that will one day occur to our own Sun. These stellar remnants are known as degenerate stars because their internal physics defy normal expectations: as they gain mass, they actually become smaller in size.
Many white dwarfs exist in pairs, forming what are known as binary systems, where two stars orbit each other. Most of these systems are ancient by galactic standards and have cooled over time to surface temperatures near 4,000 Kelvin.
Yet, astronomers have recently identified a remarkable group of short-period binary systems in which the stars complete an orbit in less than an hour. Surprisingly, these white dwarfs appear to be about twice as large as models predict, with much higher surface temperatures ranging from 10,000 to 30,000 Kelvin.
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Mysterious gullies on Mars appear to have been carved by burrowing CO₂ ice blocks
Did life really exist on Mars after all? Unfortunately, there is no conclusive evidence for this yet. Nevertheless, it would seem that some form of life was the driving force behind the mysterious Martian dune gullies. Earth scientist Dr. Lonneke Roelofs from Utrecht University has investigated how these gullies were formed. In a test setup, she observed that blocks of CO2 ice “dug” these gullies in a unique way.
“It felt like I was watching the sandworms in the film Dune,” Roelofs says. Her findings are published in Geophysical Research Letters.
Other researchers had previously suspected that these blocks could play a role in the formation of the gullies. Roelofs has now proven this by having CO2 ice blocks actually dig those gullies in an experiment—a phenomenon that we do not know here on Earth and that had never been observed by anyone before.
Astronomers uncover collisional signature of filamentary structures in galactic G34 molecular cloud
Using CO (J=1–0) molecular line data obtained from the 13.7-meter millimeter-wave telescope at the Purple Mountain Observatory’s Delingha Observatory, Sun Mingke, a Ph.D. student from the Xinjiang Astronomical Observatory of the Chinese Academy of Sciences and his collaborators conducted a systematic study of the galactic molecular cloud G34. They revealed the collisional signatures and dynamical mechanisms of filamentary structures in this region. The results are published in Astronomy & Astrophysics.
Star formation is one of the key processes that drive the evolution of galaxies and the interstellar medium. Recent observations and theoretical studies suggest that interactions and collisions between large-scale filamentary structures may play an important role in triggering high-mass star formation.
In this study, the researchers identified two giant filaments, designated F1 and F2, in the G34 region. By analyzing their spatial distribution and velocity field, the researchers found clear evidence of ongoing collisions between the filaments.