All articles tagged with #gaia
Astronomers have found 20 metal-poor stars near the Milky Way's disk that likely originated in a now-destroyed dwarf galaxy called Loki; the stars' shared chemistry and orbits suggest Loki was absorbed about 10 billion years ago, offering new clues about the Milky Way's early growth through data from Gaia and follow-up observations.
Astronomers identified 20 old, very metal-poor stars orbiting close to the Milky Way’s disk whose chemistry and motions suggest they originated in a dwarf galaxy nicknamed Loki that merged with the Milky Way more than 10 billion years ago. The inferred Loki had about 1.4 billion solar masses, and the study shows how ancient mergers can leave detectable stellar signatures in the inner Galaxy; further observations are needed to confirm Loki and map similar remnants.
Astronomers mapped a clear boundary to the Milky Way’s star-forming disk at about 40,000 light-years from the center by analyzing stellar ages and using galaxy simulations; inside this radius star formation continues, while beyond it older stars migrated outward, creating a distinctive U-shaped age pattern.
Astronomers mapped the Milky Way’s star-forming disk and find that active star formation ends at roughly 40,000 light-years from the center; the Sun sits well inside this boundary at about 26,000 ly. The stellar age distribution forms a U shape—young toward the center and older beyond the edge due to radial migration where stars born closer in travel outward along spiral arms. Simulations suggest a sharp drop in star-formation efficiency at 40,000 ly, potentially linked to the Galaxy’s bar or disk warp. The finding relies on Gaia data plus ground-based spectroscopy from LAMOST and APOGEE and is published in Astronomy & Astrophysics.
Astronomers mapped ages for about 100,000 bright stars across the Milky Way’s disk and found that active star formation effectively ends at roughly 40,000 light-years from the Galactic center, creating a U-shaped age profile where younger stars lie inward and older ones outward. The outer stars likely reach those distances via radial migration along spiral waves rather than in situ formation. The boundary’s origin could relate to the Milky Way’s bar or disk warp, with Gaia data combined with ground-based spectroscopy (LAMOST and APOGEE) and simulations helping explain the phenomenon, though the exact mechanism remains under study.
Using Gaia data, researchers argue the Pleiades would have looked like seven distinct stars 100,000 years ago, offering a plausible origin for cross-cultural 'Seven Sisters' myths and suggesting oral traditions could preserve a single star-based story for up to about 4,000 generations, though the claim is inferential and not proven.
A University of Chicago undergraduate team using Sloan Digital Sky Survey data identified SDSSJ0715-7334 as an ultra-pristine, extremely metal-poor star (0.005% of the Sun’s metals) that likely formed in the Large Magellanic Cloud before migrating into the Milky Way; Gaia data confirms its past orbit and its carbon is undetectable, offering a rare glimpse into the conditions of the early universe.
Researchers using Gaia data and the NASA Exoplanet Archive identify 45 rocky exoplanets in the habitable zone (plus 24 near-edge worlds) that could sustain Earth-like conditions, spotlighting planets such as Proxima Centauri b and TRAPPIST-1 d–g. The list should guide observations with JWST, the Roman Space Telescope, ELT, LIFE and other missions to study atmospheres, test habitability limits, and refine the definition of the habitable zone.
Astronomers using Gaia data found Sun-like stars, including the Sun, clustered around 4–6 billion years old at similar distances from the Galactic center, implying the Sun migrated outward from the core; this migration helps time the Milky Way's corotation barrier and suggests moving away from the center aided life’s emergence on Earth.
A Gaia-based study of ~2 billion stars found 6,594 solar twins clustered in the 4–6 billion-year range near the Sun’s current orbit, suggesting a mass outward migration from the galactic core during the Milky Way’s bar formation. The temporary lowering of a corotation barrier likely allowed Sun-like stars to drift outward, placing our Sun in a calmer region conducive to life.
Researchers using Gaia data analyzed nearly two million stars and found 6,594 Sun-like stars around 4–6 billion years old, suggesting the Sun migrated from the Milky Way's inner regions to its current calmer orbit about 26,000–28,000 light-years from the center; the move likely occurred as the galaxy's central bar formed and accelerated stellar birth, moving many stars outward, which would have given Earth a more benign environment for life to emerge and evolve; studying solar twins helps reconstruct the solar system's early history.
Using Gaia data, scientists found that the Sun and thousands of Sun-like stars formed near the Milky Way's center about 4–6 billion years ago and migrated outward in a synchronized wave, likely aided by the galaxy's central bar, reshaping our understanding of the Sun’s origin and the Milky Way's history.
Astronomers using the James Webb Space Telescope refined the orbit of asteroid 2024 YR4, ruling out a collision with the Moon and showing it will pass about 13,200 miles (21,200 km) above the lunar surface in 2032. This closes the earlier 4.3% Moon-impact risk that existed due to orbital uncertainty, with Gaia-star measurements helping to nail down the asteroid’s path.
Gaia data reveal Palomar 5, a Milky Way globular cluster with an extensive tidal stream, may host over 100 stellar-mass black holes, making up about 20% of the cluster’s mass. Detailed simulations that include these black holes show they can eject stars into the cluster’s tidal tails, hastening its dissolution into a stream of black holes that will orbit the galactic center in around a billion years. The finding suggests such black-hole-rich clusters may be common and could be important for understanding black-hole mergers.
Gaia data and N-body simulations indicate Palomar 5 hosts a substantial population of stellar-mass black holes—over 20% of its mass—which drove stars into its broad tidal stream; the cluster is on track to dissolve in about a billion years, leaving a black-hole–dominated remnant, suggesting globular clusters commonly harbor black holes and are key sites for future black hole mergers, with Palomar 5 acting as a Rosetta Stone for stream formation.