CorradoThe '#baritone' of #redgiants refines #cosmicdistance measurements
ScienceActuallyA new type of red giant known as old smokers at the center of our galaxy is rich with heavy elements, so these red giants have a high metallicity. As they age, they can cast off clouds of dust that can obscure the star for a time.
#science #sciencefacts #RedGiants #stars #oldsmokers #oldsmoker #metallicity
NASADiscovery Alert: The Planet that Shouldn’t Be There https://science.nasa.gov/universe/exoplanets/discovery-alert-the-planet-that-shouldnt-be-there/ #NASA #ExoplanetDiscoveries #Exoplanets #GasGiantExoplanets #RedGiants #TESSTransitingExoplanetSurveySatellite
hesgen"Distant planet-devouring star shows Earth's fate"
#astronomy #RedGiants #EndOfTheWorld #PlanetaryDestruction
https://hesgen.substack.com/p/distant-planet-devouring-star-shows
Galaxy MapInteresting new paper on APOGEE red giant ages by the StarHorse team. #StarHorse #APOGEE #RedGiants
Spectroscopic age estimates for APOGEE red-giant stars: Precise spatial and kinematic trends with age in the Galactic disc
Over the last few years, many studies have found an empirical relationship between the abundance of a star and its age. Here we estimate spectroscopic stellar ages for 178 825 red-giant stars observed by the APOGEE survey with a median statistical uncertainty of 17%. To this end, we use the supervised machine learning technique XGBoost, trained on a high-quality dataset of 3060 red-giant and red-clump stars with asteroseismic ages observed by both APOGEE and Kepler. After verifying the obtained age estimates with independent catalogues, we investigate some of the classical chemical, positional, and kinematic relationships of the stars as a function of their age. We find a very clear imprint of the outer-disc flare in the age maps and confirm the recently found split in the local age-metallicity relation. We present new and precise measurements of the Galactic radial metallicity gradient in small age bins between 0.5 and 12 Gyr, confirming a steeper metallicity gradient for $\sim2-5$ Gyr old populations and a subsequent flattening for older populations mostly produced by radial migration. In addition, we analyse the dispersion about the abundance gradient as a function of age. We find a clear power-law trend (with an exponent $β\approx0.15$) for this relation, indicating a relatively smooth radial migration history in the Galactic disc over the past $7-9$ Gyr. Departures from this power law may possibly be related to the Gaia Enceladus merger and passages of the Sagittarius dSph galaxy. Finally, we confirm previous measurements showing a steepening in the age-velocity dispersion relation at around $\sim9$ Gyr, but now extending it over a large extent of the Galactic disc (5 kpc $<R_{\rm Gal}<13$ kpc). [Abridged]
ᴄᴏʀʀᴀᴅᴏ#Astronomers discover irregularities in the #cores of #redgiants
https://phys.org/news/2022-12-astronomers-irregularities-cores-red-giants.html
Astronomers discover irregularities in the cores of red giants
Red giants are dying stars, in advanced stages of stellar evolution, which have depleted the hydrogen in their cores. In a study published today in Nature Communications, a team of astronomers mainly from Instituto de Astrofísica e Ciências do Espaço (IA), have found new evidence that red giant stars experience "glitches"—sharp structural variations—in their inner core.
Phys.orgReferenced link: https://phys.org/news/2022-12-astronomers-irregularities-cores-red-giants.html
Discuss on https://discu.eu/q/https://phys.org/news/2022-12-astronomers-irregularities-cores-red-giants.html
Originally posted by Phys.org / @[email protected]: https://twitter.com/physorg_com/status/1603782014657757185#m
Astronomers discover irregularities in the cores of #redgiants @iastropt @NatureComms https://www.nature.com/articles/s41467-022-34986-z https://phys.org/news/2022-12-astronomers-irregularities-cores-red-giants.html
Astronomers discover irregularities in the cores of red giants
Red giants are dying stars, in advanced stages of stellar evolution, which have depleted the hydrogen in their cores. In a study published today in Nature Communications, a team of astronomers mainly from Instituto de Astrofísica e Ciências do Espaço (IA), have found new evidence that red giant stars experience "glitches"—sharp structural variations—in their inner core.
Massimo Luciani#astronomy #exoplanets #stars #RedGiants An article published in the journal "Astronomy and Astrophysics" reports the discovery of 26 planetary systems within the TAPAS (Tracking Advanced Planetary Systems) project.
https://english.tachyonbeam.com/2021/03/10/planets-discovered-orbiting-ancient-stars/
https://english.tachyonbeam.com/2021/03/10/planets-discovered-orbiting-ancient-stars/