Results 81 to 90 of about 837,700 (191)
The axisymmetric stellar wind of AG Carinae
The Astrophysical Journal, 1994 We present optical linear spectropolarimetry of the Luminous Blue Variable AG Carinae obtained after a recent visual brightness increase. The absence of He II lambda 4686 emission, together with the weakening of the He I spectrum and the appearance of Fe lines in the region around 5300 A, confirm that AG Car has started a new excursion across the HR ...
Regina E. Schulte-Ladbeck +4 more
openaire +1 more source
Stellar Cruise Control: Weakened Magnetic Braking Leads to Sustained Rapid Rotation of Old Stars
The Astrophysical JournalDespite a growing sample of precisely measured stellar rotation periods and ages, the strength of magnetic braking and the degree of departure from standard (Skumanich-like) spin-down have remained persistent questions, particularly for stars more ...
Nicholas Saunders +10 more
doaj +1 more source
Spatially resolved stellar-to-total dynamical mass relation
Astronomy & AstrophysicsContext. In our standard cosmological model, galaxy assembly is inherently linked to the hierarchical growth of dark matter halos, which provide the gravitational framework in which highly complex baryonic processes unfold.
Scholz-Díaz L. +3 more
doaj +1 more source
Dependence of the LMXB population on stellar age
, 2012 We investigate the dependence of the low-mass X-ray binary (LMXB) population in early-type galaxies on stellar age, by selecting 20 massive nearby early-type galaxies from the Chandra archive occupying a relatively narrow range of masses and spanning a broad range of ages, from 1.6 Gyr to more than 10 Gyrs, with the median value of 6 Gyrs.
Gilfanov, Marat +2 more
openaire +2 more sources
Evolution of Stellar Activity and Habitable Zone. II. Ca II H and K Emissions of Late-type Dwarfs
The Astrophysical Journal Supplement SeriesStellar chromospheric activity serves as a valuable proxy for estimating stellar ages, though its applicable range and accurate functional form are still debated.
Henggeng Han +5 more
doaj +1 more source
The star formation history of early-type galaxies in the fornax cluster [PDF]
, 1998 We have measured central line strengths and line-strength gradients for a complete sample of early-type galaxies in the Fornax cluster, comprising 11 elliptical and 11 lenticular galaxies, more luminous than M(_B) = -17.
Kuntschner, Harald, Kuntschner, H.
core
Calibrating [C/N] Abundance Ratios Using Star Clusters To Determine Stellar Ages
, 2021 Through the use of large-scale surveys, astronomers are able to investigate Galactic evolution, both kinematically and chemically, however determining reliable stellar ages has been elusive.
Spoo, Taylor
core
The Influence of Atomic Diffusion on Stellar Ages and Chemical Tagging
, 2020 In the era of large stellar spectroscopic surveys, there is an emphasis on deriving not only stellar abundances but also the ages for millions of stars.
Dotter, Aaron +3 more
core +1 more source
The HAges Catalog: Stellar Ages for High-priority HWO Target Stars
The Astrophysical JournalPrecise stellar ages (uncertainties ≲1 Gyr, or ∼20% at solar age) are required to discern evolutionary trends in atmospheric biosignatures of terrestrial habitable zone exoplanets surveyed by the Habitable Worlds Observatory (HWO) and will aid in ...
Austin Ware +2 more
doaj +1 more source
The Absolute Age of Milky Way Globular Clusters
The Astrophysical JournalGlobular clusters (GCs) provide statistically significant coeval populations of stars spanning various evolutionary stages, allowing robust constraints on stellar evolution model parameters and ages.
Jiaqi (Martin) Ying +4 more
doaj +1 more source