Results 11 to 20 of about 2,085 (265)

Stellar Ages: A Code to Infer Properties of Stellar Populations

open access: yesThe Astrophysical Journal
Abstract We present a novel statistical algorithm, Stellar Ages, which currently infers the age, metallicity, and extinction posterior distributions of stellar populations from their magnitudes. While this paper focuses on these parameters, the framework is readily adaptable to include additional properties, such as rotation, in future ...
Joseph J. Guzman   +4 more
openaire   +3 more sources

Magnetic Activity Evolution of Solar-like Stars. I. S ph–Age Relation Derived from Kepler Observations

open access: yesThe Astrophysical Journal, 2023
The ages of solar-like stars have been at the center of many studies such as exoplanet characterization or Galactic-archeology. While ages are usually computed from stellar evolution models, relations linking ages to other stellar properties, such as ...
Savita Mathur   +11 more
doaj   +1 more source

Disentangling Stellar Age Estimates from Galactic Chemodynamical Evolution

open access: yesThe Astrophysical Journal, 2023
Stellar ages are key for determining the formation history of the Milky Way, but are difficult to measure precisely. Furthermore, methods that use chemical abundances to infer ages may entangle the intrinsic evolution of stars with the chemodynamical ...
Jeff Shen   +4 more
doaj   +1 more source

Cosmological Constant from Boundary Condition and Its Implications beyond the Standard Model

open access: yesUniverse, 2023
Standard cosmology has long been plagued by a number of persistent problems. The origin of the apparent acceleration of the cosmic expansion remains enigmatic.
Jan O. Stenflo
doaj   +1 more source

Living with a Red Dwarf: X-Ray, UV, and Ca ii Activity–Age Relationships of M Dwarfs

open access: yesThe Astrophysical Journal, 2023
The vast majority of stars in the nearby stellar neighborhood are M dwarfs. Their low masses and luminosities result in slow rates of nuclear evolution and minimal changes to the stars’ observable properties, even along astronomical timescales.
Scott G. Engle
doaj   +1 more source

The Abundance of S-Process Elements: Temporal and Spatial Trends from Open Cluster Observations

open access: yesUniverse, 2022
Spectroscopic observations of stars belonging to open clusters, with well-determined ages and distances, are a unique tool for constraining stellar evolution, nucleosynthesis, mixing processes, and, ultimately, Galactic chemical evolution.
Laura Magrini   +8 more
doaj   +1 more source

Wrinkles in Time. I. Rapid Rotators Found in High-eccentricity Orbits

open access: yesThe Astrophysical Journal, 2023
Recent space-based missions have ushered in a new era of observational astronomy, where high-cadence photometric light curves for thousands to millions of stars in the solar neighborhood can be used to test and apply stellar age-dating methods, including
Rayna Rampalli   +4 more
doaj   +1 more source

TESS Hunt for Young and Maturing Exoplanets (THYME). IX. A 27 Myr Extended Population of Lower Centaurus Crux with a Transiting Two-planet System

open access: yesThe Astronomical Journal, 2023
We report the discovery and characterization of a nearby (∼85 pc), older (27 ± 3 Myr), distributed stellar population near Lower Centaurus Crux (LCC), initially identified by searching for stars comoving with a candidate transiting planet from TESS (HD ...
Mackenna L. Wood   +37 more
doaj   +1 more source

Theoretical Re-evaluations of Scaling Relations between SMBHs and Their Host Galaxies–2. Importance of AGN Feedback Suggested by Stellar Age–Velocity Dispersion Relation

open access: yesFrontiers in Astronomy and Space Sciences, 2017
We present the galactic stellar age—velocity dispersion relation obtained from a semi-analytic model of galaxy formation. We divide galaxies into two populations: galaxies which have over-massive/under-massive black holes (BHs) against the best-fitting ...
Hikari Shirakata   +3 more
doaj   +1 more source

THE AGE AND STELLAR PARAMETERS OF THE PROCYON BINARY SYSTEM [PDF]

open access: yesThe Astrophysical Journal, 2013
Accepted for the Astrophysical Journal, in ...
Liebert, James   +4 more
openaire   +2 more sources

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