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Related papers: Older Ages for 23 Pre-Main Sequence Stars in Upper…

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We used the Immersion GRating Infrared Spectrometer (IGRINS) to determine fundamental parameters for 61 K- and M-type young stellar objects (YSOs) located in the Ophiuchus and Upper Scorpius star-forming regions. We employed synthetic…

We present a catalog of ~100,000 periodic variable stars in TESS FFI data among members of widely distributed moving groups identified with Gaia in the previous papers in the series. By combining the periods from our catalog attributable to…

Solar and Stellar Astrophysics · Physics 2022-09-21 Marina Kounkel , Keivan G. Stassun , Luke G. Bouma , Kevin Covey , Lynne A. Hillenbrand , Jason Lee Curtis

Pre-main sequence (PMS) models provide invaluable tools for the study of star forming regions as they allow to assign masses and ages to young stars. Thus it is of primary importance to test the models against observations of PMS stars with…

Solar and Stellar Astrophysics · Physics 2015-05-30 Mario Gennaro , Pier Giorgio Prada Moroni , Emanuele Tognelli

We show that the extended main sequence turnoffs seen in intermediate age Large Magellanic Cloud (LMC) clusters, often attributed to age spreads of several hundred Myr, may be easily accounted for by variable stellar rotation in a coeval…

Solar and Stellar Astrophysics · Physics 2015-07-02 Timothy D. Brandt , Chelsea X. Huang

Using semi-empirical isochrones, we find the age of the Taurus star-forming region to be 3-4 Myr. Comparing the disc fraction in Taurus to young massive clusters suggests discs survive longer in this low density environment. We also present…

Solar and Stellar Astrophysics · Physics 2016-02-03 Jon M. Rees , T. Wilson , C. P. M. Bell , R. D. Jeffries , Tim Naylor

We determine which are the mechanisms accelerating the surface of single stars during the Main Sequence evolution. We have computed 112 stellar models of four different initial masses between 3 and 60 M_sun, at four different metallicities…

Astrophysics · Physics 2014-11-18 S. Ekström , G. Meynet , A. Maeder , F. Barblan

We study the structure, age and metallicity gradients, and dynamical evolution using a cosmological zoom-in simulation of a Milky Way-mass galaxy from the Feedback in Realistic Environments project. In the simulation, stars older than 6 Gyr…

We present an analysis of K2 light curves (LCs) for candidate members of the young Upper Sco (USco) association $\sim$8 Myr) and the neighboring Rho Oph embedded cluster ($\sim$1 Myr). We establish $\sim$1300 stars as probable members,…

Solar and Stellar Astrophysics · Physics 2018-05-02 L. M. Rebull , J. R. Stuaffer , A. M. Cody , L. A. Hillenbrand , T. J. David , M. Pinsonneault

There is growing evidence that star clusters can no longer be considered simple stellar populations (SSPs). Intermediate and old age clusters are often found to have extended main sequence turn-offs (eMSTOs) which are difficult to explain…

Solar and Stellar Astrophysics · Physics 2019-04-10 Emma R. Beasor , Ben Davies , Nathan Smith , Nate Bastian

We investigate the stellar populations of galaxies in clusters at different dynamical stages, aiming to identify possible effects of the relaxation state of the cluster or subcluster on the star formation histories of its galaxies. We have…

Astrophysics of Galaxies · Physics 2018-12-19 N. R. Soares , S. B. Rembold

The Ursa Major Moving Group (UMa) is one of the closest stellar associations, yet its age has remained controversial, with published estimates ranging from 200 Myr to 1 Gyr. We present a comprehensive age analysis using the largest sample…

Solar and Stellar Astrophysics · Physics 2026-01-15 Julia Sheffler , Max Clark , Melinda Soares-Furtado , Adam Distler , Ritvik Sai Narayan , Jenna Karcheski , Kenneth Nordsieck

We present deep Hubble Space Telescope Advanced Camera for Surveys observations of the stellar populations in two fields lying at 20 and 23 kpc from the centre of M31 along the south-west semi-major axis. These data enable the construction…

We present results of age determination based on the standard procedure of isochrone fitting for about 600 star clusters younger than about 1.2 Gyr from the central parts of the LMC. Comparison of age distributions of star clusters from the…

Astrophysics · Physics 2007-05-23 G. Pietrzynski , A. Udalski

The formation timescale of the Milky Way thick disk is one of the central debates in Galactic archaeology. The age-metallicity relation (AMR), formation timescale, and chemical evolution gradients are frequently used to infer a rapid…

Astrophysics of Galaxies · Physics 2026-05-25 Zhipeng Zhang

We revisit the determination of the age of the Universe from galactic globular clusters, extending previous analyses by explicitly accounting for the presence of multiple stellar populations within each cluster. Using high--quality…

Astrophysics of Galaxies · Physics 2026-03-06 David Valcin , Raul Jimenez , Carmela Lardo , Uroš Seljak , Licia Verde

We report the results of a study of archival SuperWASP light curves for stars in Scorpius-Centaurus (Sco-Cen), the nearest OB association. We use SuperWASP time-series photometry to extract rotation periods for 189 candidate members of the…

Solar and Stellar Astrophysics · Physics 2017-08-02 Samuel N. Mellon , Eric E. Mamajek , Thomas E. Oberst , Mark J. Pecaut

We analyze the present-day structure and assembly history of a high resolution hydrodynamic simulation of the formation of a Milky Way (MW)-like disk galaxy, from the "Eris" simulation suite, dissecting it into cohorts of stars formed at…

Based on high resolution optical spectra obtained with ESPaDOnS at CFHT, we determine fundamental parameters (\Teff, R, \Lbol, \logg\ and metallicity) for 59 candidate members of nearby young kinematic groups. The candidates were identified…

Solar and Stellar Astrophysics · Physics 2015-06-22 Lison Malo , René Doyon , Gregory A. Feiden , Loïc Albert , David Lafrenière , Étienne Artigau , Jonathan Gagné , Adric Riedel

Estimating stellar ages is important for advancing our understanding of stellar and exoplanet evolution and investigating the history of the Milky Way. However, ages for low-mass stars are hard to infer as they evolve slowly on the main…

Solar and Stellar Astrophysics · Physics 2022-03-23 Yuxi , Lu , Ruth Angus , Jason L. Curtis , Trevor J. David , Rocio Kiman

The discovery of close in, giant planets (hot Jupiters) with orbital angular momentum vectors misaligned with respect to the rotation axis of their host stars presents problems for planet formation theories in which planets form in discs…

Solar and Stellar Astrophysics · Physics 2019-01-16 Claire L Davies