Results 1 to 10 of about 20,344 (216)
Kinematics of Tycho-2 red giant clump stars [PDF]
Astronomy Letters, 2009 Based on the Ogorodnikov-Milne model, we analyze the proper motions of 95 633 red giant clump (RGC) stars from the Tycho-2 Catalogue. The following Oort constants have been found: A = 15.9+-0.2 km/s/kpc and B = -12.0+-0.2 km/s/kpc.
V. V. Bobylev +3 more
core +6 more sources
Evidence of structural discontinuities in the inner core of red-giant stars [PDF]
Nature Communications, 2022 Red giant stars enter the clump phase as the helium in the cores start fusing. Here, the authors show evidence for large core structural discontinuities in 7% of Kepler satellite clump star data implying that the mixing region beyond the convective core ...
Mathieu Vrard +5 more
doaj +2 more sources
Lithium evolution in the low-mass evolved stars with asteroseismology and LAMOST spectroscopy [PDF]
Fundamental ResearchLithium is an ancient element that was first produced by the Big Bang Nucleosynthesis (BBN) a few minutes after the birth of the Universe. Lithium is a sensitive tracer for a number of processes in a variety of astrophysical environments due to its multi-
Hong-Liang Yan +9 more
doaj +2 more sources
Study of a Red Clump Giant, KIC 11087027, with High Rotation and Strong Infrared Excess—Evidence of Tidal Interaction for High Lithium Abundance [PDF]
The Astrophysical Journal LettersThis Letter presents results from Kepler photometric light curves and a high-resolution spectroscopic study of a super-Li-rich giant KIC11087027. Using the light-curve analysis, we measured the star’s rotational period P _rot = 30.4 ± 0.1 days, which ...
Raghubar Singh +4 more
doaj +2 more sources
The Astrophysical Journal Letters, 2023 In this work, we studied the distribution of lithium abundances in giants as a function of stellar mass. We used a sample of 1240 giants common among Kepler photometric and LAMOST medium-resolution ( R ≈ 7500) spectroscopic survey fields.
Anohita Mallick +2 more
doaj +1 more source
Inferring Coupling Strengths of Mixed-mode Oscillations in Red Giant Stars Using Deep Learning
The Astrophysical Journal, 2023 Asteroseismology is a powerful tool that may be applied to shed light on stellar interiors and stellar evolution. Mixed modes, behaving like acoustic waves in the envelope and buoyancy modes in the core, are remarkable because they allow for probing the ...
Siddharth Dhanpal +5 more
doaj +1 more source
Investigating APOKASC Red Giant Stars with Abnormal Carbon-to-nitrogen Ratios
The Astrophysical Journal, 2023 The success of galactic archeology and the reconstruction of the formation history of our Galaxy relies critically on precise ages for large populations of stars. For evolved stars in the red clump and red giant branch, the carbon-to-nitrogen ratio ([C/N]
Erica Bufanda +4 more
doaj +1 more source
The Astronomical Journal, 2023 We present a BVI photometric study of four old open clusters (OCs) in the the Milky Way, Czernik 30, Berkeley 34, Berkeley 75, and Berkeley 76 using the observation data obtained with the Small and Moderate Aperture Research Telescope System 1.0 m ...
Hyobin Im +4 more
doaj +1 more source
Asteroseismology of KIC 8263801:Is it a member of NGC 6866 and a red clump star? [PDF]
, 2018 We present an asteroseismic analysis of the Kepler light curve of KIC 8263801, a red-giant star in the open cluster NGC 6866 that has previously been reported to be a helium-burning red-clump star.
Basu, Sarbani +4 more
core +2 more sources
A New Method for the Asteroseismic Determination of the Evolutionary State of Red-Giant Stars [PDF]
, 2016 Determining the ages of red-giant stars is a key problem in stellar astrophysics. One of the difficulties in this determination is to know the evolutionary state of the individual stars -- i.e. have they started to burn Helium in their cores? That is the
Basu, Sarbani +3 more
core +2 more sources