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The analysis of stellar spectra depends upon the effective temperature (Teff) and the surface gravity (log g). However, the estimation of log g with high accuracy is challenging. A classical approach is to search for log g that satisfies…

Solar and Stellar Astrophysics · Physics 2021-07-07 Noriyuki Matsunaga , Mingjie Jian , Daisuke Taniguchi , Scarlet Saez Elgueta

During the survey phase of the Kepler mission, several thousands of stars were observed in short cadence, allowing the detection of solar-like oscillations in more than 500 main-sequence and sub-giant stars. Later, the Kepler Science Office…

Solar and Stellar Astrophysics · Physics 2021-12-29 S. Mathur , R. A. García , S. N. Breton , A. R. G. Santos , B. Mosser , D. Huber , M. Sayeed , L. Bugnet , A. Chontos

Several works have recently applied Jeans modelling to Gaia-based datasets to infer the circular velocity curve for the Milky Way. Such works have consistently found evidence for a continuous decline in the rotation curve beyond $\sim$15kpc…

Astrophysics of Galaxies · Physics 2024-12-04 Orlin Koop , Teresa Antoja , Amina Helmi , Thomas M. Callingham , Chervin F. P. Laporte

In this paper we describe Kea a new spectroscopic fitting method to derive stellar parameters from moderate to low signal/noise, high-resolution spectra. We developed this new tool to analyze the massive data set of the Kepler mission…

Solar and Stellar Astrophysics · Physics 2016-06-29 Michael Endl , William D. Cochran

Owing to the remarkable photometric precision of space observatories like Kepler, stellar and planetary systems beyond our own are now being characterized en masse for the first time. These characterizations are pivotal for endeavors such…

Solar and Stellar Astrophysics · Physics 2017-04-03 Earl P. Bellinger , George C. Angelou , Saskia Hekker , Sarbani Basu , Warrick Ball , Elisabeth Guggenberger

Time-domain surveys have advanced astronomical research by revealing diverse variable phenomena, from stellar flares to transient events. The scale and complexity of survey data, along with the demand for rapid classification, present…

Instrumentation and Methods for Astrophysics · Physics 2025-12-10 Xiaoxiong Zuo , Yihan Tao , Yang Huang , Zhixuan Kang , Huaxi Chen , Chenzhou Cui , Jiashu Pan , Xiao Kong , Xiaoyu Tang , Henggeng Han , Haiyang Mu , Yunfei Xu , Dongwei Fan , Guirong Xue , Ali Luo , Jifeng Liu

Large scale, deep survey missions such as GAIA will collect enormous amounts of data on a significant fraction of the stellar content of our Galaxy. These missions will require a careful optimisation of their observational systems in order…

Astrophysics · Physics 2010-10-28 Coryn A. L. Bailer-Jones

Context. Precise stellar parameters are crucial in exoplanet research for correctly determining of the planetary parameters. For stars hosting a transiting planet, determining of the planetary mass and radius depends on the stellar mass and…

Earth and Planetary Astrophysics · Physics 2015-06-17 A. Mortier , N. C. Santos , S. G. Sousa , J. M. Fernandes , V. Zh. Adibekyan , E. Delgado Mena , M. Montalto , G. Israelian

We derive and publish data-driven estimates of stellar metallicities [M/H] for 175 million stars with low-resolution XP spectra published in Gaia DR3. The [M/H] values, along with Teff and logg, are derived using the XGBoost algorithm,…

Solar and Stellar Astrophysics · Physics 2023-07-12 Rene Andrae , Hans-Walter Rix , Vedant Chandra

We present a method for deriving stellar fundamental parameters. It is based on a regularized sliced inverse regression (RSIR). We first tested it on noisy synthetic spectra of A, F, G, and K-type stars, and inverted simultaneously their…

Solar and Stellar Astrophysics · Physics 2019-01-31 S. Kassounian , M. Gebran , F. Paletou , V. Watson

Hot subdwarf stars are mostly stripped red giants that can exhibit photometric variations due to stellar pulsations, eclipses, the reflection effect, ellipsoidal modulation, and Doppler beaming. Detailed studies of their light curves help…

We introduce a method for producing a galaxy sample unbiased by surface brightness and stellar mass, by selecting star-forming galaxies via the positions of core-collapse supernovae (CCSNe). Whilst matching $\sim$2400 supernovae from the…

Astrophysics of Galaxies · Physics 2019-01-23 Thomas M. Sedgwick , Ivan K. Baldry , Philip A. James , Lee S. Kelvin

We present new calibrations of stellar parameters of O stars at solar metallicity taking non-LTE, wind, and line-blanketing effects into account. Gravities and absolute visual magnitudes are derived from results of recent spectroscopic…

Astrophysics · Physics 2009-05-29 F. Martins , D. Schaerer , D. J. Hillier

Using population synthesis tools we create a synthetic Kepler Input Catalogue (KIC) and subject it to the Kepler Stellar Classification Program (SCP) method for determining stellar parameters such as the effective temperature Teff and…

Solar and Stellar Astrophysics · Physics 2013-06-06 R. Farmer , U. Kolb , A. J. Norton

Temperature, surface gravity, and metallicitity are basic stellar atmospheric parameters necessary to characterize a star. We aim to improve the description of the spectroscopic temperatures especially for the cooler stars where the…

Solar and Stellar Astrophysics · Physics 2015-06-15 M. Tsantaki , S. G. Sousa , V. Zh. Adibekyan , N. C. Santos , A. Mortier , G. Israelian

Surface gravity is one of a star's basic properties, but it is difficult to measure accurately, with typical uncertainties of 25-50 per cent if measured spectroscopically and 90-150 per cent photometrically. Asteroseismology measures…

Solar and Stellar Astrophysics · Physics 2015-06-17 Fabienne A. Bastien , Keivan G. Stassun , Gibor Basri , Joshua Pepper

The second Gaia data release (Gaia-DR2) contains, beyond the astrometry, three-band photometry for 1.38 billion sources. We have used these three broad bands to infer stellar effective temperatures, Teff, for all sources brighter than G=17…

A large fraction of cool, low-mass stars exhibit brightness fluctuations that arise from a combination of convective granulation, acoustic oscillations, magnetic activity, and stellar rotation. Much of the short-timescale variability takes…

Solar and Stellar Astrophysics · Physics 2015-06-18 Steven R. Cranmer , Fabienne A. Bastien , Keivan G. Stassun , Steven H. Saar

Large-scale and deep sky survey missions are rapidly collecting a large amount of stellar spectra, which necessitate the estimation of atmospheric parameters directly from spectra and makes it feasible to statistically investigate latent…

Solar and Stellar Astrophysics · Physics 2015-04-13 Xiangru Li , Q. M. Jonathan Wu , Ali Luo , Yongheng Zhao , Yu Lu , Fang Zuo , Tan Yang , Yongjun Wang

Detailed chemical studies of F/G/K -- or Solar-type -- stars have long been routine in stellar astrophysics, enabling studies in both Galactic chemodynamics, and exoplanet demographics. However, similar understanding of the chemistry of M…