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This work addresses a procedure to estimate fundamental stellar parameters such as T eff , logg, [Fe/H], and v sin i using a dimensionality reduction technique called Principal Component Analysis (PCA), applied to a large database of…

Solar and Stellar Astrophysics · Physics 2015-08-18 W. Farah , M. Gebran , F. Paletou , R. Blomme

A new full-sky catalog of Radial Velocity standard stars is being built for the determination of the Radial Velocity Zero Point of the RVS on board of Gaia. After a careful selection of 1420 candidates matching well defined criteria, we are…

Astrophysics of Galaxies · Physics 2015-03-17 L. Chemin , C. Soubiran , F. Crifo , G. Jasniewicz , L. Veltz , D. Hestroffer , S. Udry , J. Berthier , A. Vigneron , D. Katz , A. Siebert

Various dedicated satellite projects are underway or in advanced stages of planning to perform high-precision, long duration time series photometry of stars, with the purpose of using the frequencies of stellar oscillations to put new…

Astrophysics · Physics 2009-11-07 Frank P. Pijpers

We describe a new software package capable of predicting the spectra of solar-system planets, exoplanets, brown dwarfs and cool stars. The Versatile Software for Transfer of Atmospheric Radiation (VSTAR) code combines a line-by-line…

Earth and Planetary Astrophysics · Physics 2015-05-30 Jeremy Bailey , Lucyna Kedziora-Chudczer

Convection plays an essential role in the emerging intensity for many stars that will be observed by Gaia. Convective-related surface structures affect the shape, shift, and asymmetry of absorption lines, the phocentric and photometric…

Solar and Stellar Astrophysics · Physics 2011-12-13 A. Chiavassa , L. Bigot , F. Thevenin , R. Collet , G. Jasniewicz , Z. Magic , M. Asplund

In this paper we present a detailed spectroscopic analysis of the suspected marginal Am star HD\,71297. Our goal is to test the accuracy of two different approaches to determine the atmospheric parameters effective temperature, gravity,…

Solar and Stellar Astrophysics · Physics 2015-06-15 G. Catanzaro , V. Ripepi , H. Bruntt

The ~ 200,000 stars observed by the Kepler mission have provided unprecedented constraints across astrophysics. With the advent of modern spectroscopic and photometric surveys, new limits in stellar characterizations are within reach. In…

Solar and Stellar Astrophysics · Physics 2026-03-20 Diego Godoy-Rivera , Desmond H. Grossmann , Tyler Richey-Yowell , Angela R. G. Santos , Savita Mathur , Rafael A. Garcia

This paper investigates the problem of estimating three stellar atmospheric physical parameters and thirteen elemental abundances for medium-resolution spectra from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Typical…

Solar and Stellar Astrophysics · Physics 2023-12-27 Xiangru Li , Xiaoyu Zhang , Shengchun Xiong , Yulong Zheng , Hui Li

We present some of the strategies being developed to classify and parameterize objects obtained with spectra from the Sloan Digital Sky Survey (SDSS) and the RAdial Velocity Experiment (RAVE) and present some results. We estimate stellar…

Astrophysics · Physics 2008-11-13 P. Re Fiorentin , C. A. L. Bailer-Jones , T. C. Beers , T. Zwitter , Y. S. Lee , X. -X. Xue

We present a database of 45,000 atmospheric models (which will become 80,000 models by the end of the project) with stellar masses between 9 and 120 M$_{\odot}$, covering the region of the OB main sequence and W-R stars in the H-R diagram.…

Understanding the atmospheric parameters of stars on the top of the RGB is essential to reveal the chemical composition of the Milky Way, as they can be used to probe the farthest parts of our Galaxy. Our goal is to determine the chemical…

Solar and Stellar Astrophysics · Physics 2024-04-23 Z. Dencs , A. Derekas , T. Mitnyan , M. F. Andersen , B. Cseh , F. Grundahl , V. Hegedűs , J. Kovács , L. Kriskovics , P. L. Palle , A. Pál , L. Szigeti , Sz. Mészáros

Spectral retrieval has long been a powerful tool for interpreting planetary remote sensing observations. Flexible, parameterised, agnostic models are coupled with inversion algorithms in order to infer atmospheric properties directly from…

Earth and Planetary Astrophysics · Physics 2020-07-08 Joanna K. Barstow , Kevin Heng

Doppler imaging spectroscopy is the most reliable way to directly measure wind speeds of planetary atmospheres of the Solar system. However, most knowledge about atmospheric dynamics has been obtained with cloud-tracking technique, which…

Earth and Planetary Astrophysics · Physics 2019-06-14 Patrick Gaulme , Francois-Xavier Schmider , Ivan Goncalves

Gaia is a satellite mission of the ESA, aiming at absolute astrometric measurements of about one billion stars (all stars down to 20th magnitude, with unprecedented accuracy. Additionally, magnitudes and colors will be obtained for all…

Astrophysics · Physics 2008-12-18 Stefan Jordan

To date, we have access to enormous inventories of stellar spectra that allow the extraction of atmospheric parameters and chemical abundances essential in stellar studies. However, characterizing such a large amount of data is complex and…

Measurements of radial velocity variations from the spectroscopic monitoring of stars and their companions are essential for a broad swath of astrophysics, providing access to the fundamental physical properties that dictate all phases of…

Mass is the most important stellar parameter, but it is not directly observable for a single star. Spherical model stellar atmospheres are explicitly characterized by their luminosity ($L_\star$), mass ($M_\star$) and radius ($R_\star$),…

Solar and Stellar Astrophysics · Physics 2015-06-15 John B. Lester , Rayomond Dinshaw , Hilding R. Neilson

In its all-sky survey, the ESA global astrometry mission Gaia will perform high-precision astrometry and photometry for 1 billion stars down to $V = 20$ mag. The data collected in the Gaia catalogue, to be published by the end of the next…

Earth and Planetary Astrophysics · Physics 2015-05-14 A. Sozzetti

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

The fast classification of new variable stars is an important step in making them available for further research. Selection of science targets from large databases is much more efficient if they have been classified first. Defining the…

Astrophysics · Physics 2009-11-13 J. Debosscher , L. M. Sarro , C. Aerts , J. Cuypers , B. Vandenbussche , R. Garrido , E. Solano