scholarly journals Stellar Properties of Pre-Main-Sequence Stars from High-Resolution Near-Infrared Spectra

2003 ◽  
Vol 126 (6) ◽  
pp. 3043-3057 ◽  
Author(s):  
G. W. Doppmann ◽  
D. T. Jaffe ◽  
R. J. White
Keyword(s):  
High Resolution ◽  
Infrared Spectra ◽  
Main Sequence ◽  
Near Infrared ◽  
Main Sequence Stars ◽  
Near Infrared Spectra ◽  
Stellar Properties

scholarly journals Anomalous Spectral Types and Intrinsic Colors of Young Stars

2015 ◽  
Vol 10 (S314) ◽  
pp. 85-90 ◽  
Author(s):  
Mark J. Pecaut
Keyword(s):  
Infrared Spectra ◽  
Spectral Type ◽  
Main Sequence ◽  
Near Infrared ◽  
Systematic Errors ◽  
Optical Spectra ◽  
Young Stars ◽  
Main Sequence Stars ◽  
Near Infrared Spectra ◽  
Dynamical Masses

AbstractWe highlight differences in spectral types and intrinsic colors observed in pre-main sequence (pre-MS) stars. Spectral types of pre-MS stars are wavelength-dependent, with near-infrared spectra being 3-5 spectral sub-classes later than the spectral types determined from optical spectra. In addition, the intrinsic colors of young stars differ from that of main-sequence stars at a given spectral type. We caution observers to adopt optical spectral types over near-infrared types, since Hertzsprung-Russell (H-R) diagram positions derived from optical spectral types provide consistency between dynamical masses and theoretical evolutionary tracks. We also urge observers to deredden pre-MS stars with tabulations of intrinsic colors specifically constructed for young stars, since their unreddened colors differ from that of main sequence dwarfs. Otherwise, V-band extinctions as much as ~0.6 mag erroneously higher than the true extinction may result, which would introduce systematic errors in the H-R diagram positions and thus bias the inferred ages.

High-resolution near-infrared spectra of normal and super-metal-rich K giants

1985 ◽  
Vol 90 ◽  
pp. 1349 ◽  
Author(s):  
H. E. Bond ◽  
D. Burstein ◽  
S. M. Faber ◽  
R. E. Luck
Keyword(s):  
High Resolution ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Near Infrared Spectra ◽  
K Giants

scholarly journals Exploring the stellar properties of M dwarfs with high-resolution spectroscopy from the optical to the near-infrared

2018 ◽  
Vol 620 ◽  
pp. A180 ◽  
Author(s):  
A. S. Rajpurohit ◽  
F. Allard ◽  
S. Rajpurohit ◽  
R. Sharma ◽  
G. D. C. Teixeira ◽  
...  
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
Spectral Synthesis ◽  
Model Atmosphere ◽  
High Resolution Spectroscopy ◽  
Cloud Formation ◽  
M Dwarfs ◽  
Near Infrared Spectra ◽  
The Galaxy ◽  
Stellar Properties

Context. Being the most numerous and oldest stars in the galaxy, M dwarfs are objects of great interest for exoplanet searches. The presence of molecules in their atmosphere complicates our understanding of their atmospheric properties. But great advances have recently been made in the modeling of M dwarfs due to the revision of solar abundances. Aims. We aim to determine stellar parameters of M dwarfs using high resolution spectra (R ∼ 90 000) simultaneously in the visible and the near-infrared. The high resolution spectra and broad wavelength coverage provide an unique opportunity to understand the onset of dust and cloud formation at cool temperatures. Furthermore, this study will help in understanding the physical processes which occur in a cool atmospheres, particularly, the redistribution of energy from the optical to the near-infrared. Methods. The stellar parameters of M dwarfs in our sample have been determined by comparing the high resolution spectra both in the optical and in the near-infrared simultaneously observed by CARMENES with the synthetic spectra obtained from the BT-Settl model atmosphere. The detailed spectral synthesis of these observed spectra both in the optical and in the near-infrared helps to understand the missing continuum opacity. Results. For the first time, we derive fundamental stellar parameters of M dwarfs using the high resolution optical and near-infrared spectra simultaneously. We determine Teff, log g and [M/H] for 292 M dwarfs of spectral type M0 to M9, where the formation of dust and clouds are important. The derived Teff for the sample ranges from 2300 to 4000 K, values of log g ranges from 4.5 ≤ logg ≤ 5.5 and the resulting metallicity ranges from −0.5 ≤ [M/H] ≤ +0.5. We have also explored the possible differences in Teff, log g and [M/H] by comparing them with other studies of the same sample of M dwarfs.

High-Resolution Near-Infrared Spectra of Protostars

2000 ◽  
Vol 120 (1) ◽  
pp. 430-436 ◽  
Author(s):  
Thomas P. Greene ◽  
Charles J. Lada
Keyword(s):  
High Resolution ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Near Infrared Spectra

scholarly journals Red and Near Infrared Spectra* of Pre-Main Sequence Stars I. A Preliminary Investigation of T Tauri Stars

1977 ◽  
Vol 42 ◽  
pp. 100-105 ◽  
Author(s):  
Y. Andrillat
Keyword(s):  
Color Index ◽  
Main Sequence ◽  
Near Infrared ◽  
Preliminary Investigation ◽  
Visible Spectrum ◽  
T Tauri Stars ◽  
Main Sequence Stars ◽  
Type K ◽  
T Tauri ◽  
Near Infrared Spectra

230 Å mm-1 spectra of 30 stars of T Tauri or related type were obtained in the 8000-11000 Å region using a grating spectrograph equipped with an S-1 photocathode image-tube. In addition a few T Tauri stars were observed at the same dispersion in the 6200-8800 Å region on IN plate. A preliminary qualitative analysis of the observations leads to possible correlations between the intensities of emissions of the Ca II triplet, Paschen series and He I 10830 Å, and the spectral type, K-L color index of the star, or the [0 I] and Fe II intensities in the visible spectrum.

scholarly journals Physical parameters of T dwarfs derived from high-resolution near-infrared spectra

2009 ◽  
Vol 501 (3) ◽  
pp. 1059-1071 ◽  
Author(s):  
C. del Burgo ◽  
E. L. Martín ◽  
M. R. Zapatero Osorio ◽  
P. H. Hauschildt
Keyword(s):  
High Resolution ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Physical Parameters ◽  
Near Infrared Spectra

scholarly journals Characterizing stellar parameters from high-resolution spectra of main sequence cool stars. I. The G2V–K2V stars

2019 ◽  
Vol 487 (1) ◽  
pp. 1335-1362
Author(s):  
Logithan Kulenthirarajah ◽  
Jean-François Donati ◽  
Gaitee Hussain ◽  
Julien Morin ◽  
France Allard
Keyword(s):  
High Resolution ◽  
Main Sequence ◽  
Near Infrared ◽  
Absolute Accuracy ◽  
Spectral Library ◽  
M Dwarfs ◽  
Near Infrared Spectra ◽  
Cool Stars ◽  
Error Bars ◽  
Good Agreement

Abstract The goal of the present study is to construct, test, and validate a high-resolution synthetic spectral library using PHOENIX model atmospheres and develop a reliable tool to estimate stellar parameters from high-resolution optical and/or near-infrared spectra of M dwarfs. We report here the preliminary results of tests characterizing main sequence G–K stars from high-resolution spectra. We anchored the atomic line-list using the stellar standards Sun, ξ Boo A, and ϵ Eri to ensure the synthetic spectra computed with PHOENIX reproduce their observed counterparts. These stars were chosen because their parameters are very well characterized, and on which the absolute accuracy of our method depends on. We successfully estimated the stellar parameters with associated error bars for 17 stars. Using a pseudo Monte Carlo statistical analysis, we present overall improved uncertainties on the stellar parameters compared to those in the literature (on average 9 K, 0.014 dex, and 0.008 dex for the effective temperature, the surface gravity, and the metallicity, respectively). Our estimated stellar parameters are also in good agreement with values found in the literature.

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