相关论文: Synthetic spectra for O and B type subdwarf stars

Quantitative spectroscopy of luminous BA-type supergiants offers a high potential for modern astrophysics. The degree to which we can rely on quantitative studies of this class of stars as a whole depends on the quality of the analyses for…

We have revisited and updated the $uvby$ Str\"omgren colour and colour-index distributions of A, F and early G-type main sequence stars. For this aim, we selected 7054 dwarf stars along with 65 MK standard stars within the same spectral…

We present a panoramic atlas of Spitzer/IRS spectra of extragalactic sources collected from the recent literature, with value added measurements of their spectral features obtained in a homogeneous and concise manner. The atlas covers the…

X-ray grating observations have revealed great detail in the spectra of Novae in the Super Soft Source (SSS) phase. Notable features in the SSS spectra are blue-shifted absorption lines, P-Cygni line profiles, and the absence of strong…

We carried out a critical appraisal of the two theoretical models, Kurucz' ATLAS9 and PHOENIX/NextGen, for stellar atmosphere synthesis. Our tests relied on the theoretical fit of SEDs for a sample of 334 target stars along the whole…

A high-resolution ($\sim$45000), high signal-to-noise ($>$100) K-band spectral atlas of massive stars is presented. It includes 81 stars consisting of known optical standards, spanning spectral and luminosity subclasses from O2 to O9, and…

We determined the silicon abundances of 253 metal-poor stars in the metallicity range $-4<\mathrm{[Fe/H]} <-1.5$, based on non-local thermodynamic equilibrium (NLTE) line formation calculations of neutral silicon and high-resolution spectra…

A previously-described code for constructing moving reversing layers (MRL) is improved by replacing a two-parameter model for the radiative acceleration due to lines with a flexible non-parametric description, thus allowing a greater degree…

We study the implications of averaging methods with different reference depth scales for 3D hydrodynamical model atmospheres computed with the Stagger-code. The temporally and spatially averaged (hereafter denoted as <3D>) models are…

We present an abundance analysis of the far-ultraviolet (905--1187 A) spectrum of the subdwarf B star PG0749+658, obtained by the Far Ultraviolet Spectroscopic Explorer (FUSE). The data have a resolution of about R = lambda / Delta lambda =…

With the advent of large spectroscopic surveys, automated stellar parameter determination has become commonplace. Nevertheless, spectral classification still offers a quick and useful alternative for obtaining parameter estimates for large…

Photospheric C, N, and O abundances of 118 solar-analog stars were determined by applying the synthetic-fitting analysis to their spectra in the blue or near-UV region comprising lines of CH, NH, and OH molecules, with an aim of clarifying…

222 hot subdwarf stars were identified with LAMOST DR8 spectra, among which 131 stars show composite spectra and have been decomposed, while 91 stars present single-lined spectra. Atmospheric parameters of all sample stars were obtained by…

We present atmospheric parameters for 51 nearby FG dwarfs uniformly distributed over the -2.60 < [Fe/H] < +0.20 metallicity range that is suitable for the Galactic chemical evolution research. Lines of iron, Fe I and Fe II, were used to…

Young stars with masses 2-8 Suns, called the Herbig Ae and Be stars, often show a near-infrared excess too large to explain with a hydrostatically-supported circumstellar disk of gas and dust. At the same time the accretion flow carrying…

We provide a grid of PHOENIX spectra of red giant and supergiant stars, that extend through optical and near-IR wavelengths. For the first time, models are also provided with modified surface abundances of C, N and O, as a step towards…

A library of 183588 synthetic spectra based on Kurucz's ATLAS9 models is presented for the far red spectral interval (7653 -- 8747\AA). It is characterized by 3500 K <= T_eff <= 47500 K, 0.0 <= log g <= 5.0, -3.0 <= [M/H] <= +0.5, 0 <=…

We present intermediate resolution (R ~ 8,000 - 12,000) high signal-to-noise H- and K-band spectroscopy of a sample of 37 optically visible stars, ranging in spectral type from O3 to B3 and representing most luminosity classes. Spectra of…

We present a model-fit pipeline to determine the stellar parameters of M-type dwarfs, which is an improvement upon our previous work described in Hejazi et al. 2020. We apply this pipeline to analyze the low-resolution (R~2000) spectra of…

We present oxygen abundances for 72 F and G dwarf stars in the solar neighbourhood. Using the kinematics of the stars we divide them into two sub-samples with space velocities that are typical for the thick and thin disks, respectively. The…