Related papers: Updates on the Pulsating SdB Star Feige 48 through…

Aims. This study aims to determine the level and constancy of the Spite plateau as definitively as possible from homogeneous high-quality VLT-UVES spectra of 19 of the most metal-poor dwarf stars known. Methods. Our high-resolution (R ~…

We report the discovery of pulsations in the spectroscopic PG 1159 type pre-white dwarf SDSS J075415.12+085232.18. Analysis of the spectrum by Werner, Rauch and Kepler (2014) indicated Teff=120 000+/-10 000 K, log g=7.0+/-0.3, mass…

Spectral analysis needs the observation of lines of successive ionization stages in order to evaluate the ionization equilibrium (of a particular species) which is a sensitive indicator for the effective temperature. Since stars with…

We have revisited the sdB+K-star long-period binary PG 1018-047 based on 20 new high-resolution VLT/UVES spectra that provided regular coverage over a period of more than 26 months. We refine the period and establish that the orbit is…

We report the discovery of four new pulsating subdwarf B (sdBV) stars from Campaign 7 of the Kepler spacecraft's K2 mission. EPICs 215776487, 217280630, 218366972, and 218717602 are all gravity (g)-mode pulsators and we also detect two…

We report the discovery of a low-mass companion orbiting the metal-rich, main sequence F star TYC 2949-00557-1 during the MARVELS (Multi-object APO Radial Velocity Exoplanet Large-area Survey) Pilot Project. The host star has an effective…

Large numbers of low-to-medium resolution spectra of M-type dwarf stars from both the local Galactic disk and halo are available from various surveys. In order to fully exploit these data, we develop a template-fit method using a set of…

The archival spectrum of SDSSJ212531.92-010745.9 shows not only the typical signature of a PG1159 star, but also indicates the presence of a companion. Our aim was the proof of the binary nature ofthis object and the determination of its…

A 2014 study of the eclipsing binary star 1SWASPJ011351.29+314909.7 (J0113+31) reported an unexpectedly high effective temperature for the M-dwarf companion to the 0.95-M$_{\odot}$ primary star. The effective temperature inferred from the…

The optical spectrum of the cubic helimagnetic metal FeGe has been investigated in the frequency range from 0.01 - 3.1 eV for different temperatures from 30 K to 296 K. The optical conductivity shows the evolution of a low energy (0.22 eV)…

We present the discovery of the Kepler-19 planetary system, which we first identified from a 9.3-day periodic transit signal in the Kepler photometry. From high-resolution spectroscopy of the star, we find a stellar effective temperature…

We studied the well known circumstellar disk around the Herbig Ae/Be star HD 97048 with high angular resolution to reveal undetected structures in the disk, which may be indicative of disk evolutionary processes such as planet formation. We…

We attempt to construct a B-V colour temperature relation for stars in the least model dependent way employing the best modern data. The fit we obtained with the form Teff = Teff((B-V)0,[Fe/H],log g) is well constrained and a number of…

The SEGUE survey obtained 240,000 moderate resolution (R = 1800) spectra from 3900 - 9000 Angstroms of fainter Milky Way stars (14.0 < g < 20.3) of a wide variety of spectral types, both main sequence and evolved objects, with the goal of…

We present $Spitzer$ IRS 5--14 $\mu$m spectra and 16 $\mu$m and 22 $\mu$m photometry of the T2.5 companion to the $\sim$300 Myr-old G0V star HN Peg. We incorporate previous 0.8--5 $\mu$m observations to obtain the most comprehensive…

We present a LTE model atmosphere analysis of the medium and long wavelength spectrum of the cool DO white dwarf HD149499B. This observation in the spectral range 230-700 A supplements a previous analysis of an ORFEUS spectrum between 912…

We present a detailed spectroscopic study of 93 solar-type stars that are targets of the NASA/Kepler mission and provide detailed chemical composition of each target. We find that the overall metallicity is well-represented by Fe lines.…

We conducted high dispersion spectroscopic observations of 50 superflare stars with Subaru/HDS, and measured the stellar parameters of them. These 50 targets were selected from the solar-type (G-type main sequence) superflare stars that we…

We present the discovery and asteroseismic analysis of a new g-mode hot B subdwarf (sdB) pulsator, EC 21494-7018 (TIC 278659026), monitored in TESS first sector using 120-second cadence. The light curve analysis reveals that EC 21494-7018…

We present metallicities derived from a sample of eleven M dwarfs belonging to wide binary systems with warmer FG primary companions observed by the high-resolution (R=22,500) near-infrared SDSS-IV APOGEE spectra. Using a plane-parallel…