Related papers: The PTI Carbon Star Angular Size Survey: Effective…

Context. Sunlight scattered from the surface of an airless body is generally partially polarized, and the corresponding polarization state includes information about the scattering surface, such as albedo, surface grain sizes, composition,…

We present optical nanoantennas designed for applications that require processing temperatures larger than 800{\deg}C. The antennas consist of arrays of Re/Pt bilayer strips fabricated with a lift-off-free technique on top of etched…

Based on our prior accurate determination of fundamental parameters for 36 Galactic A-, F- and G-type supergiants and bright giants (luminosity classes I and II), we undertook a non-LTE analysis of the carbon abundance in their atmospheres.…

A solar photospheric "thermal profiling" analysis is presented, exploiting the infrared rovibrational bands of carbon monoxide (CO) as observed with the McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above the…

We present detailed chemical analyses for a sample of twelve stars selected from the CH star catalogue of Bartkevicius (1996). The sample includes two confirmed binaries, four objects that are known to show radial velocity variations and…

We perform a study of 62 solar analog stars to compute their effective temperatures (Teff) using the Balmer line wing fitting procedure and compare them with Teff values obtained using other commonly employed methods. We use observed…

Interferometric radius measurements provide a direct probe of the fundamental parameters of M dwarfs, but is within reach for only a limited sample of nearby, bright stars. We use interferometrically-measured radii, bolometric luminosities,…

Large spectroscopic surveys of the Milky Way need to be calibrated against a sample of benchmark stars to ensure the reliable determination of atmospheric parameters. We present new fundamental stellar parameters of seven giant and subgiant…

We present here quantitative diagnostic tools for cool giants that employ low-resolution near-infrared spectroscopy in the $K$-band for stellar population studies. In this study, a total of 260 cool giants (177 stars observed with X-shooter…

RAVE, the unbiased magnitude limited survey of the southern sky stars, contained 456,676 medium-resolution spectra at the time of our analysis. Spectra cover the CaII IRT range which is a known indicator of chromospheric activity. Our…

The effective temperature, one of the most fundamental atmospheric parameters of a star, can be estimated using various methods, and here we focus on the method using line-depth ratios (LDRs). This method combines low- and high-excitation…

In this paper, we present the measurement of the energy spectra of carbon and oxygen in cosmic rays based on observations with the Calorimetric Electron Telescope (CALET) on the International Space Station from October 2015 to October 2019.…

We report new results of our search for rare, cool carbon stars located at large distances from the galactic plane. Eighteen new C stars were discovered. Six are remarkable by showing the two peculiarities of a strong infrared excess at 12…

IRC +10216 is the prototypical carbon star exhibiting an extended molecular circumstellar envelope. Its spectral properties are therefore the template for an entire class of objects. The main goal is to systematically study the $\lambda$…

A number of empirical correlations that allows us to calculate the effective temperature and surface gravity for a set evolved post-AGB and RV Tauri stars are determined using as calibrators the intrinsic colours of 2MASS (Two Micron All…

The technique of line depth ratios (LDR) is one of the methods to determine the effective temperature of a star. They are crucial in the spectroscopic studies of variable stars like Cepheids since no simultaneous photometry is usually…

The eclipsing binary LL Aqr is a bright V = 9.32, detached system consisting of two solar-type stars in an eccentric orbit (P = 20.2 d). The secondary component, LL Aqr B, was previously found to have physical and atmospheric parameters…

We have analysed the photometric data obtained with the STEREO spacecraft for 558 non-magnetic chemically peculiar (CP) stars to search for rotational and pulsational variability. Applying the Lomb-Scargle and the phase dispersion…

We report the latest statistical analyses of superflares on solar-type (G-type main-sequence; effective temperature is 5100 - 6000 K) stars using all of the $Kepler$ primary mission data, and $Gaia$-DR2 (Data Release 2) catalog. We updated…

The CoRoT faint stars channel observed about 163 600 targets to detect transiting planetary companions. Because CoRoT targets are faint (11< r <16) and close to the galactic plane, only a small subsample has been observed spectroscopically.…