Related papers: Relation between spectral indices and binary fract…
We present a spectroscopic survey of the stellar population of the Sigma Orionis cluster. We have obtained spectral types for 340 stars. Spectroscopic data for spectral typing come from several spectrographs with similar spectroscopic…
I present an atlas of near-infrared K-band spectra of 31 late-type giants and supergiants, and two carbon stars. The spectra were obtained at resolving powers of 830 and 2000, and have a signal-to-noise ratio of 100 or higher. These data…
We use near-infrared spectroscopic data from the inner few hundred parsecs of a sample of 47 active galaxies to investigate possible correlations between the stellar velocity dispersion (sigma_star), obtained from the fit of the K-band CO…
We have identified the H-alpha absorption feature as a new spectroscopic diagnostic of luminosity class in K- and M-type stars. From high-resolution spectra of 19 stars with well-determined physical properties (including effective…
Spectroscopic measurements of Mira variable stars, as a function of phase, probe the stellar atmospheres and underlying pulsation mechanisms. For example, measuring variations in TiO, VO, and ZrO with phase can be used to help determine…
The majority of massive classical Be stars are thought to be binary interactions products. Their rapid rotation and often strong, variable, and emission-line dominated spectrum, make spectroscopic analysis challenging. Hence, robust binary…
Our goal is to provide a quantification of several spectral classification criteria for O stars. We collected high-spectral resolution spectra of 105 Galactic O-type stars from various archives. We measured equivalent widths of…
The masses of stars and planets can be measured dynamically in binary systems. For an unresolved binary, time series astrometry yields some orbital parameters, but it cannot provide the component masses, because we observe only the motion…
Young, massive stars dominate the rest-frame ultraviolet spectra of star-forming galaxies. At high redshifts (z>2), these rest-UV features are shifted into the observed-frame optical and a combination of gravitational lensing, deep…
Context. Blue Stragglers Stars (BSSs) are thought to form in globular clusters by two main formation channels: i) mergers induced by stellar collisions and ii) coalescence or mass-transfer between companions in binary systems. The detailed…
Using our new Binary Population and Spectral Synthesis (BPASS) code we explore the affect of binary populations on the integrated spectra of galaxies. We also explore the interplay of binary populations and a varying maximum stellar mass.…
The analysis of solar-like oscillations for stars belonging to a binary system provides a unique opportunity to probe the internal stellar structure and to test our knowledge of stellar physics. Such oscillations have been recently observed…
The leading method for the determination of relevant stellar population parameters of unresolved extragalactic Globular Clusters is through the study of their integrated spectroscopy, where Balmer line-strength indices are considered to be…
The fundamental parameters of a low-mass star can potentially be determined from its photometry and astrometry. This is complicated by the fact that 10-20 percent of low-mass stars are predicted to be equal-mass binaries. These unresolved…
Binary fraction and orbital characteristics provide indications on the conditions of star formation, as they shed light on the environment they were born in. Multiple systems are more common in low density environments rather than in higher…
We study spectral diagnostics available from optical spectra with R=17000 obtained with the VLT/Giraffe HR15n setup, using observations from the Gaia-ESO Survey, on the gamma Vel young cluster, in order to determine the fundamental…
Measuring the frequency of binary stars in dwarf spheroidal galaxies (dSphs) requires data taken over long time intervals. We combine radial velocity measurements from five literature sources taken over the course of ~30 years to yield the…
Many field stars reside in binaries, and the analysis and interpretation of photometric and spectroscopic surveys must take this into account. We have developed a model to predict how binaries influence the scientific results inferred from…
In this study we investigate the calibration of surface brightness--color (SBC) relations based solely on eclipsing binary stars. We selected a sample of 35 detached eclipsing binaries with trigonometric parallaxes from Gaia DR1 or…
The Lick-index spectrophotometric system is investigated in its inherent statistical and operational properties to ease a more appropriate use for astrophysical studies. Non-Gaussian effects in the index standardization procedure suggest…