1,153 datasets found

Most M dwarfs present high chromospheric activity that can exceed the solar magnetic activity. This can substantially influence planetary, atmospheric, and biological processes,...

A combination of spectroscopic and photometric observations provides an excellent data sample for studying stellar chromospheric activity. We have combined LAMOST...

We present the stellar parameters and chemical abundances of 30 elements for five stars located at large radii (3.5-10.7 times the half-light radius) in the Sextans dwarf...

We present a spectroscopic analysis of ten carbon enhanced metal-poor (CEMP) stars of type CEMP-s and CEMP-rs and determine their non-local thermodynamic equilibrium (NLTE)...

Eta Carinae ({eta} Car) exhibits a unique set of P Cygni profiles with both broad and narrow components. Over many decades, the spectrum has changed-there has been an increase...

The study of young associations is essential for building a complete record of local star formation processes. The Fornax-Horologium association (FH), including the {chi}1...

We present an investigation into the rotation and stellar activity of four fully convective M dwarf "twin" wide binaries. Components in each pair have (1) astrometry confirming...

Based on echelle spectra obtained at the prime focus of the 6-m telescope, the detailed chemical composition of one of the components of the bipolar nebula identified with the...

Based on high-dispersion echelle spectra taken with the 6-m telescope, detailed chemical composition of the IR source IRAS 20004+2955 identified with the variable star V1027 Cyg...

We study the spatially resolved star formation history (SFH) and molecular gas distribution of 58 nearby galaxies, using integral field spectroscopy from the CALIFA survey and...

Identifying and characterizing young stars in the Solar neighbourhood is essential to find and describe planets in the early stages of their evolution. This work seeks to...

Radial-velocity observations made on more than a thousand nights are presented for the type star of the R Coronae Borealis (RCB) class. There are four principal sources: the...

We have undertaken a comprehensive search for both Lyman alpha emitters (LAEs) and Lyman break galaxies (LBGs) in the Survey for High-z Absorption Red and Dead Sources (SHARDS)...

We present the results of our automatic search for proximate damped Ly{alpha} absorption (PDLA) systems in the quasar spectra from the Sloan Digital Sky Survey Data Release 12....

Deep narrow-band surveys have revealed a large population of faint Ly{alpha} emitters (LAEs) in the distant Universe, but relatively little is known about the most luminous...

We use the LAMOST spectra of member stars in Pleiades, M34, Praesepe, and Hyades to study how chromospheric activity varies as a function of mass and rotation at different age....

We present and explore deep narrow- and medium-band data obtained with the Subaru and the Isaac Newton Telescopes in the ~2deg^2^ COSMOS field. We use these data as an extremely...

It is widely believed that the cool gas clouds traced by MgII absorption, within a velocity offset of 5000km/s relative to the background quasar are mostly associated with the...

Broad absorption lines (BALs) found in a significant fraction of quasar spectra identify high-velocity outflows that might be present in all quasars and could be a major factor...

We investigate broad absorption line (BAL) disappearance and emergence using a 470 BAL-quasar sample over <=0.10-5.25 rest-frame years with at least three spectroscopic...