Related papers: A high-resolution spectroscopic survey of late-typ…
We present the results of a study of young unresolved stellar groupings (clusters, OB associations, and their complexes) associated with HII regions, based on the coupling of spectroscopic, photometric and H{\alpha} spectrophotometric…
Stellar activity cycles are known to be a widespread phenomenon amongst moderately active solar- and late-type stars from long-term periodic variations in chromospheric Ca II H and K emission lines, yet to date only a handful of coronal…
We present a spectroscopic analysis of nearly 8000 late-type dwarfs in the Sloan Digital Sky Survey. Using the Halpha emission line as an activity indicator, we investigate the fraction of active stars as a function of spectral type and…
We present a spectroscopic survey of galaxies in the COSMOS field using the Fiber Multi-Object Spectrograph (FMOS), a near-infrared instrument on the Subaru Telescope. Our survey is specifically designed to detect the Halpha emission line…
We present a technique to extract radial velocity measurements from echelle spectrograph observations of rapidly rotating stars ($V\sin{i} \gtrsim 50$ km s$^{-1}$). This type of measurement is difficult because the line widths of such stars…
The rotation-activity connection is the standard paradigm for interpreting chromospheric and coronal activity in late-type stars, namely, stars with outer convection zones. This paradigm states that activity increases with decreasing…
Using precise measurements of the helium D3 line, we have searched for statistically significant variations in the strength of chromospheric activity in 13 early F-type stars and two late F-type stars. In two early F-type stars, we find…
Stellar rotation is a crucial parameter driving stellar magnetism, activity and mixing of chemical elements. Furthermore, the evolution of stellar rotation is coupled to the evolution of circumstellar disks. Disk-braking mechanisms are…
This paper describes a multiwavelengh optical study of chromospheres in two X-ray/EUV selected active binary stars with strong H_alpha emission, V789 Mon (2RE J0725-002) and GZ Leo (2RE J1101+223). The goal of the study is to determine…
Activity studies of solar-type stars, especially with reference to the status of our current Sun among them, have exposed the importance of (1) homogeneously selecting the sample stars and (2) reliably evaluating their activities down to a…
Abridged: We have used the well-selected sample of ~1750 embedded, young, massive stars identified by the RMS survey to investigate the Galactic distribution of recent massive star formation. We describe the various methods used to assign…
We derive stellar parameters and abundances (`stellar labels') of 40,034 late-B and A-type main-sequence stars extracted from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope Medium Resolution Survey (LAMOST--MRS). The primary…
We have used archival Hubble Space Telescope observations obtained with the Advanced Camera for Surveys to study the H{\alpha} emission properties of main sequence stars in the globular cluster 47 Tucanae. Using a combination of multi-band…
In this paper we present a spectroscopic study of six double-lined binaries, five of which were recently discovered in a high-resolution spectroscopic survey of optical counterparts of stellar X-ray sources. Thanks to high-resolution…
Extra-solar planet search programs require high-precision velocity measurements. They need to study how to disentangle radial-velocity variations due to Doppler motion from the noise induced by stellar activity. We monitored the active K2V…
Observations of various solar-type stars along decades revealed that they can have magnetic cycles, just like our Sun. An investigation of the relation between their cycle length and rotation period can shed light on the dynamo mechanisms…
During the course of a large spectroscopic survey of X-ray active late-type stars in the solar neighbourhood, we discovered four lithium-rich stars packed within just a few degrees on the sky. These very young stars are projected several…
The ensemble of chemical element abundance measurements for stars, along with precision distances and orbit properties, provides high-dimensional data to study the evolution of the Milky Way. With this third data release of the Galactic…
Kepler ultra-high precision photometry of long and continuous observations provides a unique dataset in which surface rotation and variability can be studied for thousands of stars. Because many of these old field stars also have…
Over the next decade, observations conducted with ALMA and the SKA will reveal the process of mass assembly and accretion onto young stars and will be revolutionary for studies of star formation. Here we summarise the capabilities of ALMA…