Related papers: Variable Red Giants Exploration with MASTER Roboti…
The structure and kinematics of the Milky Way disk are largely inferred from the solar vicinity. To gain a comprehensive understanding, it is essential to find reliable tracers in less-explored regions like the bulge and the far side of the…
We have used many decades of visual observations from the AAVSO International Database, and the AAVSO time-series analysis package VSTAR, to study the long-term changes in period, amplitude, and mean magnitude in about 30 normal pulsating…
Observational arguments supporting the binary explanation of the long secondary periods (LSP) phenomenon in red giants are presented. Photometry of about 1200 semiregular variables with the LSP in the Large Magellanic Cloud are analyzed…
The detection of oscillations with a mixed character in subgiants and red giants allows us to probe the physical conditions in their cores. With these mixed modes, we aim at determining seismic markers of stellar evolution. Kepler…
I present a selection of results obtained from VLT FORS1 and ISAAC photometric monitoring of late-type giants in NGC 5128 (=Centaurus A). The combination of optical and near-IR photometry allows to probe the full metallicity range of the…
Context. The advent of space-borne missions such as CoRoT or Kepler providing photometric data has brought new possibilities for asteroseismology across the H-R diagram. Solar-like oscillations are now observed in many stars, including red…
I present details of the variations of several hundred red giant stars on time scales of a few hours to a few days from Hubble Space Telescope (HST) observations of a low-extinction galactic bulge sample from an intensive seven day…
In this paper, we report the detections of stellar variabilities from the first 2-year observations of sky area of about 1300 square degrees from the Tsinghua University-NAOC Transient Survey (TNTS). A total of 1237 variable stars…
The stellar evolution theory of massive stars remains uncalibrated with high-precision photometric observational data mainly due to a small number of luminous stars that are monitored from space. Automated all-sky surveys have revealed…
We establish a sample of 370 Mira variables that are likely near the Galactic center (GC). The sources have been selected from the OGLE and BAaDE surveys based on their sky coordinates, OGLE classifications, and BAaDE maser-derived…
Context. The EROS-2 survey has produced a database of millions of time series from stars monitored for more than six years, allowing to classify some of their sources into different variable star types. Among these, Long Period Variables…
The times of maximum brightness collected in the GEOS RR Lyr database allowed us to trace the period variations of a sample of 123 galactic RRab variables. These data span a time baseline exceeding 100 years. Clear evidence of period…
We have observed and spatially resolved a set of seven A-type stars in the nearby Ursa Major moving group with the Classic, CLIMB, and PAVO beam combiners on the CHARA Array. At least four of these stars have large rotational velocities ($v…
Solar-like oscillations in red giants have been investigated with CoRoT and Kepler, while pulsations in more evolved M giants have been studied with ground-based microlensing surveys. After 3.1 years of observation with Kepler, it is now…
Due to their transitionary nature, yellow supergiants provide a critical challenge for evolutionary modeling. Previous studies within M31 and the SMC show that the Geneva evolutionary models do a poor job at predicting the lifetimes of…
Many decades ago a search for variable stars was one of the main areas of astrophysical research. Such searches, conducted with CCD detectors rather than with photographic plates, became a by-product of several projects seeking…
We have used systematic, sustained visual observations from the AAVSO International Database, and the AAVSO time-series analysis package VSTAR to study the unexplained "long secondary periods" (LSPs) in 27 pulsating red giants. In our…
We describe a methodology to classify periodic variable stars identified using photometric time-series measurements constructed from the Wide-field Infrared Survey Explorer (WISE) full-mission single-exposure Source Databases. This will…
The All-Sky Automated Survey for Supernovae (ASAS-SN) provides long baseline (${\sim}4$ yrs) $V-$band light curves for sources brighter than V$\lesssim17$ mag across the whole sky. We produced V-band light curves for a total of ${\sim}61.5$…
Variable stars with well-calibrated period-luminosity relationships provide accurate distance measurements to nearby galaxies and are therefore a vital tool for cosmology and astrophysics. While these measurements typically rely on samples…