Related papers: A Relationship Between Stellar Age and Spot Covera…
(abbreviated) We report detection with the Spitzer Space Telescope of cool dust surrounding solar type stars. The observations were performed as part of the Legacy Science Program, ``Formation and Evolution of Planetary Systems'' (FEPS).…
The results of an optical spectroscopic survey of a sample of young stellar objects (YSOs) and pre-main sequence (PMS) stars in the Lupus Clouds are presented. 92 objects were observed with VLT/FLAMES. All of those objects show IR excess as…
We present a detailed spatial analysis of stellar populations based on long-slit optical spectra in a sample of eight luminous early-type galaxies selected from nearby sparse groups and pairs, three of them may be interacting with a galaxy…
Large exoplanet surveys have successfully detected thousands of exoplanets to-date. Utilizing these detections and non-detections to constrain our understanding of the formation and evolution of planetary systems also requires a detailed…
We investigate the precision of the ages and metallicities of 21,000 mock simple stellar populations (SSPs) determined through full-spectrum fitting. The mock SSPs cover an age range of 6.8 $<$ log (age/yr) $<$ 10.2, for three wavelength…
Wide-field high-precision photometric observations such as \textit{Transiting Exoplanet Survey Satellite (TESS)} allowed the investigation of the stellar magnetic activity of cool stars. M-dwarf's starspots and stellar flares are the main…
We present an analytic model of the lightcurve variation for stars with non-evolving starspots on a differentially rotating surface. The Fourier coefficients of the harmonics of the rotation period are expressed in terms of the latitude of…
We utilize the data from the Apache Point Observatory Galactic Evolution Experiment-2 (APOGEE-2) in the fourteenth data release of the Sloan Digital Sky Survey (SDSS) to calculate the line-of-sight velocity dispersion $\sigma_{1D}$ of a…
The variations of kinematic parameters with age are considered for a sample of 15 402 thin-disk O--F stars with accurate $\alpha$, $\delta$, $\mu$, and $\pi>3$ mas from the Hipparcos catalogue and radial velocities from the PCRV catalogue.…
20573 simulations of planetary transits around spotted stars were conducted using the transit-starspot model, \texttt{PRISM}. In total 3888 different scenarios were considered using three different host star spectral types, M4V, M1V and…
Spectral energy distributions are presented for 94 young stars surrounded by disks in the Serpens Molecular Cloud, based on photometry and Spitzer IRS spectra. Taking a distance to the cloud of 415 pc rather than 259 pc, the distribution of…
We report on a new method for tracking the phases of the orbital modulations in very short-period, near-contact, and contact binary systems systems in order to follow starspots. We apply this technique to Kepler light curves for 414 binary…
We derive the Sun's offset from the local mean Galactic plane($z_\odot$) using the observed $z$ distribution of young pulsars. Pulsar distances are obtained from measurements of annual parallax, HI absorption spectra or associations where…
Asteroseismology provides powerful means to probe stellar interiors. The oscillations frequencies are closely related to stellar interior properties via the density and sound speed profiles. Since these are tightly linked with the mass and…
We explore methods to improve the estimates of star formation rates and mean stellar population ages from broadband photometry of high redshift star-forming galaxies. We use synthetic spectral templates with a variety of simple parametric…
We introduce SPARC (Spitzer Photometry & Accurate Rotation Curves): a sample of 175 nearby galaxies with new surface photometry at 3.6 um and high-quality rotation curves from previous HI/Halpha studies. SPARC spans a broad range of…
We investigate the distribution of bright main sequence stars near the northern edge of the M33 disk. Clustering on sub-kpc scales is seen among stars with ages near 10 Myr, and two large star-forming complexes are identified. Similar…
A recent JHKs study of several grand-design spiral galaxies shows a bimodal distribution of their system of star clusters and star forming complexes in colour-magnitude and colour-colour diagrams. In a comparison with stellar population…
We combine stellar surface rotation periods determined from NASA's Kepler mission with spectroscopic temperatures to demonstrate the existence of pileups at the long-period and short-period edges of the temperature-period distribution for…
Context. Most stars form in clusters or associations but only a small number of these groups are expected to remain bound for longer than a few Myr. Once star formation has ended and the molecular gas around young stellar objects has been…