相关论文: gamma Doradus pulsation in two pre-main sequence s…

Previous studies have reported the existence of two counter-rotating stellar disks in the early-type spiral galaxy NGC7217. We have obtained high-resolution optical spectroscopic data (R ~ 9000) with the new fiber-based Integral Field Unit…

Two main scenarios have been proposed for origin of massive runaway stars -- dynamical ejection or release from a binary at the first core collapse -- but their relative contribution remains debated. Using two large spectroscopic campaigns…

We identify delta Scuti pulsators amongst members of the recently-discovered Cep--Her Complex using light curves from the Transiting Exoplanet Survey Satellite (TESS). We use Gaia colours and magnitudes to isolate a subsample of provisional…

Using high-cadence observations from the Zwicky Transient Facility at low Galactic latitudes, we have discovered a new class of pulsating, hot, compact stars. We have found four candidates, exhibiting blue colors ($g-r\leq-0.1$ mag),…

We have explored a sample of suspected A-type binaries in a systematic way, both spectroscopically and photometrically. Due to their location in the H-R diagram, indications of pulsation and/or chemical peculiarities among these suspected…

Context: Active M dwarfs frequently exhibit large flares, which can pose an existential threat to the habitability of any planet in orbit in addition to making said planets more difficult to detect. M dwarfs do not lose angular momentum as…

We present observations of fields containing eight recently discovered binary millisecond pulsars using the telescopes at MDM Observatory. Optical counterparts to four of these systems are detected, one of which, PSR J2214+3000, is a novel…

We report a photometric and asteroseismic analysis of KIC 3868420, a newly identified high-amplitude $\delta$ Scuti-$\gamma$ Doradus hybrid star located in the Hertzsprung gap - a short-lived and rarely observed post-main-sequence phase.…

A small fraction of red dwarfs younger than 100 million years show structured, periodic optical light curves suggestive of transiting opaque material that corotates with the star. However, the composition, origin, and even the existence of…

We revisit the published analyses of ROSAT X-ray observations of the star forming regions NGC 2264 and Chamaeleon I (~3 and ~5 Myr old respectively) in the light of newly published optical data. At odds with previous results on Chamaeleon I…

Intermediate mass Pre-main sequence stars (1.5 $M_{\odot}< M < 5M_{\odot}$) cross the instability strip on their way to the main sequence. They are therefore expected to be pulsating in a similar way as the $\delta$ Scuti stars. In this…

The timescale of cluster formation is an essential parameter in order to understand the formation process of star clusters. Pre-main sequence (PMS) stars in nearby young open clusters reveal a large spread in brightness. If the spread were…

$Context.$ Pulsating stars are windows to the physics of stars enabling us to see glimpses of their interior. Not all stars pulsate, however. On the main sequence, pulsating stars form an almost continuous sequence in brightness, except for…

Pulsating extremely low-mass pre-white dwarf stars (pre-ELMV), with masses between ~0.15 Msun and ~0.30 Msun, constitute a new class of variable stars showing g- and possibly p-mode pulsations with periods between 320 and 6000 s, while main…

Although it has important ramifications for both the formation of star clusters and their subsequent dynamical evolution, rotation remains a largely unexplored characteristic of young star clusters (few Myr). Using multi-epoch spectroscopic…

Context. Asteroseismic studies showed that cores of post main-sequence stars rotate slower than theoretically predicted by stellar models with purely hydrodynamical transport processes. Recent studies on main sequence stars, particularly…

Context: Several hundred candidate hybrid pulsators of type A-F have been identified from space-based observations. Their large number allows both statistical analyses and detailed investigations of individual stars. This offers the…

The dissertation presents result from study of Pre-main sequence (PMS) stars that are in the earliest stages of stellar evolution. These young stellar objects are still in the process of formation, and the energy they emit is produced only…

A systematic search for gamma Dor and gamma Dor - delta Scuti hybrid pulsators was conducted on the CoRoT LRa01 Exo-archive yielding a total of 418 gamma Dor and 274 hybrid candidates. After an automatic jump correction 194 and 167…

The high accuracy of space data increased the number of the periodicities determined for pulsating variable stars, but the mode identification is still a critical point in the non-asymptotic regime. We use regularities in frequency spacings…