相关论文: Stellar Inclination Angles from Be Star H$\alpha$ …
H$\alpha$ emission is a clear indicator of circumstellar activity in Be stars, historically employed to assess the classical Be star (CBe) population in young open clusters (YOCs). The YOC NGC330 in the Small Magellanic Cloud exhibits a…
Aims: To model broad H-alpha wings observed in symbiotic binaries by an optically thin, bipolar stellar wind from their hot components as an alternative to that considering the Raman scattering of Ly-beta photons on atomic hydrogen.…
Context: Stellar flares have an impact on habitable planets. To relate the observations of the Sun with those of stars, one needs to use a Sun-as-a-star analysis, that is, to degrade the resolution of the Sun to a single point. With the…
Many nearby main-sequence stars have been searched for debris using the far-infrared Herschel satellite, within the DEBRIS, DUNES and Guaranteed-Time Key Projects. We discuss here 11 stars of spectral types A to M where the stellar…
Optical long baseline interferometry was recently established as a technique capable of resolving stars and their circumstellar environments at the milliarcsecond (mas) resolution level. This high-resolution opens an entire new window to…
We introduce a method of measuring a lower limit to the amplitude of surface differential rotation from high-precision, evenly sampled photometric time series. It is applied to main-sequence late-type stars whose optical flux modulation is…
We find, from our study of binary spiral galaxies in the Sloan Digital Sky Survey Data Release 6, that the relative orientation of disks in binary spiral galaxies is consistent with their being drawn from a random distribution of…
Using the adaptive optics facilities at the 200-in Hale and 10-m Keck II, we observed in the near infrared a sample of 12 binary and multiple stars and one open cluster. We used the near diffraction limited images of these systems to…
Measuring the distances to Galactic planetary nebulae (PNe) has been an intractable problem for many decades. We have now established a robust optical statistical distance indicator, the H$\alpha$ surface brightness- radius or S-r relation,…
We analyzed ionized gas motion and disk orientation parameters for 15 spiral galaxies. Their velocity fields were measured with the H-alpha emission line by using the Fabry-Perot interferometer at the 6m telescope of SAO RAS. Special…
Kjeldsen et al. (1995, AJ 109, 1313; astro-ph/9411016) have developed a new technique for measuring stellar oscillations and claimed a detection in the G subgiant eta Boo. The technique involves monitoring temperature fluctuations in a star…
Recently, the first successful attempt at computing stellar models in two dimensions has been presented with models that include the centrifugal deformation and self-consistently compute the velocity field. This paper aims at studying the…
Determining the physical properties of microlensing events depends on having accurate angular sizes of the source star. Using long-baseline optical interferometry we are able to measure the angular sizes of nearby stars with uncertainties…
In spite of the almost all-encompassing variability of Be stars, surveys play a steadily increasing role in complementing the insights gained from single-star studies. The definition of classical Be stars as recently augmented by…
The observed fraction of pulsars with interpulses, their period distribution and the observed pulse width versus pulse period correlation is shown to be inconsistent with a model in which the angle alpha between the magnetic axis and the…
We have used laser guide star adaptive optics and a near-infrared dual-channel imaging polarimeter to observe light scattered in the circumstellar environment of Herbig Ae/Be stars on scales of 100-300 AU. We discover a strongly polarized,…
We developed a new selection method of halo stars in the phase-space distribution defined by the three integrals of motion in an axisymmetric Galactic potential, ($E$, $L_z$, $I_3$), where $I_3$ is the third integral of motion. The method…
Omicron Aquarii is late-type, Be shell star with a stable and nearly symmetric H$\alpha$ emission line. We combine H$\alpha$ interferometric observations obtained with the Navy Precision Optical Interferometer (NPOI) covering 2007 through…
The origin of the disks around Be stars is still not known. Further progress requires a proper parametrization of their structure, both spatially and kinematically. This is challenging as the disks are very small. Here we assess whether a…
We analyse the current build-up of stellar mass within the disks and bulges of nearby galaxies through a comparison of the spatial distributions of forming and old stellar populations. H alpha and R-band imaging are used to determine the…