相关论文: Altair's Oblateness and Rotation Velocity

We used the optical and near-infrared imagers located on the Liverpool, the IAC80, and the William Herschel telescopes to monitor 18 M7$-$L9.5 dwarfs with the objective of measuring their rotation periods. We achieved accuracies typically…

Physical processes working in the stellar interiors as well as the evolution of stars depend on some fundamental stellar properties, such as mass, radius, luminosity, and chemical abundances. A classical way to test stellar interior models…

The first UBV(RI)_C time series photometry of the RRd star V372 Ser is presented to determine some parameters of the star. In April, May 2007 2812 U, B, V, R_C, I_C frames were obtained at Konkoly and Teide Observatories, 1508 V…

In a study of Chandra High Energy Transmission Grating spectra of Algol, we clearly detect Doppler shifts caused by the orbital motion of Algol B. These data provide the first definitive proof that the X-ray emission of Algol is dominated…

CONTEXT: The study of pulsation in Pre--Main--Sequence intermediate-mass stars represents an important tool for deriving information on fundamental stellar parameters and internal structure, as well as for testing current theoretical…

Measuring the stellar position angle provides valuable information on binary stellar formation or stellar spin axis evolution. We aim to develop a method for determining the absolute stellar position angle using spectro-astrometric analysis…

We present new astrometric and polarimetric observations of flares from Sgr A* obtained with GRAVITY, the near-infrared interferometer at ESO's Very Large Telescope Interferometer (VLTI), bringing the total sample of well-covered…

We report extensive spectroscopic and differential photometric BVRI observations of the active, detached, 1.309-day double-lined eclipsing binary IM Vir, composed of a G7-type primary and a K7 secondary. With these observations we derive…

Asteroid (7) Iris is an ideal target for disk-resolved imaging owing to its brightness (V$\sim$7-8) and large angular size of 0.33 arcsec during its apparitions. Iris is believed to belong to the category of large unfragmented asteroids…

[abridged] Our knowledge of the inner structure of embedded massive young stellar objects is still quite limited. We attempt here to overcome the spatial resolution limitations of conventional thermal infrared imaging. We employed…

We present new high resolution (R = 21,000) near-infrared (2 microns) spectroscopic observations of a sample of Class I and flat-spectrum protostellar objects in the rho Ophiuchi dark cloud. None of the five Class I spectra show CO v = 0 --…

We measured the mid-infrared extension of the gaseous disk surrounding seven Be stars in order to constrain the geometry of their circumstellar environments and to try to infer physical parameters characterizing these disks. We used the…

Stellar rotation is a key in our understanding of both mass-loss and evolution of intermediate and massive stars. It can lead to anisotropic mass-loss in the form of radiative wind or an excretion disk. We wished to spatially resolve the…

(Abridged) The solar system gas giant planets are oblate due to their rapid rotation. A measurement of the planet's projected oblateness would constrain the planet's rotational period. Planets that are synchronously rotating with their…

Using a new grism at the Keck Interferometer, we obtained spectrally dispersed (R ~ 230) interferometric measurements of the Mira star R Vir. These data show that the measured radius of the emission varies substantially from 2.0-2.4…

We obtained 7 spectra of the Be star V423 Aur on Dec. 5th, 2017 using the LAMOST Medium-Resolution Spectrograph with exposures from 600 to 1200 seconds. These spectra show the irregular H{\alpha} emission line profile variations (LPVs). In…

Context : The properties of the inner disks of bright Herbig AeBe stars have been studied with near infrared (NIR) interferometry and high resolution spectroscopy. The continuum and a few molecular gas species have been studied close to the…

We carried out spectroscopic observations with Subaru/HDS of 50 solar-type superflare stars found from Kepler data. More than half (34 stars) of the target stars show no evidence of the binary system, and we confirmed atmospheric parameters…

We present measurements of the stellar velocity dispersion in the inner 1 arcmin radius (1.3 disk scale-lengths) of the irregular galaxy NGC 4449 determined from long-slit absorption-line spectra. The average observed dispersion is 29 +/-2…

We report the detection of a strong, organized magnetic field in the helium-variable early B-type star HR 7355 using spectropolarimetric data obtained with ESPaDOnS on the 3.6-m Canada-France-Hawaii Telescope within the context of the…