相关论文: The Wind of Variable C in M33

The paradigmatic Luminous Blue Variable R127 in the Large Magellanic Cloud has been found in the intermediate, peculiar early-B state, and substantially fainter in visual light, signaling the final decline from its major outburst that began…

We present the results of the analysis of the SRG/ART-XC observation of the Supergiant Fast X-ray Transient IGR J16195-4545 performed on March 3, 2021. Six bright flares are present in the light curve, with no significant change in hardness…

CONTEXT: The RAVE spectroscopic survey for galactic structure and evolution obtains 8400-8800 Ang spectra at 7500 resolving power at the UK Schmidt Telescope using the 6dF multi-fiber positioner. More than 300,000 9<I<12 and |b|>25 deg…

Using Keck/HIRES spectra {\Delta}v ~ 7 km/s, we analyze forbidden lines of [O I] 6300 {\AA}, [O I] 5577 {\AA} and [S II] 6731 {\AA} from 33 T Tauri stars covering a range of disk evolutionary stages. After removing a high velocity component…

The massive post-Main Sequence star W243 in the galactic starburst cluster Westerlund 1 has undergone a spectral transformation from a B2Ia supergiant devoid of emission features in 1981 to an A-type supergiant with a rich emission-line…

The slow, dense winds observed in evolved asymptotic giant branch (AGB) stars are usually attributed to a combination of dust formation in the dynamical inner atmosphere and momentum transfer from stellar photons interacting with the newly…

In this work, we present the results of our multi-band microvariability study of the famous blazar BL Lac. We performed microvariablity observations of the source in the optical VRI bands for 4 nights in the year 2016. We studied the…

We present the results of a detailed spectroscopic analysis of 20 years of observations of AG Carinae using the radiative transfer code CMFGEN. Among the conclusions of this work, we highlight the importance of including time-dependent…

Densely time sampled multi-frequency flux measurements of the extreme BL Lac object S5 0716+714 over the past three years allow us to study its broad-band variability, and the detailed underlying physics, with emphasis on the location and…

We review the various techniques through which wind properties of massive stars - O stars, AB supergiants, Luminous Blue Variables (LBVs), Wolf-Rayet (WR) stars and cool supergiants - are derived. The wind momentum-luminosity relation (e.g.…

The Balmer lines of four A Ia - supergiants (spectral type A0 to A3) and fourteen B Ia and Ib - supergiants (spectral type B0 to B3) in the solar neighbourhood are analyzed by means of NLTE unified model atmospheres to determine the…

Stellar winds of massive stars are known to be driven by line absorption of UV photons, a mechanism which is prone to instabilities, causing the wind to be clumpy. The clumpy structure hampers wind mass-loss estimates, limiting our…

The transition from early Of stars to WN type objects is poorly understood. O-type supergiants with emission lines (OIf+) are considered to be intermediate between these two classes. The scope of this paper is to investigate the spectral…

We present an update of 3C 273's database hosted by the ISDC, completed with data from radio to gamma-ray observations over the last 10 years. We use this large data set to study the multiwavelength properties of this quasar,especially…

Model parametrizations in the convective boundary layer are still at work especially in the interfacial layers with the surface and the free troposphere. The present paper reports simultaneous turbulence-scale lidar observations of wind…

We report optical observations of the Luminous Blue Variable (LBV) HR Carinae which show that the star has reached a visual minimum phase in 2009. More importantly, we detected absorptions due to Si IV 4088-4116 Angstroms. To match their…

B supergiants (BSGs) are evolved stars with effective temperatures between 10 to 30 kK and are important to understand massive star evolution. Located on the edge of the line-driven wind regime, the study of their atmospheres is helpful to…

The density fluctuation spectrum in the solar wind reveals a Kolmogorov-like scaling with a spectral slope of -5/3 in wavenumber space. The energy transfer process in the magnetized solar wind, characterized typically by MHD turbulence,…

We constrain wind parameters of a sample of 18 O-type stars in the LMC, through analysis with stellar atmosphere and wind models including the effects of optically thick clumping. This allows us to determine the most accurate spectroscopic…

We present photometry and spectroscopy of the suspected cataclysmic variable (CV) Lanning 386. We confirm that it is a CV, and observe deep eclipses, from which we determine the orbital period Porb to be 0.1640517 +- 0.0000001 d (= 3.94 h).…