Related papers: Eta Carinae long-term variability

We present follow-up optical imaging and spectroscopy of one of the light echoes of $\eta$ Carinae's 19th-century Great Eruption discovered by Rest et al. (2012). By obtaining images and spectra at the same light echo position between 2011…

We study the usage of the X-ray light curve, column density toward the hard X-ray source, and emission measure (density square times volume), of the massive binary system Eta Carinae to determine the orientation of its semi-major axis. The…

We focus on two Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) spectra of the Weigelt Blobs B&D, extending from 1640 to 10400A; one recorded during the 1998 minimum (March 1998) and the other recorded in February…

Well-sampled optical and radio light curves of BL Lacertae in B, V, R, I bands and 4.8, 8.0, 14.5 GHz from 1968 to 2014 were presented in this paper. A possible $1.26 \pm 0.05$ yr period in optical bands and a $7.50 \pm 0.15$ yr period in…

$\eta$ Car is a massive, eccentric binary with a rich observational history. We obtained the first high-cadence, high-precision light curves with the BRITE-Constellation nanosatellites over 6 months in 2016 and 6 months in 2017. The light…

We present new BV time series data of the Carina dwarf spheroidal galaxy. Current data cover an area of about 0.3 square degrees around the center of the galaxy and allowed us to identify 92 variables. Among them 75 are RR Lyrae stars, 15…

We have conducted a long-term V-band photometric monitoring of M33 on 95 nights during four observing seasons (2000 - 2003). A total number of 6418 lightcurves of bright objects in the range of 14 - 21 mag have been obtained. All…

Str\"omgren uvby-beta photometry is reported for the RR Lyrae stars AE, RS, ST, TV, TW, UU, and XX in Bootes. The physical parameters M/Mo, log (L/Lo), M_V, log T_eff and [Fe/H], have been estimated from the Fourier decomposition of the…

In this paper, historical optical(UBVRI) data and newly observed data from the Yunnan Observatory of China(about100 years) are presented for BL Lacertae. Maximum variations in UBVRI: 5.12, 5.31, 4.73, 2.59, and 2.54 and color indices of U-B…

We present 2D radiative transfer modeling of the Eta Carinae binary system accounting for the presence of a wind-wind collision (WWC) cavity carved in the optically-thick wind of the primary star. By comparing synthetic line profiles with…

Deneb is often considered the prototypical A-type supergiant, and is one of the visually most luminous stars in the Galaxy. A-type supergiants are potential extragalactic distance indicators, but the variability of these stars needs to be…

We observed the massive binary stellar system of Eta Carinae in the 0.3-10 keV energy range with the X-ray Telescope onboard the Swift satellite during the period 15 December 2008 - 11 March 2009, i.e. 1 month before to 2 months after the…

We present the results of an intensive ground-based spectrophotometric monitoring campaign of the Seyfert galaxy NGC~4151 for a period of over two months, with a typical temporal resolution of one day. Light curves for four optical…

Context. Luminous blue variables (LBVs) are rare massive stars with very high luminosity. They are characterized by strong photo-metric and spectroscopic variability related to transient eruptions. The mechanisms at the origin of these…

We study the propagation of the ionizing radiation emitted by the secondary star in Eta Carinae. We find that a large fraction of this radiation is absorbed by the primary stellar wind, mainly after it encounters the secondary wind and…

Previous STIS long-slit observations of Eta Carinae identified numerous absorption features in both the stellar spectrum, and in the adjacent nebular spectra, along our line-of-sight. The absorption features became temporarily stronger when…

The evolved, massive highly eccentric binary system, eta Carinae, underwent a periastron passage in the summer of 2014. We obtained two coordinated X-ray observations with XMM-Newton and NuSTAR during the elevated X-ray flux state and just…

We analyzed the light curves of 165 AGB variables, mostly Miras, in the sky area centered between M16 and M17 (l=16, b=0), using the OGLE GVS database in the I_C band. Comparison with the published light curves, derived about 50 years…

We present a detailed spectroscopic analysis of the luminous blue variable AG Carinae during the last two visual minimum phases of its S-Dor cycle (1985-1990 and 2000-2003). The analysis reveals an overabundance of He, N, and Na, and a…

Luminous blue variable stars (LBVs) are of great interest in massive-star evolution as they experience very high mass-loss episodes within short periods of time. HR Car is a famous member of this class in the Galaxy. It has a large…