相关论文: GR 290 (Romano's Star): 2. Light history and evolu…

The high-frequency peaked BL Lac object 1ES 0229+200 (z = 0.14) was first detected in very high energy (VHE, E > 100 GeV) $\gamma$-rays by the H.E.S.S. (High Energy Stereoscopic System) collaboration in 2006. No flux variability was…

We report on a spectroscopic determination of the stellar parameters and chemical abundances for the parent star of the transiting planet TrES-1. Based on a detailed analysis of iron lines in our Keck and HET spectra we derive…

The more massive counterparts of T Tauri stars, Herbig Ae/Be stars, are known to vary in a complex way with no variability mechanism clearly identified. We attempt to characterize the optical variability of HD~37806 (MWC 120) on time scales…

We have obtained the most extensive and most accurate photometric data of a Blazhko variable MW Lyr during the 2006-2007 observing seasons. The data within each 0.05 phase bin of the modulation period (P_m=1/f_m) cover the entire light…

Long slit spectra of the region around the Luminous Blue Variable AG Car obtained in June 1990, just before the onset of its new brightening phase, indicate that AG Car was in the hottest phase so far recorded. The spectrum shows strong…

Sunspots depict large variability during the last 100 years, a period called the Modern Maximum (MM). However, other variables are needed to study the long-term evolution, e.g., of weaker fields and different radiative emissions. Recently,…

The progenitors of Type IIP supernovae have an apparent upper limit to their initial masses of about 20 solar masses, suggesting that the most massive red supergiants evolve to warmer temperatures before their terminal explosion. But very…

The extreme-ultraviolet (EUV; 100 -- 911 \AA) spectra of F, G, K, and M stars provide diagnostics of the stellar chromosphere through the corona, with line and continuum formation temperatures spanning roughly 10$^{4}$ - 10$^{7}$ K. The EUV…

A sample of 116 Long Period Variables is studied with the aim to reveal relations between the properties of their light curves and of their evolution along the Asymptotic Giant Branch (AGB). Each light curve is carefully scrutinized and its…

GRB 130427A was extremely bright as a result of occurring at low redshift whilst the energetics were more typical of high-redshift gamma-ray bursts (GRBs). We collected well-sampled light curves at 1.4 and 4.8 GHz of GRB 130427A with the…

Twenty-one new optical light curves, including five curves obtained in 2009 and sixteen curves detected from the AAVSO International Database spanning from 1977 to 2011, demonstrate 16 new primary minimum light times in the high state.…

We present the variability study of the lowest-luminosity Seyfert 1 galaxy NGC 4395 based on the photometric monitoring campaigns in 2017 and 2018. Using 22 ground-based and space telescopes, we monitored NGC 4395 with a $\sim$5 minute…

The supernova impostor SN 2010da located in the nearby galaxy NGC 300, later identified as a likely supergiant B[e] high-mass X-ray binary, was simultaneously observed by NuSTAR and XMM-Newton between 2016 December 16 and 20, over a total…

As part of a multi-year survey for Wolf-Rayet stars in the Magellanic Clouds, we have discovered a new type of Wolf-Rayet star with both strong emission and absorption. While one might initially classify these stars as WN3+O3V binaries…

Late-time BVRIJHK photometry of the peculiar Type Ic SN 2002ap, taken between 2002 June 12 and 2003 August 29 with the MAGNUM telescope, is presented. The light curve decline rate is derived in each band and the color evolution is studied…

Results of the time variability monitoring of the two classical T Tauri stars, RU Lup and IM Lup, are presented. Three photometric data sets were utilised: (1) simultaneous (same field) MOST satellite observations over four weeks in each of…

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…

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…

The radio source G1.9+0.3 has recently been identified as the youngest known Galactic supernova remnant, with a putative age of ~100 years. We present a radio light curve for G1.9+0.3 based on 25 epochs of observation with the Molonglo…

The data of photometric measurements of the long-period eclipsing variable epsilon Aur in the two main minima 1982 and 2010 in the spectral range of 1--5 microns are presented. Noted is the similarity of light curves in eclipse, its…