منابع مشابه
Multiperiodic light variations of active stars
We studied the long-term light behaviour of ten rapidly-rotating active stars (LQ Hya, V833 Tau, EI Eri, V711 Tau, BY Dra, HU Vir, IL Hya, VY Ari, HK Lac, IM Peg) with Fourier analysis. Using photometric databases of up to 30 years in length, we search for periodic or quasi-periodic long-term variations of the overall light levels. Out of the ten stars studied, nine show cyclic variability and ...
متن کاملRadial Velocity Variations in Pulsating Ap Stars . II . 33 Librae ⋆
We present precise relative radial velocity (RV) measurements for the rapidly oscillating Ap (roAp) star 33 Librae measured from high resolution data spanning the wavelength interval 5000–6200 Å. We find that pulsational radial velocity amplitude determined over a broad wavelength range (≈ 100 Å) depends on the spectral region that is examined and can be as high as 60 m s at 5600 Å and as low a...
متن کاملRapidly oscillating Ap stars versus non-oscillating Ap stars
The positions in the HR diagram and the kinematic characteristics of rapidly oscillating and non-oscillating chemically peculiar stars are obtained using new Hipparcos proper motions and parallaxes, and our own radial velocity measurements. We find that rapidly oscillating stars, as a group, are (−0.47±0.34) mag above the zero-age main sequence (ZAMS), while the non-oscillating stars are (−1.20...
متن کاملLight variations of massive stars ( α Cygni variables ) ?
Multi-colour photometry (Walraven system) of five superand hypergiants in the LMC, viz. R 74, R 78, HD 34664, R 84 and R 116, is searched for variability and periods, and discussed. Apart from R 84, of which the claimed variability in the past must be due to a number of faint field stars at the edge of the apertures, all are variable. R 74 and HD 34664 are weak-active LBVs with superimposed mic...
متن کاملLight variations of massive stars ( α Cyg variables ) ?
Multi-colour photometry of four variable supergiants in the LMC and SMC, viz. R 85, R 110, R 42 and R 45, is searched for periods, studied and discussed. The suspected LBV R 85 is undoubtedly an active LBV, though not as spectacular as R 110. Their microvariations superimposed on the S Dor-activity are analyzed as well as those exhibited by R 42 and R 45. Often, a period search is difficult bec...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1986
ISSN: 0252-9211
DOI: 10.1017/s025292110009148x