منابع مشابه
Periodic radial velocity variations in RU Lupi ⋆
Context. RU Lup is a Classical T Tauri star with unusually strong emission lines, which has been interpreted as manifestations of accretion. Recently, evidence has accumulated that this star might have a variable radial velocity. Aims. We intended to investigate in more detail the possible variability in radial velocity using a set of 68 high-resolution spectra taken at the VLT (UVES), the AAT ...
متن کاملExpansion Parallax of the Planetary Nebula Ic 418
In this paper, we present radio continuum observations of the planetary nebula IC 418 obtained at two epochs separated by more than 20 years. These data allow us to show that the angular expansion rate of the ionization front in IC 418 is 5.8 ± 1.5 mas yr−1. If the expansion velocity of the ionization front is equal to the expansion velocity of the gas along the line of sight as measured by opt...
متن کاملPhotometric observations of the nucleus of IC 418
We discuss the observational characteristics of a recently proposed class of variable central stars of planetary nebulae. We summarize previous observations of the nucleus of IC 418, a prototype star of this class, and we analyze new photometry of this object, obtained in 1989 and 1991. We confirm that the characteristic timescale of the photometric variations is a fewhours.No single period can...
متن کاملAn investigation into the radial velocity variations of CoRoT-7*
Context. CoRoT-7b, the first transiting “superearth” exoplanet, has a radius of 1.7 R⊕ and a mass of 4.8 M⊕. The HARPS radial velocity (RV) measurements used for deriving this mass also detected an additional companion with a period of 3.7 days and a mass of 8.4 M⊕. The mass of CoRoT-7b is a crucial parameter for planet structure models, but is difficult to determine because CoRoT-7 is a modest...
متن کاملRadial Velocity Variations in K Giants: Planets or Pulsations?
Radial velocity observations of K giants have revealed periodic variations for some of the stars. The periods range from approximately 180 to 1000 or more days with velocity amplitudes ranging from approximately 50 m/s to 500 m/s. Except for Iota Draconis (Frink et al. 2002), all variations are nearly sinusoidal. Companions with zero orbital eccentricity as well as pulsations may cause these ra...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1981
ISSN: 0252-9211
DOI: 10.1017/s0252921100094653