منابع مشابه
Analysis of the irregular pulsations of AC Herculis
The AAVSO lightcurve data of the irregularly pulsating star AC Herculis of the RV Tau class are analysed. The lightcurve is shown not to be compatible with a periodic, or even multiperiodic pulsation, even if allowance ismade for evolution. Instead the best explanation is that the irregularly alternating cycles are a manifestation of low dimensional chaos. Our flow reconstruction suggests that ...
متن کاملLecture XXI: Radial pulsations and stability
Having constructed the equilibrium stellar configurations, we are now poised to ask whether they are stable to small perturbations. This leads us to the subject of relativistic stellar pulsations. One may classify such pulsations by their angular dependence: when we investigate the full subject we will find modes of every spherical harmonic index l ≥ 0. However, for the cold stars of interest t...
متن کاملRadial pulsations and stability of protoneutron stars
Radial pulsations of newborn neutron stars (protoneutron stars) are studied for a range of internal temperatures and entropies per baryon predicted by the existing numerical simulations. Protoneutron star models are constructed using a realistic equation of state of hot dense matter, and under various assumptions concerning stellar interior (large trapped lepton number, zero trapped lepton numb...
متن کاملAurigae: strong evidence for non-radial pulsations
We present further photometric observations of the unusual F0 V star 9 Aurigae and present evidence that this star’s radial velocity, spectroscopic line widths and line depths are also variable with the same frequencies as the photometric data (f1 ≈ 0.795 and f2 ≈ 0.345 d ). The phases of these sinusoids are stable over time scales of longer than one year, though the amplitudes can vary, making...
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: 1993
ISSN: 0252-9211
DOI: 10.1017/s0252921100018753