Pulsational instability of yellow hypergiants

@article{Fadeyev2011PulsationalIO,
  title={Pulsational instability of yellow hypergiants},
  author={Yu. A. Fadeyev},
  journal={Astronomy Letters},
  year={2011},
  volume={37},
  pages={403-413}
}
Instability of population I (X = 0.7, Z = 0.02) massive stars against radial oscillations during the post-main-sequence gravitational contraction of the helium core is investigated. Initial stellar masses are in the range 65M⊙ ≤ MZAMS ≤ 90M⊙. In hydrodynamic computations of self-exciting stellar oscillations we assumed that energy transfer in the envelope of the pulsating star is due to radiative heat conduction and convection. The convective heat transfer was treated in the framework of the… Expand

Figures from this paper

Instability of the kinematic state in the atmosphere of the hypergiant ρ Cas outside outburst
Multiple observations of the yellow hypergiant ρ Cas obtained in 2007–2011 in a wide wavelength range with spectroscopic resolving power R ≥ 60 000 have enabled studies of features of its opticalExpand
Changes of the Optical Spectrum of the Hypergiant ρ Cas due to a Shell Ejection in 2013
Spectral monitoring of the yellow hypergiant ρ Cas with the by 6-m telescope of the Special Astrophysical Observatory with a spectral resolution of R ≥ 60 000 has led to the detection of new featuresExpand
Pulsations, eruptions, and evolution of four yellow hypergiants
Aims. We aim to explore the variable photometric and stellar properties of four yellow hypergiants (YHGs), HR 8752, HR 5171A, ρ Cas, and HD 179821, and their pulsations of hundreds of days, andExpand
How much radioactive nickel does ASASSN-15lh require?
The discovery of the most luminous supernova ASASSN-15lh triggered a shock-wave in the supernova community. The three possible mechanisms proposed for the majority of other superluminous supernovaeExpand
Investigating the nature of the Fried Egg nebula CO mm-line and optical spectroscopy of IRAS 17163-3907
Through CO mm-line and optical spectroscopy, we investigate the properties of the Fried Egg nebula IRAS 17163–3907, which has recently been proposed to be one of the rare members of the yellowExpand
Multicolor Photometry and Spectroscopy of the Yellow Supergiant with Dust Envelope HD 179821 = V1427 Aquilae
We present the results of multicolor (UBV JHKLM) photometry (2009–2017) and low-resolution spectroscopy (2016–2017) of the semi-regular variable V1427 Aql = HD 179821, a yellow supergiant withExpand

References

SHOWING 1-10 OF 23 REFERENCES
Radial pulsations of massive main-sequence stars
The evolution of Population I stars (X = 0.7, Z = 0.02) with initial masses 40M⊙ ≤ MZAMS ≤ 120M⊙ until core hydrogen exhaustion has been computed. Models of evolutionary sequences have been used asExpand
Instability of radial modes at the Wolf-Rayet evolutionary stage
AbstractThe evolution of a Population-I star with an initial mass MZAMS = 60 M⊙ has been calculated. At the stage when a red giant turns into an early-type helium star, the vast bulk of the stellarExpand
Instability of LBV stars against radial oscillations
Hydrodynamic calculations of nonlinear radial oscillations of LBV stars with effective temperatures 1.5 × 104 K ⩽ Teff ⩽ 3 × 104 K and luminosities 1.2 × 106L⊙ ⩽ L ⩽ 1.9 × 106L⊙ have been performed.Expand
Turbulent Pressure in the Envelopes of Yellow Hypergiants and Luminous Blue Variables
The manner in which turbulence (especially turbulent pressure) affects the structure and stability of luminous post-red-supergiant stars is critically evaluated by calculating both realistic andExpand
Non-linear pulsation models of red giants
There are currently unresolved differences between fundamental mode red giant pulsation models and the large amplitude pulsation behaviour of real stars. In particular, current models tend to beExpand
The yellow hypergiants
We list the main stellar data of known hypergiants and similarly luminous stars, and then concentrate on a review of the yellow hypergiants. These stars are post-red supergiants evolving alongExpand
An obstacle to the late evolution of massive stars
During their evolution, massive stars first swell and thus become red supergiants, after which they shrink again to evolve to the blue supergiant phase. When, during this blueward loop, the effectiveExpand
Instability regions in the upper HR diagram
The following instability regions for blueward evolving-supergiants are outlined and compared. (1) Areas in the Hertzsprung–Russell (HR) diagram where stars are dynamically unstable. (2) Areas whereExpand
Convective hydrocodes for radial stellar pulsation. Physical and numerical formulation
In this paper we describe our convective hydrocodes for radial stellar pulsation. We adopt the Kuhfuss (1986) model of convection, reformulated for the use in stellar pulsation hydrocodes. PhysicalExpand
On the CO Near-Infrared Band and the Line-splitting Phenomenon in the Yellow Hypergiant ρ Cassiopeiae
We report on multiepoch optical and near-infrared spectroscopy around the first-overtone rovibrational band of CO in the pulsating yellow hypergiant ρ Cas, one of the most massive stars in the GalaxyExpand
...
1
2
3
...