Evolutionary sequence: Red giant-planetary nebula-white dwarf

Astrophysics ◽  
1975 ◽  
Vol 9 (3) ◽  
pp. 246-248
Author(s):  
O. Kh. Guseinov
Keyword(s):  
White Dwarf ◽  
Planetary Nebula ◽  
Evolutionary Sequence ◽  
Red Giant

scholarly journals Production of Planetary Nebulae

1968 ◽  
Vol 34 ◽  
pp. 400-406
Author(s):  
M.P. Savedoff ◽  
G.S. Kutter ◽  
H.M. Van Horn
Keyword(s):  
Effective Temperature ◽  
White Dwarf ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Evolutionary Sequence ◽  
Solar Mass ◽  
Peak Luminosity

For various reasons, we have been studying evolution in the pre-white dwarf phase at Rochester. Our attention to the relevance of this work to planetary nebulae came as a result of calculations of the evolution of a one solar-mass iron star carried out at Rochester by S. Vila. Here the neutrino processes drive the peak luminosity to log L/L⊙=4·26, at an effective temperature log Teff=5·53. Although these models are brighter than 100 L⊙ for 500 000 years, they are brighter than 1000 L⊙ for 4000 years, and exceed 10000 L⊙ for 900 years. We are therefore near the luminosity of the planetary-nebula nuclei, but considerably hotter, for a period of the order of the planetary lifetimes. Except for the temperature discrepancy, these models are in rough agreement with the observationally determined evolutionary sequence found by O'Dell (1963) and by Harman and Seaton (1964) and Seaton (1966).

scholarly journals Planetary Nebula Formation

1992 ◽  
Vol 9 ◽  
pp. 631-633
Author(s):  
Sun Kwok
Keyword(s):  
Interstellar Medium ◽  
White Dwarf ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Exact Nature ◽  
Common Phenomenon ◽  
The Galaxy ◽  
Stellar Temperature ◽  
Red Giant ◽  
Short Time

The idea that planetary nebulae (PN) originate from the outer atmospheres of red giant was first proposed by Shkloskii (1956). In the early 1970’s, it was generally believed that PN were created by a sudden envelope ejection; however, the exact nature of the instability responsible for the ejection was not understood. Furthermore, it was not clear how the observed masses of PN are related to the amount of mass ejected, and there was no explanation of how the observed shell morphologies of PN could be created by such instabilities. From the observed sizes and expansion velocities of PN, we know that the dynamical lifetime of a PN is ~104yr. During this period, the star has to evolve from the red side of the H-R diagram, where the envelope is ejected, to the blue side of the H-R diagram, where the stellar temperature is high enough to photoionize the ejecta. If the star evolves too slowly, the nebula will have dispersed into the interstellar medium before it is ionized. If the star evolves too fast, then the nebula will only be illuminated for a short time before the stellar luminosity drops on the white dwarf cooling track (Renzini 1982). It is therefore surprising that PN is such a common phenomenon, with ~30000 PN estimated to be in the Galaxy now.

A radio jet associated with the symbiotic star CH Cygni

1986 ◽  
Vol 64 (4) ◽  
pp. 520-522 ◽  
Author(s):  
E. R. Seaquist ◽  
A. R. Taylor
Keyword(s):  
Electron Density ◽  
White Dwarf ◽  
Transverse Velocity ◽  
Stellar Object ◽  
Symbiotic Star ◽  
Ionized Gas ◽  
Radio Outburst ◽  
Supercritical Accretion ◽  
End To End ◽  
Red Giant

We present observations that show that the symbiotic star CH Cygni recently underwent a strong radio outburst that produced a radio-emitting thermal jet. The jet is two-sided and is expanding lengthwise at an observed rate (end to end) of 1 arcsec/year, corresponding to a transverse velocity of 1100 km∙s−1 in each direction. The electron density on January 22, 1985 exceeded 2 × 106 cm−3, and the mass of the (ionized) gas exceeded [Formula: see text]. The emergence of the jet coincided with a decline in the visual luminosity of [Formula: see text].The data are consistent with a jet produced by supercritical accretion in a binary containing a red giant and a [Formula: see text] white dwarf. The discovery of a jet in such a system provides confirming evidence of the role played by accretion in determining the optical and radio properties of this system. It is also the first expanding jet found to be associated with an evolved stellar object.

scholarly journals Helium Shell-Flashes in Accreting White Dwarfs

1979 ◽  
Vol 53 ◽  
pp. 285-289 ◽  
Author(s):  
M. Y. Fujimoto ◽  
D. Sugimoto
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Giant Stars ◽  
Deep Interior ◽  
Constant Rate ◽  
Red Giant Stars ◽  
Red Giant

When gas is accreted onto a carbon-oxygen white dwarf, a hydrogen shell-flash is triggered. Recently such phenomena are studied by many authors in relation to nova explosions and rekindling of white dwarfs. Unless all of the accreted gas is ejected by the process of the nova, a helium zone is formed as a result of hydrogen shell-burning. As the hydrogen shell-flashes recur many times, the helium zone grows gradually in mass. Then the helium shell-flash will be ignited as in the deep interior of ordinary red giant stars. We have investigated such process, simulating it by helium accretion at a constant rate. In the present paper we show that the helium shell-flashes result in a variety of strengths depending upon situations.

scholarly journals Nova GK Persei – A Miniature Supernova Remnant?

1988 ◽  
Vol 101 ◽  
pp. 47-50
Author(s):  
E.R. Seaquist ◽  
D.A. Frail ◽  
M.F. Bode ◽  
J.A. Roberts ◽  
D.C.B. Whittet ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Synchrotron Radiation ◽  
Strong Evidence ◽  
White Dwarf ◽  
Planetary Nebula ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Optical Images ◽  
Ambient Gas ◽  
The Magnetic Field

AbstractWe present radio and optical images of the shell-like remnant of the 1901 outburst of Nova GK Persei. The behaviour of this object is remarkably similar to supernova remnants. The synchrotron radiation-emitting shell is polarized with the magnetic field oriented radially, as in young SNR’s. This similarity plus extensive data we have acquired on the expansion and the interstellar environment of GK Per indicate that the nova shell is colliding with ambient gas whose density is substantially higher than the ISM.Furthermore, there is strong evidence that the ambient gas is circumstellar rather than interstellar, and that this material is the shell of an ancient planetary nebula associated with the white dwarf companion of GK Per.

scholarly journals Symbiotic Stars as Possible Progenitors of SNe Ia: Binary Parameters and Overall Outlook

2011 ◽  
Vol 7 (S281) ◽  
pp. 162-165 ◽  
Author(s):  
J. Mikołajewska
Keyword(s):  
White Dwarf ◽  
Physical Characteristics ◽  
Type Ia Supernovae ◽  
Symbiotic Stars ◽  
Type Ia ◽  
Red Giant ◽  
Ia Supernovae

AbstractSymbiotic stars are interacting binaries in which the first-formed white dwarf accretes and burns material from a red giant companion. This paper aims at presenting physical characteristics of these objects and discussing their possible link with progenitors of Type Ia supernovae.

Supernova: The Result of the Death Spiral of a White Dwarf into a Red Giant

1974 ◽  
Vol 188 ◽  
pp. 149 ◽  
Author(s):  
W. M. Sparks ◽  
T. P. Stecher
Keyword(s):  
White Dwarf ◽  
Death Spiral ◽  
Red Giant
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