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Kippenhahn, Rudolf; Weigert, Alfred

doi:10.1007/978-3-642-61523-8_17

Cited by 33 publications

(50 citation statements)

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“…The simplest explanation is that the position of the secondary in the Hertzsprung–Russell (HR) diagram is just that of a normal star crossing the Hertzsprung gap. Because such a star no longer burns hydrogen in the core, this is a massive Case B mass transfer as defined by Kippenhahn & Weigert (1967, hereafter KW). Provided that the initial mass ratio q i ≲1 the binary always expands on mass transfer, which occurs on a thermal time‐scale.…”

Section: Models For Cygnus X‐2mentioning

confidence: 99%

Cygnus X-2, super-Eddington mass transfer, and pulsar binaries

King

Ritter

1999

Monthly Notices of the Royal Astronomical Society

104

123

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We consider the unusual evolutionary state of the secondary star in Cygnus X-2. Spectroscopic data give a low mass ($M_2 \simeq 0.5 - 0.7\msun$) and yet a large radius ($R_2 \simeq 7\rsun$) and high luminosity ($L_2 \simeq 150\lsun$). We show that this star closely resembles a remnant of early massive Case B evolution, during which the neutron star ejected most of the $\sim 3\msun$ transferred from the donor (initial mass $M_{\rm 2i}\sim 3.6\msun$) on its thermal time-scale $\sim 10^6$ yr. As the system is far too wide to result from common-envelope evolution, this strongly supports the idea that a neutron star efficiently ejects the excess inflow during super--Eddington mass transfer. Cygnus X-2 is unusual in having had an initial mass ratio $q_{\rm i} = M_{\rm 2i}/M_1$ in a narrow critical range near $q_{\rm i}\simeq 2.6$. Smaller $q_{\rm i}$ lead to long-period systems with the former donor near the Hayashi line, and larger $q_{\rm i}$ to pulsar binaries with shorter periods and relatively massive white dwarf companions. The latter naturally explain the surprisingly large companion masses in several millisecond pulsar binaries. Systems like Cygnus X-2 may thus be an important channel for forming pulsar binaries.Comment: 9 pages, 4 encapsulated figures, LaTeX, revised version with a few typos corrected and an appendix added, accepted by MNRA

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Section: Models For Cygnus X‐2mentioning

confidence: 99%

Cygnus X-2, super-Eddington mass transfer, and pulsar binaries

King

Ritter

1999

Monthly Notices of the Royal Astronomical Society

104

123

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“…Here we shall treat the problem of handling the integration of outer layers adequately for the case in which there is mass transfer; if not, then outer layers are managed as in Kippenhahn et al (1967a). We refer the reader to that paper for further details in this simple situation and only describe here its modifications to account for the occurrence of mass transfer.…”

Section: Handling Outer‐layer Integrationmentioning

confidence: 99%

“…If not, we change the values of and . Also, if (log L /L ⊙ , log T eff ), were outside the assumed HR triangle we change it with the algorithm presented in Kippenhahn et al (1967a) but now with the same mass and MTR values.…”

Section: Handling Outer‐layer Integrationmentioning

confidence: 99%

“…In view of the large number of situations that can be encountered, it is not surprising that CBSs are considered as favourable places for the occurrence of a number of phenomenologies of high astrophysical interest: X‐ray sources (van der Klis 2000), low‐mass helium white dwarfs (Kippenhahn, Kohl & Weigert 1967a), planetary nebulae with binary nucleus (Iben & Livio 1993), binary radio pulsars (Bhattacharya & van den Heuvel 1991) and supernova progenitors (Podsiadlowski, Joss & Hsu 1992). In this last case, binary evolution naturally accounts for the evolution of the progenitor of SN 1987A.…”

Section: Introductionmentioning

confidence: 99%

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A code for stellar binary evolution and its application to the formation of helium white dwarfs

Benvenuto

Vito

2003

Monthly Notices of the Royal Astronomical Society

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We present a numerical code intended for calculating stellar evolution in close binary systems. In doing so, we consider that mass transfer episodes occur when the stellar size overflows the corresponding Roche lobe. In such a situation we equate the radius of the star to the equivalent radius of the Roche lobe. This equation is handled implicitly together with those corresponding to the whole structure of the star. We describe in detail the necessary modifications to the standard Henyey technique for treating the mass-loss rate implicitly together with thin outerlayer integrations.We have applied this code to the calculation of the formation of low-mass, helium white dwarfs in low-mass close binary systems. We find that the global numerical convergence properties are fairly good. In particular, the onset and end of mass transfer episodes are computed automatically.

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“…If the donor star is more massive than the accreting white dwarf, the mass transfer will tend to be unstable. As long as the donor star is not sufficiently evolved, the mass transfer will be unstable on a thermal, rather than a dynamical timescale (Paczynski 1965(Paczynski , 1967Kippenhahn, Kohl & Weigert 1967;Webbink 1979Webbink , 1985Webbink , 1992 use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S007418090005587X…”

Section: Estimating the Underlying Population Of Supersoft Sourcesmentioning

confidence: 99%

Luminous Supersoft X-ray Sources

Rappaport¹,

Stefano

1996

Symp. - Int. Astron. Union

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Supersoft X-ray sources exhibit spectra that are remarkably steep, in that the ratio of low-to-high energy X rays is much larger than is characteristic of the spectra associated with the previously known classes of luminous X-ray sources. The first supersoft sources were discovered during a survey of the Large Magellanic Cloud with the EINSTEIN Observatory (Long et al. 1981). The all-sky X-ray survey carried out with ROSAT has now established that luminous supersoft X-ray sources constitute a distinct astronomical class (see, e.g., Hasinger 1994). A number of the identified optical counterparts of the supersoft X-ray sources exhibit blue continua with emission lines of H and He II (Smale et al. 1988; Pakull et al. 1988; Cowley et al. 1990), which are characteristic of accretion disks. The X-ray emission of some sources is steady, while others exhibit significant time variability. Table 1 briefly summarizes what is known thus far about the numbers and characteristics of supersoft X-ray sources (see Hasinger 1994, and references therein).

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Cited by 33 publications

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Cygnus X-2, super-Eddington mass transfer, and pulsar binaries

Cygnus X-2, super-Eddington mass transfer, and pulsar binaries

A code for stellar binary evolution and its application to the formation of helium white dwarfs

Luminous Supersoft X-ray Sources

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