Relation between components of binary stars

Payne-Gaposchkin, Cecilia; Gaposchkin, Sergei

doi:10.1086/105890

Cited by 9 publications

(10 citation statements)

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“…N is the total number of observations used to form the mean values, and σ is the rms error (per observation) in mmag. References are: Hertzsprung (1924) discovered the eclipsing nature of DW Car, and photographic light curves have been published by him, by van den Hoven van Genderen (1941), and by Gaposchkin (1952Gaposchkin ( , 1953, who also noted that the previously published value for the orbital period had to be doubled. Radial velocities and spectroscopic elements, based on 39-86 Å/mm photographic spectra, were published by Ferrer et al (1985).…”

Section: Dw Carmentioning

confidence: 99%

“…type B3 IV, P = 4. d 56) is a southern double-lined eclipsing binary consisting of two stars, which have evolved to the TAMS region (6.6 and 6.8 M ), plus at least one more star. Hertzsprung (1926) discovered its eclipsing nature, and an ephemeris and photographic light curves have been published by Gaposchkin (1952Gaposchkin ( , 1953. We refer to Johansen et al (1997) and Ilijić et al (2004) for more recent information.…”

Section: Ac Velmentioning

confidence: 99%

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Four-colour photometry of eclipsing binaries

Clausen

Helt

Giménez

et al. 2006

A&A

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Aims. In order to increase the limited number of B-stars with accurately known dimensions, and also the number of well studied eclipsing binaries in open clusters, we have undertaken observations and studies of four southern double-lined eclipsing B-type binaries; DW Car, BF Cen, AC Vel, and NSV 5783. Methods. Complete uvby light curves were observed between January 1982 and April 1991 at the Danish 0.5 m telescope at ESO La Silla, since 1985 known as the Strömgren Automatic Telescope (SAT). Standard indices for the systems and the comparison stars, as well as additional minima observations for AC Vel, have been obtained later at SAT. For DW Car and AC Vel, high-resolution spectra for definitive spectroscopic orbits have also been obtained; they are presented as part of the detailed analyses of these systems. A few spectra of NSV 5783 are included in the present paper. Results. For all four systems, the first modern accurate light curves have been established. DW Car is a detached system consisting of two nearly identical components. It is member of the young open cluster Cr228. A detailed analysis, based on the new light curves and 29 high-resolution spectra, is published separately. BF Cen is semidetached and is member of NGC 3766. Modern spectra are needed for a detailed study. AC Vel is a detached system with at least one more star. A full analysis, based on the new light curves and 18 high-resolution spectra, is published separately. NSV 5783 is discovered to be an eclipsing binary consisting of two well-detached components in an 11-day period eccentric (e = 0.18) orbit. Secondary eclipse is practically total. From the light curves and a few high-resolution spectra, accurate photometric elements and preliminary absolute dimensions have been determined. The quite similar components have masses of about 5 M and radii of about 3.5 R , and they seem to have evolved just slightly off the ZAMS. The measured rotational velocities (≈150 km s −1 ) are about 6 times those corresponding to pseudosynchronization.

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Section: Dw Carmentioning

confidence: 99%

Section: Ac Velmentioning

confidence: 99%

Four-colour photometry of eclipsing binaries

Clausen

Helt

Giménez

et al. 2006

A&A

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“…The light curve during 1945-1947 is from photographic and visual observations (bottom panel, filled circles) listed in Gaposchkin (1949). The light curve before the brightness decrease of 1945 August is obtained from Payne- Gaposchkin & Mayall (1946;bottom panel, open symbols). The open circles are 20 day means with five or more photographic estimates, while the open squares show two to four estimates.…”

Section: Is Cas Bouncing Against the Yellowmentioning

confidence: 99%

High‐Resolution Spectroscopy of the Yellow Hypergiant ρ Cassiopeiae from 1993 through the Outburst of 2000–2001

Lobel

Dupree

Stefanik

et al. 2003

ApJ

151

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We present an overview of the spectral variability of the peculiar F-type hypergiant Cas, obtained from our long-term monitoring campaigns over the past 8.5 yr with four spectrographs in the northern hemisphere. Between 2000 June and September an exceptional variability phase occurred when the V brightness dimmed by about a full magnitude. The star recovered from this deep minimum by 2001 April. It is the third outburst of Cas on record in the last century. We observe TiO absorption bands in high-resolution near-IR spectra obtained with the Utrecht Echelle Spectrograph during the summer of 2000. TiO formation in the outer atmosphere occurred before the deep brightness minimum. Atmospheric models reveal that the effective temperature decreases by at least 3000 K, and the TiO shell is driven supersonically with _ M M ' 5:4 Â 10 À2 M yr À1 . Strong episodic mass loss and TiO have also been observed during the outbursts of 1945-1947 and 1985-1986. A detailed analysis of the exceptional outburst spectra is provided, by comparing with high-resolution optical spectra of the early M-type supergiants l Cep (Ia) and Betelgeuse (Iab). During the outburst, central emission appears above the local continuum level in the split Na D lines. A prominent optical emission line spectrum appears in variability phases of fast wind expansion. The radial velocity curves of H and of photospheric metal absorption lines signal a very extended and velocity-stratified dynamic atmosphere. The outburst spectra indicate the formation of a low-temperature, optically thick circumstellar gas shell of 3 Â 10 À2 M during 200 days, caused by dynamic instability of the upper atmosphere of this pulsating massive supergiant near the Eddington luminosity limit. We observe that the mass-loss rate during the outburst is of the same order of magnitude as has been proposed for the outbursts of Carinae. We present calculations that correctly predict the outburst timescale, whereby the shell ejection is driven by the release of hydrogen ionization recombination energy.

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“…The Fourier analyses of RVs do not show any clear short period compatible with that derived by Lamontagne et al (1982). Photometric studies have also been conducted by Martin & Plummer (1919), Gaposchkin (1946), andRoss (1961), who first reported on the low-level irregular variability of WR 138, and a photometric period of 11.6 d was reported by . However, these results are based on limited and sparse time-series that are not adequate for distinguishing between periodic and sporadic variations such as are frequently found in photometric observations of WR stars (e.g.…”

Section: Discussionmentioning

confidence: 62%

WR 138: new results from X-ray and optical spectroscopy

Palate

Rauw

Becker

et al. 2013

A&A

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Context. Massive-binary evolution models predict that some systems will go through an evolutionary phase where the original primary has become a supernova and left a compact object behind that then orbits a Wolf-Rayet (WR) star. WR 138 is an X-ray bright WR star that has been described as a triple system, including a compact companion in a short-period orbit. Aims. Our goal is to search for spectroscopic evidence of a compact companion around WR 138. Methods. We used optical and X-ray spectra to search for signatures of a compact companion, which can be revealed by systematic variations in WR optical spectral lines induced by orbital motion of the compact companion or by hard, luminous X-rays from accretion onto this companion. Results. The optical spectra display emission-line profile variations that are most probably caused by clumps inside the stellar winds. The radial velocities do not vary on a short time-scale compatible with the suggested orbital period of a putative compact companion. The X-ray spectra are found to be normal for a WN5-6+OB system with no indication of accretion by a compact companion. Conclusions. There is no evidence for the presence of a compact companion, and we therefore conclude that WR 138 is a normal long-period (P ∼ 1521 d) eccentric WR+OB system.

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Relation between components of binary stars

Cited by 9 publications

References 0 publications

Four-colour photometry of eclipsing binaries

Four-colour photometry of eclipsing binaries

High‐Resolution Spectroscopy of the Yellow Hypergiant ρ Cassiopeiae from 1993 through the Outburst of 2000–2001

WR 138: new results from X-ray and optical spectroscopy

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