Contact and near-contact binary systems - II. RR Cen, EZ Hya, V502 Oph and RS Sct

King, David J.; Hilditch, R. W.

doi:10.1093/mnras/209.3.645

Cited by 25 publications

(21 citation statements)

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“…Spectroscopic observations and radial velocity curves of V502 Oph have been published (Struve & Gratton 1948;Struve & Zebergs 1959;King & Hilditch 1984) and more recently presented by Pych et al (2004). The derived orbital elements based on these older observations are surprisingly close to the values based on the more recent data.…”

Section: Introductionsupporting

confidence: 64%

On the Period Variation of the W UMa-type Contact Binary V502 Ophiuchi

Liu

Yang

2006

Chin. J. Astron. Astrophys.

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The variation in the orbital period of the W UMa type contact binary V502 Oph is analyzed. The orbital period exhibits a wavelike variation with a periodicity of 23.0 years and an amplitude of ∆P = 1.24 × 10 −6 days superimposed on secular decrease of dP/dt = 1.68 × 10 −7 day per year. The long-term decrease may be accompanied by the contraction of the secondary at a rate of 83 m per year and a mass transfer rate from the primary to the secondary of 4.28 × 10 −8 M per year. The short-term oscillation may be explained by the presence of a third component. Orbital elements of the third body and its possible mass are presented.

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Section: Introductionsupporting

confidence: 64%

On the Period Variation of the W UMa-type Contact Binary V502 Ophiuchi

Liu

Yang

2006

Chin. J. Astron. Astrophys.

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“… 62: Rucinski et al (2001), 63: Hrivnak et al (2001), 64: Wolf et al (2000), 65: Goecking & Duerbeck (1993), 66: Gazeas et al (in preparation), 67: Hilditch & King (1986), 68: King & Hilditch (1984), 69: Vinkó, Hegedüs & Hendry (1996), 70: Leung & Schneider (1978), 71: Maciejewski, Ligeza & Karska (2003), 72: Bell, Rainger & Hilditch (1990), 73: Vanko & Pribulla (2001), 74: Csák et al (2000), 75: Ahn, Hill & Khalesseh (1992), 76: Yakut, Kalomeni & Ibano?lu (2004), 77: Awadalla & Yamasaki (1984), 78: Awadalla (1989), 79: Binnendijk (1963). …”

Section: Observed Properties Of W Uma‐type Starsmentioning

confidence: 98%

Angular momentum and mass evolution of contact binaries

Gazeas

Stępień

2008

Monthly Notices of the Royal Astronomical Society

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Various scenarios of contact binary evolution have been proposed in the past, giving hints of (sometimes contradictory) evolutionary sequence connecting A-type and W-type systems. As the components of close detached binaries approach each other and contact binaries are formed, following evolutionary paths transform them into systems of two categories: A-type and W-type. The systems evolve in a similar way but under slightly different circumstances. The mass/energy transfer rate is different, leading to quite different evolutionary results. An alternative scenario of evolution in contact is presented and discussed, based on the observational data of over a hundred low-temperature contact binaries. It results from the observed correlations among contact binary physical and orbital parameters. Theoretical tracks are computed assuming angular momentum loss from a system via stellar wind, accompanied by mass transfer from an advanced evolutionary secondary to the main sequence primary. Good agreement is seen between the tracks and the observed graphs. Independently of details of the evolution in contact and a relation between A-type and W-type systems, the ultimate fate of contact binaries involves the coalescence of both components into a single fast rotating star.Comment: 11 pages, 5 figures, a short paragraph added on p. 6, MNRAS, in pres

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“…The mass ratio of BF Pav are from the photometric solution by González et al (1996), and those of V676 Cen, CK Boo, BH Cas, V865 Cyg, V781 Tau, V417 Aql, LT Pav, EK Com, EZ Hya, UW CVn and TZ Boo are from Gray, Woissol & Samec (1996), Krzesinski et al (1991), Metcalfe & Travis (1999), Samec et al (1992), Lu (1993), Samec, Pauley & Carrigan (1997), Cerruti (1994), Samec, Gray & Carrigan (1996), King & Hilditch (1984), Kopacki & Pigulski (1995) and Kaluzny (1985) respectively. Apart from the 12 systems, the values of q of the others are taken from Maceroni & van't Veer (1996).…”

Section: Possible Relation Between the Period Change And The Mass Rmentioning

confidence: 99%

A possible relation between the period change and the mass ratio for W-type contact binaries

Qian

2001

Monthly Notices of the Royal Astronomical Society

129

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Orbital period changes of eight W‐type contact binaries (TY Boo, BH Cas, AD Cnc, TX Cnc, RZ Com, LS Del, BB Peg and AA UMa) are presented based on the analysis of their O–C curves. It is found that the periods of the five systems TY Boo, TX Cnc, RZ Com, LS Del and AA UMa show secular increase. For BB Peg, its period increase rate has been revised. For AD Cnc, weak evidence also shows that its orbital period is increasing. For the remaining BH Cas, the three times of light minimum given by Agerer & Hubscher indicate that, recently, its period has been increasing. However, the properties of the period need further study. The mass ratios of all the systems are larger than 0.4. The period increases of the systems may suggest that the W‐type W UMa stars with high mass ratio usually show their period increase. In order to check this conclusion, secular period changes of 30 W‐type contact binaries have been collected from the literature. It is found that systems showing period increase usually have a higher mass ratio , and the periods of low‐mass ratio systems are varying in a secular decrease. This strongly suggests that a relation between the orbital period variation and the mass ratio for W‐type contact binaries may exist. If the secular period change is caused by conservative mass transfer between the components, this relation may suggest that the evolution of the W‐type systems is oscillation around a critical mass ratio . However this is highly speculative. On the other hand, the relation may be potentially strong observational evidence for Rahunen's conclusion that angular momentum loss (AML) may enable the components of a contact binary to remain in good contact throughout the thermal relaxation oscillation (TRO) cycle. This connection could be explained by the combination of the TRO and the variable AML via the change of depth of contact, which needs further studies observationally and theoretically.

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Contact and near-contact binary systems - II. RR Cen, EZ Hya, V502 Oph and RS Sct

Cited by 25 publications

References 0 publications

On the Period Variation of the W UMa-type Contact Binary V502 Ophiuchi

On the Period Variation of the W UMa-type Contact Binary V502 Ophiuchi

Angular momentum and mass evolution of contact binaries

A possible relation between the period change and the mass ratio for W-type contact binaries

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