B, V, R, I light curves of the very short-period binary AD CANCRI

Samec, R. G.; Bookmyer, B. B.

doi:10.1086/132117

Cited by 6 publications

(18 citation statements)

References 3 publications

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“…Efremov et al (1964) suspected that AD Cancri is a W UMa type system with twice the period given by Kurochkin (1960), which was confirmed by Samec & Bookmyer (1987), who published the first complete light curves in the B, V, R, and I bands. An approximate check by Samec & Bookmyer (1987) indicated that AD Cancri is not a member of M67 but is several hundred parsecs closer than this cluster. The photometric data of Samec & Bookmyer (1987) were later analyzed by Samec et al (1989) with the Wilson-Devinney method (e.g., Wilson & Devinney1971).…”

Section: Introductionmentioning

confidence: 90%

“…A complete light curve in the V band was obtained on 2002 February 7, and complete light curves in the V and R bands were obtained on 2004 December 20. They are displayed in Figures 1 and 2, with the phases of those observations being calculated using the orbital period given by Samec & Bookmyer (1987) Tables 1-3: the Heliocentric Julian Dates and phases, and the magnitude differences between AD Cancri and the comparison star. By using a parabolic fitting method, 13 epochs of minimum light, spanning a time interval of about 5 years, were determined and are listed in Table 4.…”

Section: Ccd Photometric Observations and The Changes Of The Light Curvementioning

confidence: 99%

“…Also shown in Figure 1 are the light curves in the V band published by Yang & Liu (2002) and by Samec & Bookmyer (1987). Since the V light curve obtained in 2004 shows a slightly large scatter, it is not displayed in this figure.…”

Section: Ccd Photometric Observations and The Changes Of The Light Curvementioning

confidence: 99%

“…An approximate check by Samec & Bookmyer (1987) indicated that AD Cancri is not a member of M67 but is several hundred parsecs closer than this cluster. The photometric data of Samec & Bookmyer (1987) were later analyzed by Samec et al (1989) with the Wilson-Devinney method (e.g., Wilson & Devinney1971). They showed that AD Cancri is a contact binary with a mass ratio of q ¼ 0:635.…”

Section: Introductionmentioning

confidence: 96%

“…The spectral type of the variable was determined to be K0 by Herbig (as cited in Samec & Bookmyer 1987), which was in agreement with the B À V color range of 0.89-0.94 given by Millis (1972). Efremov et al (1964) suspected that AD Cancri is a W UMa type system with twice the period given by Kurochkin (1960), which was confirmed by Samec & Bookmyer (1987), who published the first complete light curves in the B, V, R, and I bands. An approximate check by Samec & Bookmyer (1987) indicated that AD Cancri is not a member of M67 but is several hundred parsecs closer than this cluster.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

AD Cancri: A Shallow Contact Solar‐Type Eclipsing Binary and Evidence for a Dwarf Third Component and a 16 Year Magnetic Cycle

Qian

Yuan

Soonthornthum

et al. 2007

ApJ

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Variations of the light levels at the primary minimum and both maxima are found. Uniform solutions of four sets of photometric data were derived by using the Wilson-Devinney method. The solutions suggest that AD Cancri is a shallow W-type contact binary ( f ¼ 8:3% AE 1:3%) with a high mass ratio of 1/q ¼ 0:770 AE 0:002. The long-term variation of the light curve is explained by variable dark-spot models of the more massive component star with a possible 17 yr cycle. Our 13 times of light minimum over 5 years, including others collected from the literature, have been used for the period study. The complex period changes can be sorted into a long-term period increase at rate of dP/dt ¼ þ(4:94 AE 0:16) ; 10 À7 days yr À1 , a 16.2 yr periodic component (A 3 ¼ 0:0155 days), and a very small amplitude period oscillation (A 4 ¼ 0:0051 days, P 4 ¼ 6:6 yr). The existence of third light may indicate that there is a tertiary component in the binary system. Solving the four-band light curves of Samec & Bookmyer, it is found that the contribution of the tertiary component to the total light of the triple system increases with wavelength, which suggests that it is very cool and may be a very red main-sequence star. The small-amplitude period oscillation may be caused by the light-time effect of the cool tertiary component (M 3 $ 0:41 M ). The 16.2 yr periodic component in the orbital period and the 17 yr cyclic activity of the dark spot on the more massive component both may reveal that the more massive component displays solar-type magnetic activity with a cycle length of about 16 yr.

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Section: Introductionmentioning

confidence: 90%

Section: Ccd Photometric Observations and The Changes Of The Light Curvementioning

confidence: 99%

Section: Ccd Photometric Observations and The Changes Of The Light Curvementioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

AD Cancri: A Shallow Contact Solar‐Type Eclipsing Binary and Evidence for a Dwarf Third Component and a 16 Year Magnetic Cycle

Qian

Yuan

Soonthornthum

et al. 2007

ApJ

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show abstract

Period-finding methods, techniques and applications to variable stars observations

Alawy

1995

Astrophys Space Sci

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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

122

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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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B, V, R, I light curves of the very short-period binary AD CANCRI

Cited by 6 publications

References 3 publications

AD Cancri: A Shallow Contact Solar‐Type Eclipsing Binary and Evidence for a Dwarf Third Component and a 16 Year Magnetic Cycle

AD Cancri: A Shallow Contact Solar‐Type Eclipsing Binary and Evidence for a Dwarf Third Component and a 16 Year Magnetic Cycle

Period-finding methods, techniques and applications to variable stars observations

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

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