New Light Curves and Orbital Solution for AM Leonis

Hiller, M. E.; Osborn, W.; Terrell, Dirk

doi:10.1086/383098

Cited by 19 publications

(17 citation statements)

References 35 publications

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“…A period increase near 1985 was discovered by , and several possible mechanisms (e.g., mass transfer, third body, magnetic activity cycles , internal mass motions) were proposed to explain the O À C oscillation by them. Our two eclipse times and those times of minimum light published by Pribulla et al (2002), Agerer & Hübscher (2003), Gürol et al (2003), Dvorak (2004), and Hiller et al (2004) reveal that the period of AM Leo has been increasing recently. This indicates that the period change of the binary system needs to be investigated in detail.…”

Section: Introductionsupporting

confidence: 74%

“…Therefore, only PC observations were used for the present period study. As shown in Figure 4, after the period increase reported by , another period increase occurred around HJD 2,450,800 and was also reported by Hiller et al (2004). By assuming that the period change is not continuous, the O À C curve can be divided into four portions (AB, BC, CD, and DE) in which the period change is discussed.…”

Section: Variations In O à C For Am Leonismentioning

confidence: 59%

“…Following this collection, some times of minimum light were compiled by Hiller et al (2004) and at the Eclipsing Binaries Minima Database (EBMD).…”

Section: Variations In O à C For Am Leonismentioning

confidence: 99%

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Period Changes of AO Camelopardalis and AM Leonis and Their Implications for the Presence of Tertiary Components and the Evolutionary States of the Two Overcontact Binary Systems

Qian

Fang

et al. 2005

Astron J

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AO Cam and AM Leo are two short-period overcontact binary systems whose physical properties are nearly the same. In the present paper, three CCD times of minimum light for AO Cam and two photoelectric eclipse times for AM Leo are presented. Combining the new determined eclipse times with others compiled from the literature, the behavior of their O À C variations were investigated. For AO Cam, its orbital period is revised, and it is found that the period shows a cyclic variation with a period of 20.1 yr and an amplitude of 0.0047 days. In AM Leo, a new period increase has occurred recently. Two possibilities of period variations, sudden and continuous changes, are discussed. The period changes of both systems cannot be explained by apsidal motion, since both the primary and the secondary eclipse times vary in the same O À C trend. Of the three mechanisms of magnetic activity cycles, internal mass motions, and the presence of a third body, we think that the last is more plausible. Assuming that the period changes are due to third bodies revolving around the eclipsing pairs, the parameters of the third-component stars are determined. If it exists, the third body in AO Cam is revolving in a circular orbit, whereas that in AM Leo is revolving in an eccentric orbit (e 0 ¼ 0:58). No secular period changes were discovered in either overcontact binary star, which is in agreement with the recent statistical relation of Qian. This may suggest that AO Cam and AM Leo are in transition between the angular momentum loss-controlled and the thermal relaxation oscillation-controlled stages of the evolutionary scheme recently proposed by Qian.

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Section: Introductionsupporting

confidence: 74%

Section: Variations In O à C For Am Leonismentioning

confidence: 59%

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Period Changes of AO Camelopardalis and AM Leonis and Their Implications for the Presence of Tertiary Components and the Evolutionary States of the Two Overcontact Binary Systems

Qian

Fang

et al. 2005

Astron J

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“…

The eclipsing variable star AM Leo (BD +10• 2234 A) is a bright component (V = 9.1− 9.7 mag) of the visual binary system ADS 8024 (ρ = 11′′ .4, θ = 270 • ) (Hiller et al 2004). The most comprehensive survey of the photometric observations of AM Leo were given in the studies of Hiller et al (2004) and Albayrak et al (2005a).

…”

mentioning

confidence: 99%

“…′′ .4, θ = 270 • ) (Hiller et al 2004). The most comprehensive survey of the photometric observations of AM Leo were given in the studies of Hiller et al (2004) and Albayrak et al (2005a).…”

mentioning

confidence: 99%

New Light-Time Curve of Eclipsing Binary AM Leo

Gorda¹,

Matveeva²

2017

IBVS

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The eclipsing variable star AM Leo (BD +10• 2234 A) is a bright component (V = 9.1− 9.7 mag) of the visual binary system ADS 8024 (ρ = 11′′ .4, θ = 270 • ) (Hiller et al. 2004). The most comprehensive survey of the photometric observations of AM Leo were given in the studies of Hiller et al. (2004) and Albayrak et al. (2005a). Many authors noted temporal variations in the light curve of AM Leo. Along with the light curve variations, orbital variations have been observed too. Various hypotheses were proposed to explain this phenomenon. The most likely reason for the period change in AM Leo is now considered to be the presence of a third body in the system. This hypothesis was first suggested by Demircan & Derman (1992) The CCD observations data were reduced using the MaxImDL and Muniwin (http://cmunipack.sourceforge.net) packages. The minima time were computed by a parabola fitting method and averaged from all filters used during the night. Values of the moments of

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Light‐time effect in the eclipsing binary system AM Leonis

Albayrak¹,

Selam

et al. 2005

Astron Nachr

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Abstract. We report four new times of minimum light and the improved ephemeris for the well known contact binary AM Leo. The O-C diagram, constructed with all reliable timings found in the literature was analyzed and the the light-time effect in the system was confirmed. We found a periodicity of 44.82 years in the O-C residuals with an amplitude of 0.0058 day. The periodic curve representing the O-C values is asymmetric indicating a large eccentricity of 0.73 of the third body orbit. The mass of the third body is found to be 0.175 M for the orbital inclination of the eclipsing pair's orbit.

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New Light Curves and Orbital Solution for AM Leonis

Cited by 19 publications

References 35 publications

Period Changes of AO Camelopardalis and AM Leonis and Their Implications for the Presence of Tertiary Components and the Evolutionary States of the Two Overcontact Binary Systems

Period Changes of AO Camelopardalis and AM Leonis and Their Implications for the Presence of Tertiary Components and the Evolutionary States of the Two Overcontact Binary Systems

New Light-Time Curve of Eclipsing Binary AM Leo

Light‐time effect in the eclipsing binary system AM Leonis

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