Plate Motion and Earth Orientation

Mallama, Anthony; Kao, M.

doi:10.1017/s0074180900135016

Cited by 2 publications

(2 citation statements)

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“…Gadomski (1932) noticed that the orbital period of the binary was variable. Later, this was confirmed by various investigators (Odinskaya & Ustinov 1951;Lange 1957;Todoran 1963;Mallama 1975;Rovithis-Livaniou & Rovithis 1996). Wood (1950) showed that the period of the eclipsing binary star abruptly increased about JD 2,425,000.…”

Section: Variations In the Orbital Period Of X Trimentioning

confidence: 66%

Orbital Period Studies of Two Algol‐Type Eclipsing Binary Systems: TY Pegasi and X Trianguli

Qian

2002

PUBL ASTRON SOC PAC

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curves of two EA-type eclipsing binaries, TY Peg and X Tri, are formed and studied in O Ϫ C detail based on all available times of light minimum. For TY Peg, it was discovered that the general trend of the curve showed a downward parabolic variation, which indicates a secular period decrease with rate at O Ϫ C days yr Ϫ1 . When the secular decrease is removed from the curve, the residuals can Ϫ6 dP/dt p Ϫ1.16 # 10 O Ϫ C be described by several linear ephemerides, suggesting several sudden period jumps. For the other one, X Tri, it is found that the general trend also indicates a secular period decrease ( days yr Ϫ1 ), Ϫ7O Ϫ C d P /dt p Ϫ1.42 # 10 and several irregular period jumps are found to superpose on the long-time period decrease. This kind of period change, irregular sudden jumps superposed on secular decrease, is typical for many other Algol-type binary systems such as TU Her, UU And, Z Per, Y Psc, BO Mon, FH Ori, RT Per, and TX UMa. The period changes of these systems may be caused by orbital angular momentum loss via variable magnetic coupling and gravity coupling between the components.

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Section: Variations In the Orbital Period Of X Trimentioning

confidence: 66%

Orbital Period Studies of Two Algol‐Type Eclipsing Binary Systems: TY Pegasi and X Trianguli

Qian

2002

PUBL ASTRON SOC PAC

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“…Orbital period changes in TX UMa have been studied by several authors, such as Pearce (1940), Payne-Gaposchkin (1942), Wood (1946), Plavec (1960) and Koch (1961). Kreiner & Tremko Olson (1984Olson ( ) 1969Olson ( -1970 130 H α Grygar, Hric & Komžík (1991) 1969-1973 71 ± 1.5 Rossiter effect Komžík, Chochol & Grygar (2008) 1975 123 ± 4 N a I D Mallama (1978Mallama ( ) 1981 64 C II 1324, 1335Cugier (1989) 1983 40 Mg II 4481 Karetnikov & Kovtyukh (1986) (1980) found that the period had remained constant since 1965. A sudden change around HJD 243 8856 was reported by Oh & Chen (1984).…”

Section: Introductionmentioning

confidence: 99%

TX UMa: new orbit, spin rotation and chemical composition of components

Glazunova

Mkrtichian

Rostopchin³

2011

Monthly Notices of the Royal Astronomical Society

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High‐resolution echelle spectra have been obtained of the semi‐detached Algol‐type eclipsing binary system, TX UMa with the high‐resolution echelle spectrographs of the 1.8 m telescope at Bohyunsan Optical Astronomy Observatory in Korea and of the 2.0 m telescope of Peak Terskol Observatory in Russia. New accurate radial velocities of its components have been measured. With the new measurements, we have been able to infer an improved orbital solution and the masses of the components of the system. For the first time, we have measured the rotational velocity for the Roche lobe filling secondary component. We have concluded that it rotates synchronously, while the rotation of the mass‐accreting primary component is 1.5 times faster than synchronous. TX UMa confirms the previous conclusion that the strong lines of the light elements (N, O, Mg) in the atmospheres of mass‐accreting components in Algol‐type systems are stronger and wider than in single stars of the same spectral class and luminosity. Stronger lines also imply higher elemental abundances than weak lines, but this can also be explained if the former have greater microturbulent velocities. We have suggested that such an excess enhancement of the strong lines may be explained in terms of a distended pseudo‐atmosphere of the mass‐accreting component, engendered by gas flowing in via the L1 Lagrange point. We have found the chemical abundances of 12 elements in the atmosphere of the primary component of TX UMa. Si and Ni were found to show significant deficiencies while the abundance measures of C varied (within the uncertainties of the model atmosphere parameters) from solar to noticeably deficient. Other elements, including He, have solar abundance. The abundances of the secondary component are likely solar, as its spectrum is represented well by a synthetic spectrum with solar abundance and Teff= 5500 K and log g = 3.3.

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Plate Motion and Earth Orientation

Cited by 2 publications

References 1 publication

Orbital Period Studies of Two Algol‐Type Eclipsing Binary Systems: TY Pegasi and X Trianguli

Orbital Period Studies of Two Algol‐Type Eclipsing Binary Systems: TY Pegasi and X Trianguli

TX UMa: new orbit, spin rotation and chemical composition of components

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