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Titolo: The cessation of eclipses in SS Lacertae: The mystery solved
Autore: Torres, G; Stefanik, RP;
- Indirizzi:
- Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA Harvard Smithsonian Ctr Astrophys Cambridge MA USA 02138 ge, MA 02138 USA
- Titolo Testata:
- ASTRONOMICAL JOURNAL
fascicolo: 4,
volume: 119,
anno: 2000,
pagine: 1914 - 1929
- SICI:
- 0004-6256(200004)119:4<1914:TCOEIS>2.0.ZU;2-W
- Fonte:
- ISI
- Lingua:
- ENG
- Soggetto:
- OPEN CLUSTER NGC-7209; APSIDAL MOTION; SPECTROSCOPIC BINARIES; RADIAL-VELOCITIES; STELLAR MODELS; DI-HERCULIS; SYSTEMS; STARS; PHOTOMETRY; TODCOR;
- Keywords:
- binaries : eclipsing; binaries : spectroscopic; stars : evolution; stars : fundamental parameters; stars : individual (SS Lacertae);
- Tipo documento:
- Article
- Natura:
- Periodico
- Settore Disciplinare:
- Physical, Chemical & Earth Sciences
- Citazioni:
- 71
- Recensione:
- Indirizzi per estratti:
- Indirizzo: Torres, G Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA Harvard Smithsonian Ctr Astrophys 60 Garden St Cambridge MA USA 02138
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- Citazione:
- G. Torres e R.P. Stefanik, "The cessation of eclipses in SS Lacertae: The mystery solved", ASTRONOM J, 119(4), 2000, pp. 1914-1929
Abstract
The 14.4 day period eclipsing binary SS Lacertae in the open cluster NGC 7209 is unusual in that the eclipses stopped completely about the middle of this century, giving rise to considerable speculation as to the cause. Disruption of the binary through a collision with another member of the clusterand, more likely, gravitational perturbations from a third star in the system have been proposed to explain the phenomenon. We present here the results of our intensive radial velocity monitoring of the object, which show clearly that there is indeed a third star in the system in a slightly eccentric orbit with a period of about 679 days. We also reanalyze the historical light curves of SS Lac to determine the properties of the system early in the century. We discuss the implications of our findings in terms of changesin the inclination angle of the close pair. An analysis of available timesof eclipse for SS Lac together with the new velocity information has also revealed apsidal motion in the system, (omega) over dot = 0.degrees 0137 cycle(-1), corresponding to an apsidal period of about 1000 yr. We argue thatthe third star is probably responsible for this effect also.
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Documento generato il 25/05/13 alle ore 17:41:56