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HD 99458: First time ever Ap-type star as a δ Scuti pulsator in a short period eclipsing binary?
- Source :
- Monthly Notices of the Royal Astronomical Society. 487:4230-4237
- Publication Year :
- 2019
- Publisher :
- Oxford University Press (OUP), 2019.
-
Abstract
- We present the discovery of a unique object, a chemically peculiar Ap-type star showing $\delta$ Scuti pulsations which is bound in an eclipsing binary system with an orbital period shorter than 3 days. HD 99458 is, therefore, a complex astrophysical laboratory opening doors for studying various, often contradictory, physical phenomena at the same time. It is the first Ap star ever discovered in an eclipsing binary. The orbital period of 2.722 days is the second shortest among all known chemically peculiar (CP2) binary stars. Pulsations of $\delta$ Scuti type are also extremely rare among CP2 stars and no unambiguously proven candidate has been reported. HD 99458 was formerly thought to be a star hosting an exoplanet, but we definitely reject this hypothesis by using photometric observations from the K2 mission and new radial velocity measurements. The companion is a low-mass red dwarf star ($M_{2}=0.45(2)$ M$_{\odot}$) on an inclined orbit ($i=73.2(6)$ degrees) that shows only grazing eclipses. The rotation and orbital periods are synchronized, while the rotation and orbital axes are misaligned. HD 99458 is an interesting system deserving of more intense investigations.<br />Comment: 8 pages, 4 figures, 4 tables, accepted in MNRAS
- Subjects :
- Physics
Inclined orbit
Red dwarf
010308 nuclear & particles physics
Astronomy and Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
Orbital period
01 natural sciences
Exoplanet
Radial velocity
Stars
Astrophysics - Solar and Stellar Astrophysics
Space and Planetary Science
0103 physical sciences
Binary star
Astrophysics::Solar and Stellar Astrophysics
Astrophysics::Earth and Planetary Astrophysics
Binary system
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
Subjects
Details
- ISSN :
- 13652966 and 00358711
- Volume :
- 487
- Database :
- OpenAIRE
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Accession number :
- edsair.doi.dedup.....428310b4f41ccba5e0092314e7fe46dd
- Full Text :
- https://doi.org/10.1093/mnras/stz1478