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HD 99458: First time ever Ap-type star as a δ Scuti pulsator in a short period eclipsing binary?

Marek SkarkaAstronomical Institute, Czech Academy of Sciences, Fričova 298, CZ-25165 Ondřejov, Czech RepublicP. KábathAstronomical Institute, Czech Academy of Sciences, Fričova 298, CZ-25165 Ondřejov, Czech RepublicE. PaunzenDepartment of Theoretical Physics and Astrophysics, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech RepublicM. FedurcoFaculty of Science, P. J. Šafárik University, Park Angelinum 9, Košice 04001, Slovak RepublicJ. BudajAstronomical Institute of the Slovak Academy of SciencesDaniel DupkalaAstronomical Institute, Charles University, Faculty of Mathematics and Physics, CZ-18000 Praha 8 V Holešovičkách 2, Czech RepublicJiřı́ KrtičkaDepartment of Theoretical Physics and Astrophysics, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech RepublicA. P. HatzesThüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg, GermanyT. PribullaAstronomical Institute of the Slovak Academy of SciencesŠ. ParimuchaFaculty of Science, P. J. Šafárik University, Park Angelinum 9, Košice 04001, Slovak RepublicZdeněk MikulášekDepartment of Theoretical Physics and Astrophysics, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech RepublicE. W. GuentherThüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg, GermanyS. SabottaThüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg, GermanyMartin BlažekDepartment of Theoretical Physics and Astrophysics, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech RepublicJ. DvořákováAstronomical Institute, Czech Academy of Sciences, Fričova 298, CZ-25165 Ondřejov, Czech RepublicĽ. HambálekAstronomical Institute of the Slovak Academy of SciencesT. KlocováAstronomical Institute, Czech Academy of Sciences, Fričova 298, CZ-25165 Ondřejov, Czech RepublicVojtech KollárAstronomical Institute of the Slovak Academy of SciencesE. KundraAstronomical Institute, Slovak Academy of Sciences, 05960 Tatranská Lomnica, Slovak RepublicM. ŠlechtaAstronomical Institute, Czech Academy of Sciences, Fričova 298, CZ-25165 Ondřejov, Czech RepublicM. VaňkoAstronomical Institute, Slovak Academy of Sciences, 05960 Tatranská Lomnica, Slovak Republic

2019en

ABI

Annotatsiya

We present the discovery of a unique object, a chemically peculiar Ap-type star showing Scuti pulsations that is bound in an eclipsing binary system with an orbital period shorter than 3 d. 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 d is the second shortest among all known chemically peculiar (CP2) binary stars. Pulsations of 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 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 ) on an inclined orbit (i = 73.2(6) deg) 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.

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Identifikatorlar

DOI: 10.1093/mnras/stz1478

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