Back to Search Start Over

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

Authors :
Martin Vaňko
Jan Budaj
Theodor Pribulla
Marek Skarka
Jiří Krtička
Miroslav Šlechta
L. Hambálek
Eike W. Guenther
S. Sabotta
Miroslav Fedurco
Daniel Dupkala
Ernst Paunzen
Petr Kabath
Artie P. Hatzes
Emil Kundra
Martin Blažek
V. Kollár
Štefan Parimucha
Tereza Klocova
Zdeněk Mikulášek
Jana Dvořáková
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

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