KIC 1718290: A helium-rich V1093-her-like pulsator on the blue horizontal branch

Ostensen RH, Degroote P, Telting JH, Vos J, Aerts C, Jeffery CS, Green EM, Reed MD, Heber U (2012)

Publication Type: Journal article

Publication year: 2012

Journal

Astrophysical Journal Letters American Astronomical Society

Book Volume: 753

Article Number: L17

Journal Issue: 1

DOI: 10.1088/2041-8205/753/1/L17

Abstract

We introduce the first g-mode pulsator found to reside on the classical blue horizontal branch. One year of Kepler observations of KIC1718290 reveals a rich spectrum of low-amplitude modes with periods between 1 and 12 hr, most of which follow a regular spacing of 276.3s. This mode structure strongly resembles that of the V1093Her pulsators, with only a slight shift toward longer periods. Our spectroscopy, however, reveals KIC1718290 to be quite distinct from the sdB stars that show V1093Her pulsations, which all have surface gravities higher than log g= 5.1 and helium abundances depleted by at least an order of magnitude relative to the solar composition. We find that KIC1718290 has T eff= 22,100K, log g= 4.72, and a super-solar helium abundance (log N He/N H= -0.45). This places it well above the extreme horizontal branch, rather on the very blue end of the classical horizontal branch, where shell hydrogen burning is present. We conclude that KIC1718290 must have suffered extreme mass loss during its first giant stage, but not sufficient to reach the extreme horizontal branch. © 2012. The American Astronomical Society. All rights reserved..

Authors with CRIS profile

Ulrich Heber Naturwissenschaftliche Fakultät

Involved external institutions

Katholieke Universiteit Leuven (KUL) / Catholic University of Leuven BE Belgium (BE) Roque de los Muchachos Observatory / Observatorio del Roque de los Muchachos (ORM) ES Spain (ES) Armagh Observatory GB United Kingdom (GB) University of Arizona US United States (USA) (US) Missouri State University US United States (USA) (US)

How to cite

APA:

Ostensen, R.H., Degroote, P., Telting, J.H., Vos, J., Aerts, C., Jeffery, C.S.,... Heber, U. (2012). KIC 1718290: A helium-rich V1093-her-like pulsator on the blue horizontal branch. Astrophysical Journal Letters, 753(1). https://doi.org/10.1088/2041-8205/753/1/L17

MLA:

Ostensen, R. H., et al. "KIC 1718290: A helium-rich V1093-her-like pulsator on the blue horizontal branch." Astrophysical Journal Letters 753.1 (2012).

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