The pulsation properties of lambda bootis stars I. the southern TESS sample

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F20%3A00116124" target="_blank" >RIV/00216224:14310/20:00116124 - isvavai.cz</a>

Result on the web

<a href="https://academic.oup.com/mnras/article-abstract/495/2/1888/5834555" target="_blank" >https://academic.oup.com/mnras/article-abstract/495/2/1888/5834555</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1093/mnras/staa1271" target="_blank" >10.1093/mnras/staa1271</a>

Result language

angličtina

Original language name

The pulsation properties of lambda bootis stars I. the southern TESS sample

Original language description

We analyse TESS light curves for 70 southern lambda Boo stars to identify binaries and to determine which of them pulsate as delta Scuti stars. We find two heartbeat stars and two eclipsing binaries among the sample. We calculate that 81 per cent of lambda Boo stars pulsate as delta Sct variables, which is about twice that of normal stars over the same parameter space. We determine the temperatures and luminosities of the lambda Boo stars from photometry and Gaia DR2 parallaxes. A subset of 40 lambda Boo stars have 2-min TESS data, reliable temperatures and luminosities, and delta Sct pulsation. We use Petersen diagrams (period ratios), echelle diagrams, and the periodluminosity relation to identify the fundamental mode in 20 of those 40 stars and conclude that a further 8 stars are not pulsating in this mode. For the remaining 12, the fundamental mode cannot be unambiguously identified. Further mode identification is possible for 12 of the fundamental mode pulsators that have regular sequences of pulsation overtones in their echelle diagrams. We use stellar evolutionmodels to determine statistically that the lambda Boo stars are only superficially metal weak. Simple pulsation models also better fit the observations at a metallicity of Z = 0.01 than at Z = 0.001. The TESS observations reveal the great potential of asteroseismology on lambda Boo stars, for determining precise stellar ages and shedding light on the origin(s) of the lambda Boo phenomenon.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2020

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Monthly Notices of the Royal Astronomical Society

ISSN

0035-8711

e-ISSN

1365-2966

Volume of the periodical

495

Issue of the periodical within the volume

2

Country of publishing house

GB - UNITED KINGDOM

Number of pages

25

Pages from-to

1888-1912

UT code for WoS article

000543015800025

EID of the result in the Scopus database

2-s2.0-85095536018