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Blue large-amplitude pulsators as a new class of variable stars

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dc.abstract.enRegular intrinsic brightness variations observed in many stars are caused by pulsations. These pulsations provide information on the global and structural parameters of the star. The pulsation periods range from seconds to years, depending on the compactness of the star and properties of the matter that forms its outer layers. Here, we report the discovery of more than a dozen previously unknown short-period variable stars: blue large-amplitude pulsators. These objects show very regular brightness variations with periods in the range of 20-40 min and amplitudes of 0.2-0.4 mag in the optical passbands. The phased light curves have a characteristic sawtooth shape, similar to the shape of classical Cepheids and RR Lyrae-type stars pulsating in the fundamental mode. The objects are significantly bluer than main-sequence stars observed in the same fields, which indicates that all of them are hot stars. Follow-up spectroscopy confirms a high surface temperature of about 30,000 K. Temperature and colour changes over the cycle prove the pulsational nature of the variables. However, large-amplitude pulsations at such short periods are not observed in any known type of stars, including hot objects. Long-term photometric observations show that the variable stars are very stable over time. Derived rates of period change are of the order of 10<SUP>-7</SUP> per year and, in most cases, they are positive. According to pulsation theory, such large-amplitude oscillations may occur in evolved low-mass stars that have inflated helium-enriched envelopes. The evolutionary path that could lead to such stellar configurations remains unknown.
dc.affiliationUniwersytet Warszawski
dc.contributor.authorPietrukowicz, Paweł
dc.contributor.authorDziembowski, Wojciech
dc.contributor.authorLatour, Marilyn
dc.contributor.authorAngeloni, Rodolfo
dc.contributor.authorPoleski, Radosław
dc.contributor.authorMille, Francesco di
dc.contributor.authorSoszyński, Igor
dc.contributor.authorUdalski, Andrzej
dc.contributor.authorSzymański, Michał
dc.contributor.authorWyrzykowski, Łukasz
dc.contributor.authorKozłowski, Szymon
dc.contributor.authorSkowron, Jan
dc.contributor.authorSkowron, Dorota
dc.contributor.authorMróz, Przemysław
dc.contributor.authorPawlak, Michał
dc.contributor.authorUlaczyk, Krzysztof
dc.date.accessioned2024-01-24T18:40:13Z
dc.date.available2024-01-24T18:40:13Z
dc.date.copyright2017-06-22
dc.date.issued2017
dc.description.accesstimeBEFORE_PUBLICATION
dc.description.financeNie dotyczy
dc.description.versionORIGINAL_AUTHOR
dc.description.volume1
dc.identifier.doi10.1038/S41550-017-0166
dc.identifier.urihttps://repozytorium.uw.edu.pl//handle/item/102392
dc.identifier.weblinkhttp://adsabs.harvard.edu/abs/2017NatAs...1E.166P
dc.languageeng
dc.pbn.affiliationastronomy
dc.relation.ispartofNature Astronomy
dc.relation.pages0166
dc.rightsOther
dc.sciencecloudnosend
dc.titleBlue large-amplitude pulsators as a new class of variable stars
dc.typeJournalArticle
dspace.entity.typePublication