The Formation of Blue Large-amplitude Pulsators from White-dwarf Main-sequence Star Mergers
Blue large-amplitude pulsators (BLAPs) are hot low-mass stars that show large-amplitude light variations likely due to radial oscillations driven by iron group opacities. Period changes provide evidence of both secular contraction and expansion among the class. Various formation histories have been...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad0a65 |
| _version_ | 1797435158296526848 |
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| author | Xianfei Zhang C. Simon Jeffery Jie Su Shaolan Bi |
| author_facet | Xianfei Zhang C. Simon Jeffery Jie Su Shaolan Bi |
| author_sort | Xianfei Zhang |
| collection | DOAJ |
| description | Blue large-amplitude pulsators (BLAPs) are hot low-mass stars that show large-amplitude light variations likely due to radial oscillations driven by iron group opacities. Period changes provide evidence of both secular contraction and expansion among the class. Various formation histories have been proposed, but none are completely satisfactory. Zhang et al. proposed that the merger of a helium-core white dwarf with a low-mass main-sequence star (HeWD+MS) can lead to the formation of some classes of hot subdwarfs. We have analyzed these HeWD+MS merger models in more detail. Between helium-shell ignition and full helium-core burning, the models pass through the volume of luminosity–gravity–temperature space occupied by BLAPs. Periods of expansion and contraction associated with helium-shell flashes can account for the observed rates of period change. We argue that the HeWD+MS merger model provides at least one BLAP formation channel. |
| first_indexed | 2024-03-09T10:43:11Z |
| format | Article |
| id | doaj.art-14143e0cada94cb4bc311b838e3299eb |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-09T10:43:11Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-14143e0cada94cb4bc311b838e3299eb2023-12-01T11:50:28ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195912410.3847/1538-4357/ad0a65The Formation of Blue Large-amplitude Pulsators from White-dwarf Main-sequence Star MergersXianfei Zhang0https://orcid.org/0000-0002-3672-2166C. Simon Jeffery1https://orcid.org/0000-0003-1759-0302Jie Su2https://orcid.org/0000-0001-7566-9436Shaolan Bi3https://orcid.org/0000-0002-7642-7583Institute for Frontier in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of China ; zxf@bnu.edu.cn; Department of Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of ChinaArmagh Observatory and Planetarium, College Hill, Armagh BT61 9DG, UKYunnan Observatories, Chinese Academy of Sciences, Kunming 650216, People’s Republic of China; Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650216, People’s Republic of China; International Centre of Supernovae , Yunnan Key Laboratory, Kunming 650216, People’s Republic of ChinaInstitute for Frontier in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of China ; zxf@bnu.edu.cn; Department of Astronomy, Beijing Normal University , Beijing 100875, People’s Republic of ChinaBlue large-amplitude pulsators (BLAPs) are hot low-mass stars that show large-amplitude light variations likely due to radial oscillations driven by iron group opacities. Period changes provide evidence of both secular contraction and expansion among the class. Various formation histories have been proposed, but none are completely satisfactory. Zhang et al. proposed that the merger of a helium-core white dwarf with a low-mass main-sequence star (HeWD+MS) can lead to the formation of some classes of hot subdwarfs. We have analyzed these HeWD+MS merger models in more detail. Between helium-shell ignition and full helium-core burning, the models pass through the volume of luminosity–gravity–temperature space occupied by BLAPs. Periods of expansion and contraction associated with helium-shell flashes can account for the observed rates of period change. We argue that the HeWD+MS merger model provides at least one BLAP formation channel.https://doi.org/10.3847/1538-4357/ad0a65Stellar evolutionStellar evolutionary modelsBinary starsStellar abundancesBlue large-amplitude pulsatorsStellar mergers |
| spellingShingle | Xianfei Zhang C. Simon Jeffery Jie Su Shaolan Bi The Formation of Blue Large-amplitude Pulsators from White-dwarf Main-sequence Star Mergers The Astrophysical Journal Stellar evolution Stellar evolutionary models Binary stars Stellar abundances Blue large-amplitude pulsators Stellar mergers |
| title | The Formation of Blue Large-amplitude Pulsators from White-dwarf Main-sequence Star Mergers |
| title_full | The Formation of Blue Large-amplitude Pulsators from White-dwarf Main-sequence Star Mergers |
| title_fullStr | The Formation of Blue Large-amplitude Pulsators from White-dwarf Main-sequence Star Mergers |
| title_full_unstemmed | The Formation of Blue Large-amplitude Pulsators from White-dwarf Main-sequence Star Mergers |
| title_short | The Formation of Blue Large-amplitude Pulsators from White-dwarf Main-sequence Star Mergers |
| title_sort | formation of blue large amplitude pulsators from white dwarf main sequence star mergers |
| topic | Stellar evolution Stellar evolutionary models Binary stars Stellar abundances Blue large-amplitude pulsators Stellar mergers |
| url | https://doi.org/10.3847/1538-4357/ad0a65 |
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