Helium-weak star

Helium-weak stars are chemically peculiar stars which have a weak helium lines for their spectral type.^[1]^[2] Their helium lines place them in a later (i.e. cooler) spectral type than their hydrogen lines.^[3]

List of helium-weak stars

This is a non-extensive list of helium-weak stars.^[4]^[5]

Caption text
Star Name	Constellation	Apparent Magnitude (m_v)	Class	Notes
20 Eridani (EG Eridani)	Eridanus	5.23	B8/9 III	α² CVn variable
30 Capricorni	Capricornus	5.38	B5 II/III
θ Hydri	Hydrus	5.50	B8 III/IV	Suspected Binary;
22 Eridani (FY Eridani)	Eridanus	5.53	B9 IIIpSi (4200)	α² CVn variable
HD 74196	Vela	5.61	B7 Vn	Part of IC 2391
HD 28843 (DZ Eridani)	Eridanus	5.81	B9 III	SX Arietis variable
12 Canis Majoris (HK Canis Majoris)	Canis Major	6.08	B7 II/III	SX Arietis variable
HD 34797 (TX Leporis)	Lepus	6.54	B7 Vp	α² CVn variable; binary
HD 35456	Orion	6.95	B9 II/III	Binary

Helium-strong star

A related class of stars have anomalously strong helium lines in their spectra, and are known as helium-strong stars.^[1] These are the more massive stars with classes of B1 to B3, compared to the helium-weak stars with classes of B5 to B9.^[6] The following are examples:

References

^ ^a ^b Landstreet, J. D.; Bohlender, David A. (1988). "Abundance and Magnetic Field Geometries of Helium-Strong and Helium-Weak Stars". Symposium - International Astronomical Union. 132: 309–312. Bibcode:1987BAAS...19..704B. doi:10.1017/S0074180900035191. ISSN 0074-1809.
^ Preston, George W. (1974). "The Chemically Peculiar Stars of the Upper Main Sequence". Annual Review of Astronomy and Astrophysics. 12 (1): 257–277. Bibcode:1974ARA&A..12..257P. doi:10.1146/annurev.aa.12.090174.001353.
^ "A Digital Spectral Classification Atlas - R. O. Gray". ned.ipac.caltech.edu. Retrieved 2019-05-31.
^ Jaschek, Mercedes; Jaschek, Carlos; Arnal, Marcelo (October 1969). "Helium-Weak Stars". Publications of the Astronomical Society of the Pacific. 81 (482): 651. Bibcode:1969PASP...81..650J. doi:10.1086/128832.
^ Alonso, M. S.; López-García, Z.; Malaroda, S.; Leone, F. (April 2003). "Elemental abundance studies of CP stars. The helium-weak stars HD 19400, HD 34797 and HD 35456*". Astronomy and Astrophysics. 402: 331. Bibcode:2003A&A...402..331A. doi:10.1051/0004-6361:20030222.
^ Faltová, N.; Kallová, K.; Prišegen, M.; Staněk, P.; Supíková, J.; Xia, C.; Bernhard, K.; Hümmerich, S.; Paunzen, E. (December 2021). "A case study of ACV variables discovered in the Zwicky Transient Facility survey". Astronomy & Astrophysics. 656. id. A125. arXiv:2108.11411. Bibcode:2021A&A...656A.125F. doi:10.1051/0004-6361/202141534.

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[lanstreet1974-1] Landstreet, J. D.; Bohlender, David A. (1988). "Abundance and Magnetic Field Geometries of Helium-Strong and Helium-Weak Stars". Symposium - International Astronomical Union. 132: 309–312. Bibcode:1987BAAS...19..704B. doi:10.1017/S0074180900035191. ISSN 0074-1809.

[2] Preston, George W. (1974). "The Chemically Peculiar Stars of the Upper Main Sequence". Annual Review of Astronomy and Astrophysics. 12 (1): 257–277. Bibcode:1974ARA&A..12..257P. doi:10.1146/annurev.aa.12.090174.001353.

[3] "A Digital Spectral Classification Atlas - R. O. Gray". ned.ipac.caltech.edu. Retrieved 2019-05-31.

[4] Jaschek, Mercedes; Jaschek, Carlos; Arnal, Marcelo (October 1969). "Helium-Weak Stars". Publications of the Astronomical Society of the Pacific. 81 (482): 651. Bibcode:1969PASP...81..650J. doi:10.1086/128832.

[5] Alonso, M. S.; López-García, Z.; Malaroda, S.; Leone, F. (April 2003). "Elemental abundance studies of CP stars. The helium-weak stars HD 19400, HD 34797 and HD 35456*". Astronomy and Astrophysics. 402: 331. Bibcode:2003A&A...402..331A. doi:10.1051/0004-6361:20030222.

[6] Faltová, N.; Kallová, K.; Prišegen, M.; Staněk, P.; Supíková, J.; Xia, C.; Bernhard, K.; Hümmerich, S.; Paunzen, E. (December 2021). "A case study of ACV variables discovered in the Zwicky Transient Facility survey". Astronomy & Astrophysics. 656. id. A125. arXiv:2108.11411. Bibcode:2021A&A...656A.125F. doi:10.1051/0004-6361/202141534.

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List of helium-weak stars

Helium-strong star

See also

References