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 then their hydrogen lines.[3]
List of helium-weak stars
[edit]This is a non-extensive list of helium-weak stars.[4][5]
Star Name | Constellation | Apparent Magnitude (mv) | 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
[edit]A related class of stars have anomalously strong helium lines in their spectra, and are known as helium-strong stars.[1]
See also
[edit]References
[edit]- ^ 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.
Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
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