Helium-weak stars arechemically peculiarstars which have a weakhelium lines for theirspectral type.^[1][2] Their helium lines place them in a later (i.e. cooler) spectral type than theirhydrogen lines.^[3]

Helium-weak stars are mid-to-late B-class stars with weaker than normal spectral lines of neutral helium, compared to normal stars with similar hydrogen line strengths. These are considered to be an extension of theAp/Bp chemically-peculiar stars with slightly hotter temperatures. They often show similar increased abundances of heavy elements. The mechanism of atmospheric stratification of elements is thought to be responsible for both types of chemical peculiarity.^[4][5]

This is a non-extensive list of helium-weak stars.^[6][7]

This list isincomplete; you can help byadding missing items.(June 2019)

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.^[8] The following are examples:

• HD 37017 A
• HD 144941
• HR 7355
• Sigma Lupi
• V2052 Ophiuchi

V761 Centauri (a Centauri) is well-known for both thevariability of its brightness and of its helium spectral lines. Stars of this type are referred to as helium-variable. This is thought to occur when one hemisphere of the star's atmosphere is helium-weak and one is helium-strong.^[9]

• Helium star
• Extreme helium star

• Helium-weak stars

• Articles with short description
• Short description matches Wikidata
• Incomplete lists from June 2019