Search results
Results from the WOW.Com Content Network
Red supergiants develop deep convection zones reaching from the surface over halfway to the core and these cause strong enrichment of nitrogen at the surface, with some enrichment of heavier elements. [26] Some red supergiants undergo blue loops where they temporarily increase in temperature before returning to the red supergiant state. This ...
Post-red supergiant stars have a generally higher level of nitrogen relative to carbon due to convection of CNO-processed material to the surface and the complete loss of the outer layers. Surface enhancement of helium is also stronger in post-red supergiants, representing more than a third of the atmosphere. [28] [29]
Red giants vary in the way by which they generate energy: most common red giants are stars on the red-giant branch (RGB) that are still fusing hydrogen into helium in a shell surrounding an inert helium core; red-clump stars in the cool half of the horizontal branch, fusing helium into carbon in their cores via the triple-alpha process
Rare blue supergiant stars are some of the hottest, brightest stars in the universe. But other distant supernovas have shown that before they exploded, stars ejected dense clouds decades beforehand.
XX Per is a red supergiant of spectral type M4Ib with an effective temperature below 4,000 K. It has a large infrared excess, indicating surrounding dust at a temperature of 900 K, but no masers have been detected. [14] [15] XX Persei has a mass of 16 solar masses, above the limit beyond which stars end their lives as supernovae. [6]
V762 Cassiopeiae is a red supergiant and a variable star located about 2,500 light-years away in the Cassiopeia constellation. Its apparent magnitude vary between 5.82 and 5.95, which makes it faintly visible to the naked eye under dark skies. It is a relatively cool star with an average surface temperature of 3,869 K.
VY Canis Majoris is a candidate for a star in a second red supergiant phase, but this is mostly speculative and unconfirmed. [66] From this star CO emission is coincident with the bright KI shell in its asymmetric nebula. The star will produce either: a moderately luminous and long-lasting type IIn supernova (SN IIn) a hypernova; or a
Characteristics [ edit ] PZ Cassiopeiae is a luminous red supergiant star, one of the largest stars currently known with a radius over 1,200 times the Sun's radius ( R ☉ ), and also one of the most luminous of its type, around 240,000 times more luminous than the Sun ( L ☉ ). [ 10 ]