Star in the constellation Perseus
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! style="text-align: center; background-color: #FFFFC0;" colspan="2" | Observation dataEpoch J2000      Equinox J2000
! style="text-align:left" | Constellation
! style="text-align:left" | Right ascension
! style="text-align:left" | Declination
! style="text-align:left" | Apparent magnitude (V)
! style="background-color: #FFFFC0; text-align: center;" colspan="2"| Characteristics
! style="text-align:left" | Spectral type
! style="text-align:left" | U−B 
! style="text-align:left" | B−V 
! style="text-align:left" | Variable type
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T Persei is a red supergiant located in the constellation Perseus. It varies in brightness between magnitudes 8.3 and 9.7 and is considered to be a member of the Double Cluster.
T Persei is a member of the Perseus OB1 association around the h and χ Persei open clusters, around 2 degrees north of the centre of the clusters. It is generally treated as an outlying member of the clusters. It lies half a degree away from S Persei, another red supergiant Double Cluster member.
Vojtěch Šafařík discovered that the star is a variable star in 1882. It was listed with its variable star designation, T Persei, in Annie Jump Cannon's 1907 work "Second Catalog of Variable Stars". T Per is a semiregular variable star, whose brightness varies from magnitude 8.34 to 9.7 over a period of 2,430 days. Unlike many red supergiants, it does not appear to have a long secondary period. It is relatively inactive for the red supergiant star, with low mass loss rate /year and no detectable dust shell.
The Washington Double Star Catalog lists T Persei as having a 9th magnitude companion away. This is derived from Hipparcos measurements. However, no other sources report a companion.
References.
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