XX Persei (IRC +50052 / HIP 9582 / BD+54°444) is a semiregular variable red supergiant star in the constellation Perseus, between the Double Cluster and the border with Andromeda.
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Perseus |
Right ascension | 02h 03m 09.35854s[1] |
Declination | 55° 13′ 56.6229″[1] |
Apparent magnitude (V) | 7.9 - 9.0[2] |
Characteristics | |
Spectral type | M4Ib + B7V[3] |
Variable type | SRc[4] |
Astrometry | |
Proper motion (μ) | RA: −1.263[1] mas/yr Dec.: −1.819[1] mas/yr |
Parallax (π) | 0.3980 ± 0.0316 mas[1] |
Distance | 8,200 ± 700 ly (2,500 ± 200 pc) |
Absolute magnitude (MV) | −4.6[5] |
Details | |
Mass | 16[5] M☉ |
Radius | 548[6] - 681[7] R☉ |
Luminosity | 42,000[6] L☉ |
Temperature | 3,535±170[6] K |
Other designations | |
Database references | |
SIMBAD | data |
XX Persei is a semiregular variable star of sub-type SRc, indicating a cool supergiant. The General Catalogue of Variable Stars gives the period as 415 days.[4] It also shows a long secondary period which was originally given at 4,100 days.[5] A more recent study shows only slow variations with a period of 3,150 ± 1,000 days.[2] Another study failed to find any long period up to 10,000 days.[9]
The most likely distance of XX Per is 2,290 pc, from assumed membership of the Perseus OB1 association.[10]Gaia Data Release 3 includes a parallax of 0.3980±0.0316 mas, corresponding to a distance of around 2,500 pc.[1]
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.[11][12]
XX Persei has a mass of 16 solar masses, above the limit beyond which stars end their lives as supernovae.[5]
XX Persei is listed in multiple star catalogues with a companion of magnitude 9.8 223″ away.[13] This star is BD+54°445 and it is an unrelated foreground object. In addition, the spectrum of XX Persei shows absorption lines of a hot companion too close to be resolved. The combined spectral type has been given as M4Ib + B7V,[3] while the UV spectrum of the companion has been used to derive a spectral classification of A.[14]