XX Persei (circled) near the Double Cluster and Comet Lovejoy Credit: Juan lacruz | |
Observation data Epoch J2000 Equinox J2000 | |
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Constellation | Perseus |
Right ascension | 02h03m 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 | 6,614+1,060 −812 ly (2,029+325 −249 pc)[5] |
Absolute magnitude (MV) | −4.6[6] |
Details | |
Mass | 16[6] M☉ |
Radius | 718+80 −56[7] R☉ |
Luminosity | 42,000[8] L☉ |
Temperature | 3,339[5] K |
Other designations | |
XX Per, BD+54°444, GSC 03689-01837, HD 12401, HIP 9582, IRC+50052, 2MASS J02030935+5513566, HV 3414, SAO 22875, AAVSO 0156+54 | |
Database references | |
SIMBAD | data |
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.
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.[6] 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.[10]
The most likely distance of XX Per is 2,290 pc, from assumed membership of the Perseus OB1 association.[11] 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.[12][13]
XX Persei has a mass of 16 solar masses, above the limit beyond which stars end their lives as supernovae.[6]
XX Persei is listed in multiple star catalogues with a companion of magnitude 9.8 223″ away.[14] 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.[15]
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