Pi Persei
Star in the constellation Perseus
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π Persei, Latinized as Pi Persei, is a single[11] star in the northern constellation of Perseus. It has the traditional name Gorgonea Secunda /ɡɔːrɡəˈniːə sɪˈkʌndə/, the second of three Gorgons in the mythology of the hero Perseus.[12] This star has a white hue and is faintly visible to the naked eye with an apparent visual magnitude of +4.7.[2] It is located at a distance of approximately 303 light years from the Sun based on parallax,[1] and is moving further away with a radial velocity of +14 km/s.[4]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Perseus |
| Right ascension | 02h 58m 45.66858s[1] |
| Declination | +39° 39′ 45.8212″[1] |
| Apparent magnitude (V) | 4.70[2] |
| Characteristics | |
| Spectral type | A2Vn[3] |
| U−B color index | +0.12[2] |
| B−V color index | +0.06[2] |
| Astrometry | |
| Radial velocity (Rv) | +14.2[4] km/s |
| Proper motion (μ) | RA: +26.224[1] mas/yr Dec.: −41.899[1] mas/yr |
| Parallax (π) | 10.7797±0.2794 mas[1] |
| Distance | 303 ± 8 ly (93 ± 2 pc) |
| Absolute magnitude (MV) | −0.21[5] |
| Details | |
| Mass | 2.07[6] M☉ |
| Radius | 4.8[7] R☉ |
| Luminosity | 170[8] L☉ |
| Surface gravity (log g) | 3.53[6] cgs |
| Temperature | 9,290[8] K |
| Rotational velocity (v sin i) | 186[8] km/s |
| Age | 272[6] Myr |
| Other designations | |
| Gorgonea Secunda[9], π Per, 22 Persei, BD+39°681, FK5 2207, GC 3567, HD 18411, HIP 13879, HR 879, SAO 56047[10] | |
| Database references | |
| SIMBAD | data |
This object is an A-type main-sequence star with a stellar classification of A2Vn,[3] where the 'n' suffix indicates broad (nebulous) lines due to rapid rotation. It is spinning with a projected rotational velocity of 186 km/s,[8] which is creating an equatorial bulge that is 6% wider than the polar radius.[13] The star is 272[6] million years old with double the mass of the Sun.[6] It has 4.8[7] times the Sun's radius and is radiating 170[8] times the luminosity of the Sun from its photosphere at an effective temperature of 9,290 K.[8]
In Chinese astronomy, this star is named Jīshī (Chinese: 積屍), meaning Heap of Corpses.[14] R. H. Allen transliterated this name as Tseih She and wrongly identified it with Algol.[9][15]