Omicron Persei
Triple star system in the constellation Perseus
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Omicron Persei (ο Persei, abbreviated Omicron Per, ο Per) is a triple star system in the constellation of Perseus. From parallax measurements taken during the Hipparcos mission it is approximately 1,100 light-years (330 parsecs) from the Sun.
 | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Perseus |
| A | |
| Right ascension | 03h 44m 19.13377s[1] |
| Declination | +32° 17′ 17.6874″[1] |
| Apparent magnitude (V) | 3.83[2] |
| B | |
| Right ascension | 03h 44m 19.17122s[3] |
| Declination | +32° 17′ 18.5103″[3] |
| Apparent magnitude (V) | 6.68[4] |
| Characteristics | |
| A | |
| Spectral type | B1III / B2V[5] |
| U−B color index | −0.75[2] |
| B−V color index | +0.05[2] |
| Variable type | ellipsoidal[6] |
| Astrometry | |
| Radial velocity (Rv) | +12.20[7] km/s |
| Absolute magnitude (MV) | −4.4[5] |
| A | |
| Proper motion (μ) | RA: +6.091[1] mas/yr Dec.: −9.732[1] mas/yr |
| Parallax (π) | 3.0224±0.3827 mas[1] |
| Distance | approx. 1,100 ly (approx. 330 pc) |
| Orbit[5] | |
| Primary | Aa |
| Name | Ab |
| Period (P) | 4.4191447 days |
| Semi-major axis (a) | 33 R☉ |
| Eccentricity (e) | 0.0 |
| Inclination (i) | 39±15° |
| Semi-amplitude (K1) (primary) | 111.8 km/s |
| Semi-amplitude (K2) (secondary) | 155.0 km/s |
| Details | |
| Aa | |
| Mass | 14[8] M☉ |
| Radius | 9.6[5] R☉ |
| Surface gravity (log g) | 3.4[8] cgs |
| Temperature | 22,700[8] K |
| Rotational velocity (v sin i) | 70±5[5] km/s |
| Ab | |
| Mass | 10[8] M☉ |
| Radius | 8.9[5] R☉ |
| Surface gravity (log g) | 4.0[8] cgs |
| Temperature | 21,000[8] K |
| Rotational velocity (v sin i) | 65±15[5] km/s |
| Age | 15[5] Myr |
| Other designations | |
| Atik, 38 Persei, ADS 2726 AB, BD+31°642, CCDM J03443+3217AB, GC 4461, GSC 02359-01258, HIP 17448, HR 1131, HD 23180, SAO 56673, WDS J03443+3217AB | |
| Database references | |
| SIMBAD | data |
The system consists of a spectroscopic binary pair designated Omicron Persei A and a third companion Omicron Persei B.[9] A's two components are themselves designated Omicron Persei Aa (officially named Atik /ˈeɪtɪk/, the traditional name of the system)[10][11] and Ab.
Etymology
ο Persei (Latinised to Omicron Persei) is the system's Bayer designation. The designations of the two constituents as Omicron Persei A and B, and those of A's components - Omicron Persei Aa and Ab - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[12]
It bore the traditional name Atik (also Ati, Al Atik), Arabic for "the shoulder". Some sources attribute the name Atik to the nearby, brighter star Zeta Persei.[13][14] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[15] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[16] It approved the name Atik for the component Omicron Persei A on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.[11]
In Chinese, 卷舌 (Juǎn Shé), meaning Rolled Tongue, refers to an asterism consisting of Omicron Persei, Nu Persei, Epsilon Persei, Xi Persei, Zeta Persei and 40 Persei.[17] Consequently, the Chinese name for Omicron Persei itself is 卷舌五 (Juǎn Shé wu), "the Fifth Star of Rolled Tongue".[18]
Properties
Omicron Persei A is a spectroscopic binary consisting of a spectral type B1 giant and a type B2 dwarf orbiting each other every 4.4 days. The orbit is near-circular although its inclination is not precisely known. The two stars are separated by approximately 33 R☉, the exact value depending on the inclination. The primary is approximately one magnitude brighter than the secondary at visual wavelengths.[5] The binary pair forms a rotating ellipsoidal variable star, which varies in brightness from visual magnitude 3.79 to 3.88 during the orbital period.[20]
Omicron Persei lies just north of the open cluster IC 348, but is not catalogued as a member. Both IC 348 and Omicron Persei belong to the Perseus OB2 association.[21]
Culture
- In the TV series Futurama, the fictional planet Omicron Persei 8 is home to medicinal plants and reptilian extraterrestrials who often attack Earth.[22][23]
- The USS Atik, named for Omicron Persei Aa, was a ship of the United States Navy.