Phi Andromedae
Template:Location mark Location of φ Andromedae (upper left). | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[1] |
| Apparent magnitude (V) | 4.25[2] (4.46/6.06)[3] |
| Characteristics | |
| Spectral type | B7 Ve[4] + B9 V[3] |
| U−B Template:Engvar | −0.34[2] |
| B−V Template:Engvar | −0.07[2] |
| R−I Template:Engvar | −0.05 |
| Astrometry | |
| Radial velocity (Rv) | −0.1[5] km/s |
| Proper motion (μ) | RA: +4.05[1] mas/yr Dec.: −12.43[1] mas/yr |
| Parallax (π) | 4.55±0.60 mas[1] |
| Distance | approx. Template:Rnd ly (approx. Template:Rnd pc) |
| Absolute magnitude (MV) | −2.41[6] |
| Details | |
| φ And A | |
| Luminosity | 882[6] Template:Solar luminosity |
| Surface gravity (log g) | 3.150[7] cgs |
| Temperature | 13490[7] K |
| Rotational velocity (v sin i) | 75[8] km/s |
| Age | 63.1 ± 13.7[9] Myr |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| 42 Andromedae, ADS 940, BD+46 275, HD 6811, HIP 5434, HR 335, SAO 36972, PPM 43693[10] | |
| Database references | |
| SIMBAD | data |
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Phi Andromedae (φ Andromedae, φ And) is the Bayer designation for a binary star[3] system near the border of the northern constellation of Andromeda. This system has a combined apparent visual magnitude of 4.25[2] and is visible to the naked eye. Based upon parallax measurements made during the Hipparcos mission, this star system is located at a distance of about Script error: No such module "convert". from Earth.[1]
Nomenclature
In Chinese astronomy, φ Andromedae forms the single-star asterism Jūnnánmén (軍南門 or 军南门, "Southern Military Gate").[11][12] R. H. Allen's Star Names refers to this asterism as Keun Nan Mun, "the Camp's South Gate", and includes χ Andromedae in it,[13] but in Chinese sources χ Andromedae is a member of the Tian Dajiangjun (Heaven's Great General) asterism.[14] Another identification of Jūnnánmén is α Trianguli.[12]
Components
The 4.46[3] magnitude primary component is a Be star with a stellar classification of B7 Ve, indicating that it is a B-type main sequence star that shows prominent emission lines of hydrogen in its spectrum. These emission lines come from a flattened decretion disk of hot gas that is orbiting the host star.[4] The star is rotating rapidly with a projected rotational velocity of 75 km/s.[8] The pole of the star is inclined around 20° to the line of sight from the Earth.[4]
The 6.06 magnitude companion star is a B-type main sequence star with a classification of B9 V. On average the two stars are separated by about 0.6 arcseconds and have an orbital period of roughly 554 years. Based upon their orbital elements, the system has a combined mass of around Script error: No such module "val". times the mass of the Sun.[15]
References
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- ↑ Script error: No such module "citation/CS1".. Accessed 2007-05-14.
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- ↑ Template:Cite simbad
- ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 9 日 Template:Webarchive
- ↑ a b Script error: No such module "citation/CS1".
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- ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日 Template:Webarchive
- ↑ Script error: No such module "citation/CS1".
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