Theta Andromedae
Template:Location mark Location of θ Andromedae (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[1] |
| Apparent magnitude (V) | 4.61[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | A2 V[4] |
| U−B Template:Engvar | +0.05[2] |
| B−V Template:Engvar | +0.06[2] |
| Variable type | Constant[5] |
| Astrometry | |
| Radial velocity (Rv) | 0.9[6] km/s |
| Proper motion (μ) | RA: Script error: No such module "val".[1] mas/yr Dec.: Script error: No such module "val".[1] mas/yr |
| Parallax (π) | 18.8747±0.4251 mas[1] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | −0.25[7] |
| Orbit[8] | |
| Period (P) | Script error: No such module "val". days |
| Semi-major axis (a) | Script error: No such module "val". mas |
| Eccentricity (e) | Script error: No such module "val". |
| Inclination (i) | Script error: No such module "val".° |
| Longitude of the node (Ω) | Script error: No such module "val".° |
| Periastron epoch (T) | Script error: No such module "val". |
| Argument of periastron (ω) (secondary) | Script error: No such module "val".° |
| Details | |
| A | |
| Mass | Script error: No such module "val".[3] Template:Solar mass |
| Luminosity | 113[7] Template:Solar luminosity |
| Surface gravity (log g) | 3.95[9] cgs |
| Temperature | 8,960[9] K |
| Metallicity [Fe/H] | +0.14[9] dex |
| Rotational velocity (v sin i) | 102[3] km/s |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| Template:Odlist[10] | |
| Database references | |
| SIMBAD | data |
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Theta Andromedae is a binary star[11] system in the northern constellation of Andromeda. Theta Andromedae, Latinized from θ Andromedae, is its Bayer designation. It is located at a distance of approximately Script error: No such module "convert". from the Sun,[1] and has an apparent visual magnitude of 4.6.[2] On the Bortle Dark-Sky Scale, this makes it visible to the naked eye from outside urban regions. Based on its motion through space, this system appears to be a member of the Sirius supercluster.[12]
The brighter component is a white hued A-type main-sequence star with a stellar classification of A2 V.[4] It is one of the least photometrically variable stars known.[5] The star shows a high rate of rotation with a projected rotational velocity of 102 km/s.[3] It has an estimated 2.8[3] times the mass of the Sun and is radiating 113[7] times the Sun's luminosity from its photosphere at an effective temperature of 8,960 K.[9] The relatively high chemical abundances of iron and heavier elements suggests it may be a fast rotating Am star.[5]
A stellar companion was detected in 1986 and reported in 1989.[13] This fainter companion is separated from Theta Andromedae by 0.06 arcseconds.[11] The secondary appears to be a massive, possibly A-type, star orbiting at a distance of around one astronomical unit with a period of Script error: No such module "convert". and a large orbital eccentricity (ovalness) of 0.95.[8]
Naming
In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Celestial Stable, refers to an asterism consisting of θ Andromedae, ρ Andromedae and σ Andromedae. Consequently, the Chinese name for θ Andromedae itself is known as Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx.)[14]
References
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- ↑ a b c d e f Template:Cite Gaia EDR3
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- ↑ a b c Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "citation/CS1".
- ↑ a b c d Script error: No such module "citation/CS1".
- ↑ Template:Cite simbad
- ↑ a b Script error: No such module "citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 18 日 Template:Webarchive
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