Theta Andromedae
 Location of θ Sagittarii (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Andromeda |
| Right ascension | 00h 17m 05.49885s[1] |
| Declination | +38° 40′ 53.8902″[1] |
| Apparent magnitude (V) | 4.61[2] |
| Characteristics | |
| Spectral type | A2 V[3] |
| U−B color index | +0.05[2] |
| B−V color index | +0.06[2] |
| Astrometry | |
| Radial velocity (Rv) | 0.9[4] km/s |
| Proper motion (μ) | RA: –49.35[1] mas/yr Dec.: -17.65[1] mas/yr |
| Parallax (π) | 10.56 ± 0.96[1] mas |
| Distance | 310 ± 30 ly (95 ± 9 pc) |
| Orbit[5] | |
| Period (P) | 1033+91 −77 days |
| Semi-major axis (a) | 25+32 −13 mas |
| Eccentricity (e) | 0.95+0.04 −0.40 |
| Inclination (i) | 69+8 −22° |
| Longitude of the node (Ω) | 263+50 −156° |
| Periastron epoch (T) | 238+343 −143 |
| Argument of periastron (ω) (secondary) |
89+175 −29° |
| Details | |
| Surface gravity (log g) | 3.95[6] cgs |
| Temperature | 8960[6] K |
| Metallicity [Fe/H] | +0.14[6] dex |
| Rotational velocity (v sin i) | 102[7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Theta Andromedae (θ And, θ Andromedae) is the Bayer designation for a binary star in the constellation Andromeda. It is approximately 310 light-years (95 parsecs) from Earth,[1] with a visual magnitude of 4.6.[2] On the Bortle Dark-Sky Scale, this makes it visible to the naked eye from outside urban regions.
Theta Andromedae is a white A-type main sequence dwarf with an apparent magnitude of +4.61. It appears to be a binary star with a massive, possibly A-type secondary orbiting at a distance of around 1 astronomical unit.[5] A fainter companion is separated from Theta Andromedae by 0.06 arcseconds.[8]
Naming
In Chinese, 天廄 (Tiān Jiù), meaning Celestial Stable, refers to an asterism consisting of θ Andromedae, ρ Andromedae and σ Andromedae. Consequently, θ Andromedae itself is known as 天廄一 (Tiān Jiù yī, English: the First Star of Celestial Stable.)[9]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 2.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 5.0 5.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 6.0 6.1 6.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 18 日
External links
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