Theta Andromedae

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Template:Short description

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: Template:Val[1] mas/yr
Dec.: Template:Val[1] mas/yr
Parallax (π)18.8747±0.4251 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)−0.25[7]
Orbit[8]
Period (P)Template:Val days
Semi-major axis (a)Template:Val mas
Eccentricity (e)Template:Val
Inclination (i)Template:Val°
Longitude of the node (Ω)Template:Val°
Periastron epoch (T)Template:Val
Argument of periastron (ω)
(secondary)		Template:Val°
Details
A
MassTemplate:Val[3] Template:Solar mass
Luminosity113[7] Template:Solar luminosity
Surface gravity (log g)3.95[9] cgs
Temperature8,960[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
SIMBADdata

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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 Template: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 Template: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

Template:Reflist

External links

Template:Stars of Andromeda

  1. ↑ a b c d e f Cite error: Invalid <ref> tag; no text was provided for refs named Gaia EDR3
  2. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named clpl4_99
  3. ↑ a b c d e Cite error: Invalid <ref> tag; no text was provided for refs named Zorec_Royer_2012
  4. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named aj74_375
  5. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named Koçer_et_al_2003
  6. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named rgcrv
  7. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named Anderson2012
  8. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named apjss166_1_341
  9. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named aaa294_2_536
  10. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named SIMBAD
  11. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named mnras389_2_869
  12. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Palous_Hauck_1986
  13. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named McAlister_et_al_1989
  14. ↑ 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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