Theta Sagittae

θ Sagittae
Location of θ Sagittae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Sagitta
A
Right ascension 20h 09m 56.6470s[1]
Declination +20° 54′ 54.094″[1]
Apparent magnitude (V) +6.516[2]
B
Right ascension 20h 09m 56.2405s[3]
Declination +20° 55′ 04.228″[3]
Apparent magnitude (V) +8.769[2]
Characteristics
A
Spectral type F3V[4]
U−B color index −0.04[5]
B−V color index +0.38[5]
B
Spectral type G5V[6]
B−V color index +0.732[2]
Astrometry
A
Radial velocity (Rv)−40.92[1] km/s
Proper motion (μ) RA: +58.387[1] mas/yr
Dec.: +98.274[1] mas/yr
Parallax (π)22.3262 ± 0.0326 mas[1]
Distance146.1 ± 0.2 ly
(44.79 ± 0.07 pc)
Absolute magnitude (MV)+3.24[7]
B
Radial velocity (Rv)−43.0[8] km/s
Proper motion (μ) RA: +64.726[3] mas/yr
Dec.: +101.800[3] mas/yr
Parallax (π)22.3841 ± 0.0305 mas[3]
Distance145.7 ± 0.2 ly
(44.67 ± 0.06 pc)
Absolute magnitude (MV)+5.58[7]
Details
A
Mass1.52[9] M☉
Radius1.45[1] R☉
Luminosity4.0[1] L☉
Surface gravity (log g)4.32[9] cgs
Temperature6,750±229[9] K
Metallicity [Fe/H]−0.17[8] dex
Rotational velocity (v sin i)33.6[10] km/s
Age2.089[9] Gyr
B
Mass0.95[11] M☉
Radius0.82[3] R☉
Luminosity0.516[3] L☉
Surface gravity (log g)4.526[12] cgs
Temperature5,394[3] K
Other designations
θ Sge, 17 Sge, BD+20°4453, HD 191570, WDS J20099+2055[13]
A: HIP 99352, HR 7705, SAO 88276
B: HIP 99351, SAO 88275
Database references
SIMBADA
B

Theta Sagittae (θ Sagittae) is a double star in the northern constellation of Sagitta.[14] With a combined apparent visual magnitude of +6, it is near the limit of stars that can be seen with the naked eye. According to the Bortle scale the star is visible in dark suburban/rural skies. Based upon an annual parallax shift of 22.15 mas as seen from Earth,[15] it is located roughly 147 light years from the Sun.

The binary pair consists of two stars separated by 502 AU.[16] The primary, component A,[17] is an F-type main sequence star with a stellar classification of F3V.[4] This star is about two billion years old[9] with 52% more mass than the Sun.[9] It forms a double star with a magnitude 8.85 companion,[17] which is located at an angular separation of 11.58 arc seconds along a position angle of 331.1°, as of 2011.[14] The star is sometimes described as a triple star, with a 7th magnitude companion 91″ away.[17] This is an unrelated giant star much further away than the close pair.[18] A fainter star separated by nearly 3′ was also listed as a companion by Struve,[17] again just an accidental optical association.[19]

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  7. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Casagrande2011 was invoked but never defined (see the help page).
  9. ^ a b c d e f Cite error: The named reference David2015 was invoked but never defined (see the help page).
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  14. ^ a b Cite error: The named reference Mason2012 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
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  17. ^ a b c d Cite error: The named reference WDSC2014 was invoked but never defined (see the help page).
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  19. ^ Cite error: The named reference dr2d was invoked but never defined (see the help page).