Theta Sagittarii

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**θ¹ Sagittarii**
Observation data Epoch J2000.0
Constellation (pronunciation)	Sagittarius
Right ascension	19^h 59^m 44.2^s
Declination	-35° 16' 35"
Apparent magnitude (V)	+4.37
Distance	618 ± 105 ly (189 ± 32 pc)
Spectral type	B2.5IV
Other designations
HR 7623, HD 189103, SAO 211716, HIP 98412

The Bayer designation Theta Sagittarii (θ Sgr / θ Sagittarii) is shared by two star systems, θ¹ Sagittarii and θ² Sagittarii, in the constellation Sagittarius. The two stars are separated by 0.58° on the sky.

[edit] θ¹ Sagittarii

Theta-1 Sagittarii is a spectroscopic binary lying 617 light years from Earth. The primary star, θ¹ Sagittarii A, is a spectral type B2.5 subgiant which has an apparent magnitude of +4.37. The companion star, θ¹ Sagittarii B, is approximately 0.2 arcseconds from the primary, which puts them 31 Astronomical Units (AU) apart (a Sun-Neptune distance).

[edit] θ² Sagittarii

**θ² Sagittarii**
Observation data Epoch J2000.0
Constellation (pronunciation)	Sagittarius
Right ascension	19^h 59^m 51.3^s
Declination	-34° 41' 52"
Apparent magnitude (V)	+5.30
Distance	157 ± 7 ly (48 ± 2 pc)
Spectral type	A4/A5IV
Other designations
HR 7624, HD 189118, SAO 211717, HIP 98421, CCDM 19599-3442

Theta-2 Sagittarii is a triple star system 157 light years from Earth. θ² Sagittarii A is a spectral type A4/5 subgiant which has an apparent magnitude of +5.30. Orbiting the primary with a separation on the sky of 30 arcseconds, or at least 1400 AU, is binary star comprised of θ² Sagittarii B, a magnitude +10.8 star, and θ² Sagittarii C, with a magnitude of +11.5. B and C are 1.2 arcseconds, or approximately 58 AU apart.