Rho Sagittarii

Rho¹ Sagittari

Location of ρ¹ Sagittarii (circled)

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Sagittarius
Right ascension	19^h 21^m 40.4^s
Declination	−17° 50' 50"
Apparent magnitude (V)	+3.92
Distance	122 ± 3 ly (37 ± 1 pc)
Spectral type	F0III/IV
Other designations
ρ¹ Sagittarii, ρ¹ Sgr, Rho¹ Sgr, 44 Sagittarii, BD-18 5322, GC 26694, HD 181577, HIP 95168, HR 7340, PPM 235882, SAO 162512

The Bayer designation Rho Sagittarii (Rho Sgr, ρ Sagittarii, ρ Sgr) is shared by two stars, ρ¹ Sagittarii and ρ² Sagittarii, in the constellation Sagittarius. The two stars are separated by 0.46° in the sky. Because they are close to the ecliptic, they can be occulted by the Moon and, very rarely, by planets. The next occultation of ρ¹ Sagittarii by a planet will take place on 23 February 2046, when it will be occulted by Venus.

ρ¹ Sagittarii

Rho¹ Sagittarii (Rho¹ Sgr, ρ¹ Sagittarii, ρ¹ Sgr) is a spectral type F0 subgiant which has an apparent magnitude of +3.93. It is 122 light years from Earth.

ρ² Sagittarii

Rho² Sagittari

Location of ρ² Sagittarii (circled)

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Sagittarius
Right ascension	19^h 21^m 50.9^s
Declination	−18° 18' 30"
Apparent magnitude (V)	+5.84
Distance	359 ± 32 ly (110 ± 10 pc)
Spectral type	K0III
Other designations
ρ² Sagittarii, ρ² Sgr, Rho² Sgr, 45 Sagittarii, BD-18 5325, GC 26700, HD 181645, HIP 95188, HR 7344, PPM 235889, SAO 162521.

Rho² Sagittarii (Rho² Sgr, ρ² Sagittarii, ρ² Sgr) is a spectral type K0 giant which has an apparent magnitude of +5.84. It is 359 light years from Earth.

Naming

In Chinese, 建 (Jiàn), meaning Establishment, refers to an asterism consisting of ρ¹ Sagittarii ξ² Sagittarii, ο Sagittarii, π Sagittarii, 43 Sagittarii and υ Sagittarii. Consequently, ρ¹ Sagittarii itself is known as 建五 (Jiàn wǔ, English: the Fifth Star of Establishment.)^[1]

References

1. (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 11 日

• "HD 181577 -- Variable Star". SIMBAD Astronomical Database. Retrieved 2007-03-29.
• "HD 181645 -- Star". SIMBAD Astronomical Database. Retrieved 2007-03-29.