Xi Sagittarii

Xi¹ Sagittari

Location of ξ¹ Sagittarii (circled)

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Sagittarius
Right ascension	18^h 57^m 20.5^s
Declination	−20° 39' 23"
Apparent magnitude (V)	+5.02
Distance	> 2300 ly (> 700 pc)
Spectral type	B9.5Ib
Other designations
ξ¹ Sagittarii, ξ¹ Sgr, Xi¹ Sgr, 36 Sagittarii, BD-20 5339, GC 26012, HD 175687, HIP 93057, HR 7145, PPM 269124, SAO 187498.

The Bayer designation Xi Sagittarii (Xi Sgr, ξ Sagittarii, ξ Sgr) is shared by two stars, ξ¹ Sagittarii and ξ² Sagittarii, in the constellation Sagittarius, 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 last occultation of ξ² Sagittarii by a planet took place on 22 December 1810, when it was occulted by Venus.

ξ¹ Sagittarii

Xi¹ Sagittarii (Xi¹ Sgr, ξ¹ Sagittarii, ξ¹ Sgr) is a spectral type B9.5 supergiant which has an apparent magnitude of +5.08. It is at least 2300 light years from Earth.

ξ² Sagittarii

Xi² Sagittari

Location of ξ² Sagittarii (circled)

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Sagittarius
Right ascension	18^h 57^m 43.8^s
Declination	−21° 06' 24"
Apparent magnitude (V)	+3.52
Distance	372 ± 42 ly (114 ± 13 pc)
Spectral type	G8/K0II/III
Other designations
ξ² Sagittarii, ξ² Sgr, Xi² Sgr, 37 Sagittarii, BD-21 5201, FK5 710, GC 26019, HD 175775, HIP 93085, HR 7150, PPM 269132, SAO 187504,

Xi² Sagittarii (Xi² Sgr, ξ² Sagittarii, ξ² Sgr) is a spectral type G8 or K0 giant which has an apparent magnitude of +3.52. It is 372 light years from Earth.

Naming

In Chinese, 建 (Jiàn), meaning Establishment, refers to an asterism consisting of ξ² Sagittarii, ο Sagittarii, π Sagittarii, 43 Sagittarii, ρ¹ Sagittarii and υ Sagittarii. Consequently, ξ² Sagittarii itself is known as 建一 (Jiàn yī, English: the First 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 175687 -- High proper-motion Star". SIMBAD Astronomical Database. Retrieved 2007-03-29.
• "HD 175775 -- High proper-motion Star". SIMBAD Astronomical Database. Retrieved 2007-03-29.