Xi Boötis
| Xi Boötis A | |
| Stellar characteristics | |
|---|---|
| Constellation | Boötis |
| Right ascension (Epoch J2000) | 14h 51m 23.3785s |
| Declination (Epoch J2000) | +19° 06′ 01.656″ |
| Spectral type | G8 Ve |
| Distance from Sol | 21.9 ± 0.1 ly |
| Other designations | Xi or Chi or Ksi Boo, 37 Boo, HR 5544, Gl 566 A, Hip 72659, HD 131156, BD+19 2870, SAO 101250, Struve 1888 A, ADS 9413 A. |
| Xi Boötis B | |
| Stellar characteristics | |
|---|---|
| Constellation | Boötis |
| Right ascension (Epoch J2000) | 14h 51m 23.3785s |
| Declination (Epoch J2000) | +19° 06′ 01.656″ |
| Spectral type | K4-5 Ve |
| Distance from Sol | 21.9 ± 0.1 ly |
| Other designations | Gl 566 B, Struve 1888 B, ADS 9413 B. |
(Data from SolStation.com)
Also known as Ksi Boötis, this possible triple star system is located about 21.8 light-years (ly) away from our Sun, Sol. It lies in the southeastern corner of the constellation Boötes, the Herdsman or Bear Driver. It is a well known and attractive, visual binary pair of a bright yellow star and a reddish-violet to pink companion and was discovered in 1780 by Sir William Herschel (1738-1822) Although smaller and dimmer than Sol, Xi Boötis is visible to the naked eye.
According to new measurements[1] found in the new Sixth Catalog of Visual Orbits of Binary Stars, star A and B are separated by an "average distance" of about 33.6 AUs (semi-major axis of 4.94" with a HIPPARCOS parallax of 0.14710 +/- 0.00080"). They move in an elliptical orbit (e= 0.51) that takes about 151.6 years to complete, travelling as close as 16.5 AUs and as far away as 50.7 AUs. Their orbit is inclined about 139° from the perspective of an observer on Earth.
Xi Boötis A
Xi Boötis A is a yellow-orange main sequence dwarf star of spectral and luminosity type G8 Ve. It may have 90 to 94 percent (+/- 20 percent) of Sol's mass [2], 89 percent of its diameter [3], and about 49 percent of its luminosity. It may be somewhat less enriched as Sol with elements heavier than hydrogen ("metallicity") based on the ionization balance of iron and a comparison between observed and computed profiles for the extremely strong ionized calcium <re>(Ruck and Smith, 1995)</ref> -- metallicity measurements based on iron alone range from 55 to 155 percent of Sol's [4]. While strong chromospheric activity suggest that the star may be as young as 60 million years [5], the lack of an easily observable dust disk suggests that the stars may be well over a billion years old. Xi Bootis A is classified as a BY Draconis type, rotating variable star whose visual magnitude varies from 4.52 to 4.67 over 10.137 days.
Xi Boötis B
Xi Boötis B is an orange-red main sequence dwarf star of spectral and luminosity type K4-5 Ve. This star may have 67 to 76 percent of Sol's mass[6], 71 percent of its diameter[7], and about 6.1 percent of its luminosity.
Notes
- Jump up ↑ (Staffan Soderhjelm, 1999)
- Jump up ↑ (RECONS; and Daniel M. Popper, 1980, page 36)
- Jump up ↑ (Johnson and Wright, 1983, page 681)
- Jump up ↑ (Cayrel de Strobel et al, 1991, page 26)
- Jump up ↑ (see HD 131156 A in Table 2 from Don Barry, 1988)
- Jump up ↑ (RECONS)
- Jump up ↑ (Johnson and Wright, 1983, page 681)
