15 Sagittae
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Star 15 sagittae |
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| AladinLite | |||||||||||||||||
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | arrow | ||||||||||||||||
| Right ascension | 20 h 04 m 6.22 s | ||||||||||||||||
| declination | + 17 ° 04 ′ 12.6 ″ | ||||||||||||||||
| Apparent brightness | 5.8 likes | ||||||||||||||||
| Typing | |||||||||||||||||
| B − V color index | +0.61 | ||||||||||||||||
| U − B color index | +0.09 | ||||||||||||||||
| Spectral class | G0 V | ||||||||||||||||
| Astrometry | |||||||||||||||||
| Radial velocity | (+4.8 ± 0.1) km / s | ||||||||||||||||
| parallax | (56.6 ± 0.8) mas | ||||||||||||||||
| distance | (57.6 ± 0.8) ly (17.7 ± 0.2) pc |
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| Proper movement | |||||||||||||||||
| Rec. Share: | (−394 ± 0.64) mas / a | ||||||||||||||||
| Dec. portion: | (−406 ± 0.63) mas / a | ||||||||||||||||
| Physical Properties | |||||||||||||||||
| radius | 1.1 R ☉ | ||||||||||||||||
| Effective temperature | 5940 K | ||||||||||||||||
| Age | 1 to 3 billion a | ||||||||||||||||
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Other names and catalog entries |
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15 Sagittae (short 15 Sge ) is a main sequence star of the spectral class G0 in the constellation Arrow, about 58 light years away from Earth . With an apparent magnitude of 5.8 mag, it can only be seen with the naked eye under optimal conditions. The star is accompanied by an L-dwarf named 15 Sagittae B.
Cool companion
15 Sagittae B , also Gliese 779 B and HR 7672 B , is a presumably substellar L-dwarf. Its spectral class is estimated to be L6 ± 1.5 and a mass of about 60 to 70 Jupiter masses is derived from models. Under certain assumptions, the effective temperature is at 1510-1850 K appreciated. The angular distance to the central star is 0.79 ", which when projected corresponds to a distance of about 14 astronomical units . The object was discovered in 2002 by Liu et al. At the Mauna Kea Observatory .
Web links
- SIMBAD
- Extrasolar Visions ( Memento from July 16, 2012 in the Internet Archive )
Individual evidence
- ↑ a b c d e SIMBAD database
- ↑ a b Bright Star Catalog
- ↑ a b Hipparcos catalog
- ↑ Liu, MC et al .: Crossing the brown dwarf desert using adaptive optics: a very close L dwarf companion to the nearby solar analog HR 7672 . In: Astrophysical Journal . tape 571 , May 2002, p. 519-527 .