V4641 Sagittarii
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 19m 21.63s |
| Declination | −25° 24′ 25.8″ |
| Other designations | |
| Database references | |
| SIMBAD | data |
V4641 Sagittarii (V4641 Sgr) is a variable X-ray binary star system in the constellation Sagittarius. It is the source of one of the fastest superluminal jets in our galaxy.
In 1999 a violent X-ray outburst revealed it to contain a black hole.[1] At the time, it was considered to be the closest known black hole to Earth, at a distance of approximately 1,600 light-years (490 pc). Later observations showed it to be at least 15 times farther away.[2]
References
- ↑ "Dramatic Outburst Reveals Nearest Black Hole". National Radio Astronomy Observatory. Retrieved 2008-08-30.
- ↑ A Black Hole in the Superluminal Source SAX J1819.3-2525 (V4641 SGR), 2001: "Finally, we find a distance in the range 7.40 ≤ d ≤ 12.31 kpc (90% confidence), which is at least a factor of ≈ 15 larger than the initially assumed distance of ≈ 1,600 light-years/500 pc."
External links
Coordinates: 
18h 19m 21.636s, −25° 24′ 25.6″
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