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The Question
(Submitted September 13, 2001)
Where is the closest black hole and how far away is it?
The Answer
It is actually difficult to determine the distance to black holes,
but a nearby object believed to be a black hole from observations of strong
X-ray emission is Cygnus X-1, located about 8000 light years away. Cyg X-1
is an ordinary star that is believed to be orbiting a black hole. There
are other nearby candidates for black holes which include :
GRO J0422+32 =V518 Per 1.39 kpc or 2 kpc
A0620-00 = V616 Mon 0.87 kpc or 1.05 kpc
XTE J1118+480 0.83 kpc or 1.8 kpc
(kpc stands for kiloparsec, or approximately 3250 light years)
In fact, you may find a list of such candidates at the following website
under X-ray transients:
http://tonno.tesre.bo.cnr.it/~masetti/sxts.html (http://tonno.tesre.bo.cnr.it/%7Emasetti/sxts.html).
Hope this helps,
Georgia & Koji
For "Ask a High Energy Astronomer"
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