Talk:GRO J1655-40

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[edit] To merge?

The following material was submitted by 58.106.10.99 at AfC and contains substantial differences to this article. Perhaps an expert would like to merge the useful parts into the article?


GRO J1655-40 is a Black Hole, a microquasar 10,000 light years from Earth. A microquasar is a type of black hole with jets of high-speed particles shooting perpendicularly from the plane of matter that orbits it.

This Black Hole is approaching our planet at a speed of 250,000 miles an hour, luckily it's many light years away and won't reach us for another 30,000 years.

Matter can orbit GRO J1655-40 relatively stably but occasionally it wobbles at certain precise frequencies. This supposedly is a result of how the black hole deforms space and time in a four-dimensional concept that Einstein called spacetime.

The black hole was formed in the disk at a distance greater than 3 kpc from the Galactic centre and must have been shot to such an eccentric orbit by the explosion of the progenitor star. The runaway linear momentum and kinetic energy of this black hole binary are comparable to those of solitary neutron stars and millisecond pulsars. GRO J1655-40 is the first black hole for which there is evidence for a runaway motion imparted by a natal kick in a supernova explosion.

GRO J1655-40 was recently used to prove that Black Holes spin.

[edit] Sources

OK, thanks, I will see about merging the information provided into the article. I'm not a super expert on this object either, but I can see that this user's info is older than mine (AfC was dated 10/16/2005), and at least I am currently working in the field. I'll have to check sources, etc. Best, Bill Wwheaton (talk) 03:52, 1 May 2008 (UTC)
Following up on this. According to Mirabel et al 2002[1]the space velocity is 118+/-18 km/s, but proper motion is 5.2±0.5 mas/yr, based on HST astrometry. Thus it is not moving directly at us. They find an eccentric galactic orbit, e = 0.34±0.05; the eccentricity uncertainty is dominated by the distance uncertainty, 0.9-3.2 kpc. The orbit never exceeds 150 pc from the galactic plane, and does not approach the galactic center closer than ~3.9 kpc. The space velocity does indicate a likely supernova origin. That the binary survived the SN is interesting. Spectroscopic binary velocity semi-amplitude is approx 228 km/s, radial velocity -142.4 km/s[2]. Wwheaton (talk) 00:56, 15 May 2008 (UTC)

[edit] Needs work

I do not have time to follow-up now, but the references I have indicate the data in the article may be untrustworthy. Distance of 0.9-3.9 kpc is highly uncertain. SIMBAD gives no info that I can see on radial velocity or proper motion, but Orosz & Bailyn 1997 ApJ 477,876 quote -142.4 km/s radial velocity, and Mirabel et al 2002 A&A 395,595 quote proper motion of 5.2±0.5 mas/yr. Optical spectrum of F4IV should give temperature of around 6000-7500 K I think. Wwheaton (talk) 01:15, 15 May 2008 (UTC)

I have tentatively changed the article to reflect the above, pending further investigation of the literature. Wwheaton (talk) 01:49, 15 May 2008 (UTC)