New Observations Indicate G2 Cloud Has not Yet Reached Orbital Pericenter

Observations reported in the Astronomers Telegram on June 30th by astronomers Eckart, et al. indicate that the G2 cloud is still on its way inward toward the Galactic core and hence has not yet reached its orbital pericenter; see report here:

http://www.astronomerstelegram.org/?read=6285.

Late last year Gillessen et al. (2013) had made calculations of the orbital characteristics of the G2 cloud and had estimated that the G2 cloud would reach its point of closest approach to the Galactic core around April 1st, i.e., over three months ago.  But now observations carried out by Eckart, et al. suggest differently.  They see that the emission from the cloud is still largely redshifted, hence that the cloud is still heading away from us toward the GC.  This could explain why the Galactic core has been so quiet up until now.  They do not update the existing orbital characteristics to suggest when the cloud may be reaching its point of closest approach and an email I sent to them asking about this went unanswered.  When I have more information, I will post it.  Meanwhile we should again be alert to look for any evidence of the G2 cloud being split in two after it rounds orbital pericenter.

Secondly, and no relation to the above observation, Eckart also report that they observe the cloud is still compact, that it has not dispersed.  To remain compact while being exposed to the high velocity gas flow from the Galactic core the G2 cloud would need to be continually regenerated from an embedded star or binary star system.  In a paper published in December 2012 Echart, et al. was one who had suggested the possibility that the G2 cloud may contain an embedded star, corroborating my suggestion posted around that time.

 

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