eta Carinae Emerging from the X-ray Minimum
ATel #6453; Michael F. Corcoran (NASA/GSFC-CRESST/USRA), Jamar Liburd (U. VI), Kenji Hamaguchi (NASA/GSFC-CRESST/UMBC), Theodore Gull (NASA/GSFC), Thomas Madura (NASA/GSFC/NPP), Mairan Teodoro (NASA/GSFC/CNPq), Anthony Moffat and Noel Richardson (U. Montreal), Chris Russell (U. Delaware), Andrew Pollock (ESA), Stan Owocki (U. Delaware)
on 7 Sep 2014; 00:35 UT
Credential Certification: Michael Corcoran (michael.f.corcoran@nasa.gov)
Subjects: X-ray, Binary, Star, Variables
Analysis of eta Car's X-ray spectrum in the 2-10 keV band using quicklook data from the X-ray Telescope on Swift shows that the flux on September 5 and 6, 2014 was approximately 2.3±0.3×10-11 ergs s-1cm-2. This flux is very close to the X-ray flux seen by RXTE in 2009 at a similar phase in the X-ray cycle, and about a factor of 1.8 larger than the flux seen at this phase in the X-ray minima of 2003.5 and 1998. The Swift observations show that eta Car is emerging from its current X-ray minimum (see ATEL #6357). The X-ray flux increase shows no significant difference from the flux recovery seen during the last X-ray minimum in 2009. This is in contrast to the difference in the behavior of the He II 4687 line between the current cycle and the 2009 cycle noted in ATEL #6408, which was interpreted to indicate an earlier recovery of the X-ray flux compared to the 2009 cycle. If the X-ray flux continues to follow the 2009 trend, then we expect that the 2-10 X-ray flux will increase in the coming two weeks (see ATEL #6448) and fully recover by October 1 to a flux level near 10-10 ergs s-1cm-2 in the 2-10 keV band.
