Outburst of CI Cam - B[e] /X ray

[Francois Teyssier]

Optical outburst of the B[e]/X-Ray system CI Cam/XTE J0421+560

ATel #9634; M. J.P. Wijngaarden (University of Amsterdam), K. Gourdji (University of Amsterdam), L. C. Oostrum (ASTRON/University of Amsterdam), H. F. Henrichs (University of Amsterdam)
on 16 Oct 2016; 00:41 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Huib Henrichs (h.f.henrichs@uva.nl)


Subjects: Radio, Far-Infra-Red, Infra-Red, Optical, Ultra-Violet, X-ray, Gamma Ray, Request for Observations, Binary, Black Hole, Nova, Neutron Star, Star, Transient, Variables



We report a very strong optical outburst of the B[e]/transient X-ray system CI Cam/XTE J0421+560. On 2016 Oct 09.064 we measured H alpha at 80 times the continuum flux level, similar to the previous reported outbursts in 1998 (Hynes et al., 2002) and 2005 (Yan et al., 2007). Our spectroscopic observations ranging from 3800 - 8900 A (Mercator/HERMES, La Palma) from 09 - 15 October show a daily increase in the strength of nearly all emission lines with the notable exception of [NII] 5755.

Further multi-wavelength observations are strongly encouraged as the outburst closely resembles the spectacular outburst in 1998 over the complete wavelength range from gamma-ray to radio. At that epoch the X-ray flux reached a peak intensity of almost 2 crab, within a day after the onset (D. Smith et al., 1998). In 2005 the peak brightness reached V = 11.2 after which it rapidly declined in a few months to V = 11.8.

Now the highly disputed distance to CI Cam is settled by GAIA at 1.4 (+0.7 -0.4) kpc, we note that CI Cam is unlikely a supergiant. This confirms the earlier designation as B4 III-V[e] for the optical star with an accreting white dwarf companion as suggested by Barsukova et al. (2006). The likely scenario would be a thermonuclear runaway of accreted matter on the surface of the white dwarf, like in a nova outburst (Ishida et al., 2004).


http://www.astronomerstelegram.org/?read=9634


Spectra welcome !

François Teyssier

[Francois Teyssier]

A nice target

Lecture : http://iopscience.iop.org/article/10.1086/511181/pdf

CICam.PNG (27.95 KiB) Viewed 6050 times

François

[Paolo Berardi]

Hi François, thanks for the alert. For me an unusual profile. It seems that all emission lines are double-peaked (at first I thought they were broadened). With an higher resolving power you should see better.

Just finished a session with Lhires III and 1200 l/mm grating. About 20000 ADU counts for the h-alpha with 960s exp (C9.25, SXVR-H694):



In the 2d spectrum can also be discerned the doubled lines:



Paolo

[Francois Teyssier]

A great spectrum Paolo !

Looks to be the signature of a disk

In http://iopscience.iop.org/article/10.1086/511181/pdf


Miroshnichenko et al. (2002) obtained triple peaked Fe II emission lines in their high-resolution observations. Forbidden lines such as [Fe II], [N II], [O I], and [O III] were observed in the spectrum of CI Cam. The presence of these forbidden lines indicates that the circumstellar (CS) disk material is geometrically extended so that there is a large amount of low density gas (Lamers et al. 1998) in the outer regions of CI Cam

François
PS: Perhap's clear sky this night ...

[Peter Somogyi]

Hello,

Yesterday unexpectedly I also got some clear sky, but with the 150/mm + 35um low res (ISIS: R~420). Now looking at plenty of spikes at Paolo's spectrum, I can see maybe the low res choice was suboptimal. Finally got 1 x 10 min + 1 x 8 min + 1 x 10 minute exposures with H-alpha little bit overexposed (2x2 binning seems now also a mistake). Decided a shoot short exposure later, but suddenly clouds appeared. Used ref. star HD 27322 at the beginning (clouds prevented to shoot again at end).

cicam_20161016_pso.png (25.92 KiB) Viewed 5958 times

SNR should be good enough for the green part (3000 ADU bin 2x2), just the H-gamma blue end gets defocused as usual.

Peter

[Peter Somogyi]

Last night's result, this time with the 600/mm grating (300/1200 Newton + LHires):

CICam_Hbeta.png (48.05 KiB) Viewed 5882 times

(6 x 10 minute, mostly clear sky, R~1800)

CICam_Halpha.png (42.16 KiB) Viewed 5882 times

(3 x 10 minute, with cloud interrupts, R~2500)

CICam_heI5876.png (30.62 KiB) Viewed 5882 times

(1 x 10 minute, clouds fully closed then, R~2000)
Although SNR is not the best for this last one, EWs look still usable.

If my understanding from alert notice is right, the mentioned [NII] 5755 should be the tiny peak left to the big He I 5876.
Line identifications would be appreciated.

Cheers,
Peter