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Spectro, Astero et Hélio Blog
2 février 2012

FF cam, January behavior of the H alpha line

I've started a spectral monitoring of one my favorite star, FF cam.

I discovered this star in 2009 by a routine survey of Be stars. Considering the Bess program, this star was observed only once par year before. I was surprised in 2009 in two consecutives nights, while redoing spectra due to bad SNR, to see how much the h alpha profile has changed. I did some others spectra in 2009 showing a great activities in H alpha and let it down for a while. At this time i was using a LhiresIII spectrograph, centered on H alpha with a power of resolution of 15000.

In the beginning of January i restarted a monitoring with my eshell setup, covering the whole optical window. I've took nearly one échelle spectra every night from Jan, 6th trying to described completely the behavior of this star.

Associated with a soft X source, this star is certainly an unknown Be/X binaries with orbit phase dependent H alpha profile. These binaries are composed of B type dwarf star and a compact object, white dwarf neutron star or black holes orbiting close from each other. Nearly 4 weeks of daily observations cannot let find any period in the equivalent widht (strenght of the line) or profile in H alpha. More observations are needed, as Be/X binaries may have period from tens of days to tens of weeks.

So first results, sent to Anatoly Miroshnichenko University of North carolina, are presenting here, only in H alpha for the moment. All échelle spectra are available in Bess database. Mean SNR is around 70, power of resolution is 10000, dispersion 0.1A.

I don't know apart Sheliak, bet Lyr, such spectra activity. You may look to FF cam in arasbeam to have a quick look the the H alpha line

Enjoy observing this star as often as you can, it is circumpolar. It belongs to the realm of the rare aftermath stellar binaries among the Be star.

multiplot_6540_6585FFcam-2012_Janew_courbe (2)

Update: Comments from Anatoly Miroshnichenko (University of Greenborough, North Carolina):

"I looked at the information on FF Cam. It has a near-IR excess which
is partly due to the interstellar extinction and partly to the
circumstellar gas radiation. What is more interesting is that it is
associated with an X-ray source. This may indicate that it is an
Be/X-ray binary system. What is needed is a UBV photometry and a
measurement of the strengths of the diffuse interstellar bands at
5780, 5797, and/or 6614 A. I think I see them in your eshelle spectra
(at least 5780). You (or I) can sum up all your data for the spectral
order that contains this band to increase the signal-to-noise ratio.
This band equivalent width correlates with the interstellar extinction
(Av). In combination with the photometry and some other spectral
features (for example, the line intensity ratio of HeI 4471 and Mg II
4481), this will get us the spectral type and an estimate of the
circumstellar reddening. Your spectra already show that the Be star
has a mid-B spectral type (perhaps, B4-B5 or so), because the Mg II
line is stronger than the He I line. I can look at these issues
closely and ask colleagues for an optical photometry.

Cheers,

Anatoly"

Another high mass X binaries in Cameolopardis is CT cam who is a B[e], belonging to FS cma group. It is known to have a black hole around a B supergiant, with transient X ray ouburst. May FF cam belonging to the FS cma group too as it has a IR excess ?


Update: Webpage on H alpha spectra of FF cam http://www.astrosurf.com/garrel/FFcam.html



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