FF cam is the weirdest thing i had never observed.
Daily spectras are differents, intensities variation, shape, double or single peak, all configurations of the h alpha line for a Be star are possible.
4 differents observers are following this challenging star. Three echelle spectrographs (Eshell) and one long slit H alpha centered spectrograph (LhiresIII) with telescopes from 0.28m to 0.80m. 3 in Europe and 1 in US.
Summary of the H alpha profiles:
And some plots to understand the behavior of this star:
Dynagraph, heliocentric plot of the 2D spectra, H alpha at the center for every dates. Jan 6, at bottom, March 14 top. Telluric lines are straight absorption lines near H alpha, look at the absorption lines at right of H alpha who has a periodic radial velocity different from H alpha beahavior, best seen in the color dynagraph.
The quest continue
Update, comments from the PI: Anatoly Miroshnichenko, University of North Carolina, Greenboro USA
March, 22: "The FF Cam data do look interesting. I'm wondering what are the
average wavelengths of those three absorption lines that have a
different period from that of the Halpha line? There are not many
photospheric lines expected between Halpha and 6615 A. Some examples
are CII lines at 6577 and 6582 A for early B-type stars, but mostly
the lines in that region are telluric."
March 23: "Indeed, some absorption lines are present. They may belong to a cool
star, but in this case you can also find them in other echelle orders.
The carbon lines (6577 and 6582 A) I was talking about belong to the
photosphere of an early-B type star, not to a carbon WD. There are no
lines at these positions in your spectra.
The 8-day period is very short orbital period of a binary. If this is
true, then the distance between the stars of the binary is very small
and the Be disk should be small. This may explain the fast variations
of the H-alpha line profile. The material gets out of the star and
quickly fills the disk, but the material supply is unstable and the
material spatial distribution changes quickly leading to changes of
the line profile. If the disk is small, the H-alpha emission will
never be strong. This is what is observed."