The only spectra of V831 Cas currently in the ARAS BeAm database dates from
December 1996, so an update is overdue. Three low resolution
spectra were measured on 20th,22nd and 24th September 2008 using the
Star Analyser grating. While not showing the detailed line profile, it should be
possible to estimate if the strength of the H
alpha emission line has changed significantly.
The Star Analyser spectra were
reduced in the usual way and finally normalised using a fit to the
continuum. The 1996 spectrum from the OHP ELODIE database was
normalised in the same way and gaussian filtered to match the Star Analyser
resolution for comparison.
The 1996 filtered ELODIE spectrum
suggests that the H alpha emission should be clearly visible, peaking at
about 12% above the continuum in a Star Analyser spectrum provided a
sufficiently low signal/noise ratio could be achieved.
Three spectra
of successively increasing total exposure were taken on different nights.
The spectrum on 24th September taken under improved sky conditions
clearly shows the H alpha emission peaking approximately 7% above the continuum.
The measured level is lower than that measured in 1996 but the difference
may not be statistically significant.
A high resolution plot of
the H alpha region from the 1996 spectrum in the ELODIE Archive
