Poster abstract details
Nebula around R Coranae Borealis
Abstract
The star R Coranae Borealis shows forbidden lines of [O\,{\sc ii}],
[N\,{\sc ii}] and [S\,{\sc ii}] during the deep minimum when the star is fainter
by about 8 to 9 magnitudes from normal brightness, suggesting presence
of nebular material around it. We present low and high spectral
resolution observations of these lines during the ongoing deep
minimum of R CrB, which started in July 2007. These emission lines
show double peaks with a seperation of about $100$ km s$^{-1}$ . The line
ratios of [S\,{\sc ii}] and [O\,{\sc ii}] suggest electron density of about
100 cm$^{-3}$. we discuss the physical conditions and possible origins
of this low density gas. These forbidden lines have also been
seen in other RCB stars during their deep light minima and thus
a general characteristic of these stars which might have some
relevance to their origins.
[N\,{\sc ii}] and [S\,{\sc ii}] during the deep minimum when the star is fainter
by about 8 to 9 magnitudes from normal brightness, suggesting presence
of nebular material around it. We present low and high spectral
resolution observations of these lines during the ongoing deep
minimum of R CrB, which started in July 2007. These emission lines
show double peaks with a seperation of about $100$ km s$^{-1}$ . The line
ratios of [S\,{\sc ii}] and [O\,{\sc ii}] suggest electron density of about
100 cm$^{-3}$. we discuss the physical conditions and possible origins
of this low density gas. These forbidden lines have also been
seen in other RCB stars during their deep light minima and thus
a general characteristic of these stars which might have some
relevance to their origins.