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AAVSO Special Notice #47: Increased Activity in P Cyg AAVSO HOME > publications > special notice

AAVSO Special Notice #47

Increased Activity in P Cyg
May 19, 2007

P Cyg (2014+37A) is the prototype of massive stars with
high mass outflow; it is characterized by blue-shifted
emission lines along with red-shifted absorption lines.
Surprisingly, we've never created a Variable Star
of the Season article for this neat star - I'll have
to make sure that happens soon.

Located at
20:17:47.20 +38:01:58.5 J2000
it is typically around V=4.8 (though its
outburst in AD1600 reached 3rd magnitude), and is the
nearest of the Luminous Blue Variable (or S Dor) class,
currently thought to be the progenitors to some types of
supernovae.  eta Car is another example.

P Cyg also has a weakly visible surrounding nebulae
of about 3arcmin diameter, and an inner nebulae about
20arcsec diameter.

Lamers and de Groot (1992, A&A 257, 153)
also indicate that P Cyg has been slowly increasing in
mean brightness over the past few centuries, at a rate
of about 0.15mag per century. Recently, P Cyg has also
been showing increased H-alpha activity, as observed by
Ernst Pollman, a German spectroscopist.

Since P Cyg is an ideal target for the AAVSO PEP observers,
I would like to ask them to give P Cyg high priority in their
monitoring activity over the current season.  You can find the
PEP chart on the web page, including the suggested comparison
and check star. There are no nearby comp stars for CCD observers,
but those with wide-field systems could also give this a
try.  This remains an interesting target for visual
observers as well; the increased activity could be a
precursor for an outburst.



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