----- Original Message -----
From: "Taichi Kato"
To: variable_star_forum; vsnet-alert; vsnet-alert; vsnet-campaign-be; vsnet-campaign
Sent: Saturday, May 19, 2007 3:50 AM
Subject: [vsnet-alert 9359] P Cyg activity

According to Ernst Pollmann, the line profiles of P Cyg
have shown violent variations (Halpha emission and of the
absorption component of He I 6678, from "be-stars").

Kenji Nakai-san also independently noted brightening
(vsnet-obs 58158). These observation may indicate a significant
mass-loss event.

Follow-up observations are encouraged.
YYYYMMDD(UT) mag observer
20070318.767 48 (Atsuko Takahashi)
20070320.812 48 (Yasunori Watanabe)
20070322.208 48 (Gobet Franck)
20070323.822 48 (Yasunori Watanabe)
20070325.769 48 (Atsuko Takahashi)
20070404.174 48 (Gobet Franck)
20070405.151 46 (Gobet Franck)
20070406.156 48 (Gobet Franck)
20070407.167 48 (Gobet Franck)
20070412.174 46 (Gobet Franck)
20070425.649 50 (Kenji Nakai)
20070502.651 48 (Kenji Nakai)
20070504.157 46 (Gobet Franck)
20070509.926 48 (Gobet Franck)
20070514.632 48 (Kenji Nakai)
20070517.572 45 (Kenji Nakai)

----- Original Message -----
From: "Dietmar Bannuscher"
To: <forum(==>)bav-astro.de>
Sent: Saturday, May 19, 2007 3:52 PM
Subject: BAV-Forum: [vsnet-alert 9359] P Cyg activity (fwd)

Hallo BAVer,

Ernst Pollmann entdeckte starke Veränderungen im Spektrum von P Cyg.
(H alpha Linie und andere).
Gleichzeitige Helligkeitsschätzungen sehen einen Anstieg von immerhin bisher
0.3 mag. Dies wird als Hinweis für einen großen Massenverlust gewertet.

Vielleicht jetzt doch die Gelegenheit diesen Stern zu beobachten und damit
auch eine Zusammenarbeit mit den Spektroskopikern zu beginnen.

Viele Grüße
Dietmar Bannuscher

----- Original Message -----
From: <aavso(==>)aavso.org>
To: <w_renz(==>)...>
Sent: Saturday, May 19, 2007 4:37 PM
Subject: AAVSO Special Notice #47: Increased Activity in P Cyg

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.

Arne

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Ich benötige unabhängige Beobachtung zur Bestätigung.

Visuelle Daten haben natürlich nicht die Genauigkeit, um so geringfügige Verände-
rungen (wie hier wahrscheinlich benötigt wird) ermitteln zu können.

Hallo Wolfgang!
Es ist eben die Frage, ob "geringfügige" V-Helligkeitsänderungen (bei der Ursachenforschung der Halpha-EW-Variationen in meinem Plot) in Betracht zu ziehen sind. Das AAVSO-Band der V-Helligkeiten wird zwar schnell mit großer Streuung der Schätzwerte der Einzelbeobachter abgetan, was jedoch nicht ausschließt, dass diese Variationen doch einen höheren Wahrheitsgehalt besitzen als allgemein angenommen. Deshalb bin ich dagegen, vorschnell gemittelte Streuungen als relevanter anzusehen. Immerhin beträgt das "AAVSO-Streuband" nahezu 1,5mag.

Wenn sich die Veränderungen auf die H-Emissionen beschränken sind V Band Daten
auch nicht unbedingt ideal. Da wären B Band (Hbeta und Hgamma) und Rc Band
(Halpha) Daten wahrscheinlich geeigneter und aufschlußreicher.