[vsnet-alert 11860] Re: V407 Cyg outburst

[Luboš Brát]

Hi all,

we have monitored the symbiotic - mira variable V 407 Cyg during years 
2003 - 2005. The object showed classical mira - type pulsations with period 
~ 750 days. Our VRI data shows, that color indexes V-R is about 2.5 mag and 
R-I is the same value 2.5 mag during the mira cycle.
In guiescent, the V ranges from 12.1 - 14.3 mag, Rc = 9.2 - 12.2 mag, Ic = 
7.0 - 9.8 mag during mira pulsations.

The VRI light curve from MEDUZA database is here:
http://var2.astro.cz/EN/meduza/light-curves-ccd.php?star=V%20407%20Cyg&shv=Cyg

In this recent symbiotic outburst, the V-R is 1.26 mag and R-I is 1.37 mag 
(Hiroyuki Maehara report). So the object is bluer than in quiescent, what 
corresponds with our understanding of symbiotic outbursts.

With best regards
Lubos Brat
- Variable Star and Exoplanet Section
of Czech Astronomical Society
http://var.astro.cz



----- Original Message ----- 
From: "Taichi Kato" <tkato at kusastro.kyoto-u.ac.jp>
To: <variable_star_forum at yahoogroups.com>; 
<vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp>; <vsnet-alert at yahoogroups.com>; 
<vsnet-campaign-nova at ooruri.kusastro.kyoto-u.ac.jp>; 
<vsnet-campaign-symbio at ooruri.kusastro.kyoto-u.ac.jp>; 
<vsnet-outburst at ooruri.kusastro.kyoto-u.ac.jp>; 
<vsnet-outburst at yahoogroups.com>
Sent: Friday, March 12, 2010 2:00 AM
Subject: [vsnet-alert 11858] Re: V407 Cyg outburst


>>  V407 Cyg is undergoing a bright (V=7.9) outburst!
>> Follow-up observations are encouraged.
>
>   Indeed surprising!  Although I expected that the object would be
> bright in the visual, this redness is unexpected.
>
>   The object may be undergoing a nova outburst (highly reddened?)
> or may be undergoing a "red-nova" outburst resembling V838 Mon etc.
> Urgent spectroscopy is encouraged!
>
>   Could someone propose a Swift TOO observation?