[vsnet-alert 12119] Re: LkHA 188 G4 outburst (ATEL)

[Gianluca Masi]

Dear All,

a few nights ago I managed to confirm this strong outburst. You can find 
an image of mine here:

http://virtualtelescope.bellatrixobservatory.org/LkHA_188G4_20aug2010.jpg

I would like to ask if there is any photometry available for this field.

Thanks,
Gianluca


Taichi Kato ha scritto:
>    This object would be of high interest.  The relatively low reddening
> in this dark cloud would be also interesting.  The spetrum reported
> for LkHA 188 G4 was K7-M0 (em), at V=18.9.
> 
> Please use the designation LkHA188G4 in reporting VSNET format.
> 
> ===
> 
> ATEL #2801							     ATEL #2801
> 
> Title:		A possible new FUor star in NGC 7000
> Author:	E. Semkov, S. Peneva (Institute of Astronomy, Sofia, Bulgaria)
> Queries:	esemkov at astro.bas.bg
> Posted:	17 Aug 2010;  23:55  UT
> Subjects:	Optical, Variables
> 
> We report the discovery of a strong outburst in the region of NGC 7000/IC
> 5070. A source of the outburst seems to be a T Tauri star located in the
> dark clouds between North American and Pelican Nebulae. The first designation
> of this object LkHA 188 G4 is given by Cohen and Kuhi (1979). The star
> is a member of a small group of H alpha emission stars around LkHA 188.
> The object is included in the Catalog of emission-line stars of the Orion
> population (Herbig et al. 1988) with the designation HBC 722. According
> to SIMBAD Astronomical Database the coordinates of the star are:   <br
> />   (J2000) 20 58 17.03 +43 53 43.4   <br />   The results from our photometric
> observations indicate that for a period of about three months (from 13
> May 2010 to 16 August 2010) the star brightness increased by 3.3 mag. (R).
> At the same time the star has become considerably bluer. The V-R index
> decreased from 0.65 mag. (May) to 0.45 mag. (August). The photometric data
> from the period 6-16 August 2010 suggest that the star brightness rises
> continuously by approximately 0.04 mag. per day. Our photometric observations
> from 16 August 2010 give the following magnitudes:   <br />   R=13.33 and
> V=13.77   <br />   The magnitudes calibration of our data was carried out
> with respect to five stars from USNO-B1.0 Catalog.    <br />   Having in
> mind the rapid increase in brightness, we assume that the observed outburst
> is from FUor type. Such a rapid increase in brightness is observed in cases
> of FU Ori and V1057 Cyg. But an outburst from EXor type or an object similar
> to V1647 Ori are also possible. We encourage those observers interested
> in FUor and EXor variables to start a photometric and spectroscopic following
> of HBC 722. The multicolor photometric observations and high resolution
> spectroscopy are very important for the exact determination of the outburst
> type.     
> 
> ------------------------------------------------------------------------------
> Password Certification:  E. Semkov  (esemkov at astro.bas.bg)
> http://www.astronomerstelegram.org/?read=2801
> ==============================================================================
> 
>