[vsnet-alert 8852] New bright object in Oph: ASAS 173313-2421.1

[Grzegorz Pojmanski]

New bright object in Oph: ASAS 173313-2421.1

Grzegorz Pojmanski, Warsaw University Astronomical Observatory reports:

ASAS3V instrument of The All Sky Automated Survey (telephoto lens 200/2.8,
diameter 70mm + CCD + Johnsons V  filter, 3 minute exposures, pixel size
14.8 arcsec, rms astrometric accuracy - 4  arcsec)

has detected new (previously unobserved by ASAS) object
(nova?, dwarf nova?) at RA = 17h 33m 13s  DEC = -24d 21'.1

Since it was the first observation of this field in this season, we cannot
determine the rate of brightening in the past days; thus some other kind
of variability cannot be excluded.
 

Three USNO_B1 stars are located close to this position:
#          id|           RA|          DEC|    B1|    R1|    B2|    R2|    I2|
 0656-0476479 17:33:12.0547 -24:21:13.330   0.00  18.15   0.00  17.35  15.60 
 0656-0476499 17:33:12.8700 -24:21:09.400   0.00  18.38  19.54  17.11  14.74 
 0656-0476504 17:33:13.1093 -24:21:16.330   0.00  18.46   0.00  17.69  15.53 

This region of Milky Way is severely reddened and no stars are visible
in DSS image, but all USNO and several other objects are visible in 
2MASS images.


Observations:
    DATE      UT                       HJD      V
26/10/2005 00:17:54 (Oct 26.013) 2453669.5092 < 14   (invisible)
09/02/2006 09:20:23 (Feb 09.390) 2453775.8863 12.077 
10/02/2006 07:50:01 (Feb 10.327) 2453776.8236 12.037
10/02/2006 07:53:32 (Feb 10.329) 2453776.8261 11.942 
10/02/2006 07:57:08 (Feb 10.332) 2453776.8286 12.010 
10/02/2006 08:00:47 (Feb 10.334) 2453776.8311 12.004 
10/02/2006 08:04:19 (Feb 10.337) 2453776.8336 11.995 
10/02/2006 08:07:59 (Feb 10.339) 2453776.8361 11.972
10/02/2006 08:11:37 (Feb 10.342) 2453776.8386 12.066


Object is also clearly visible in the ASAS3I I-filter images 
taken on 08/02/2006 09:06:25 UT.

Several measurements between HJD 2452300 and 2453000 seem to be artifacts
(after inspection on the original frames).

Light curve and images can be found on
http://www.astrouw.edu.pl/cgi-asas/asas_disc/173313-2421.1,3775

Regards,
Grzegorz Pojmanski