[vsnet-alert 9557] Possible NSV 1485 outburst

Denis Denisenko denis at hea.iki.rssi.ru
Tue Sep 11 09:20:31 JST 2007

The poorly studied cataclysmic variable in Camelopardalis NSV 1485 
appears to be in outburst, as shown by observations with 1.5-m 
Russian-Turkish Telescope (RTT150).  The star has brightened by 1-1.5 
magnitude on the images taken between 02:20-02:40 UT on Sep. 10th, 2007 
as compared to the previous nights.

NSV 1485 was monitored with RTT150 from Aug. 26 to Sep. 07, with 2-3 
hours photometric runs obtained on 6 nights (Aug. 26, 29, 30, 31, Sep. 
01 and 02).  The short coverage (with the object rising above 30 deg 
elevation in the morning) and rather smooth lightcurve without eclipses 
did not allow to distinguish between two period aliases, namely 0.0717d 
and 0.0771d (14 and 13 revolutions per day, correspondingly).  But the 
period is surely below 2 hours.  Observations are highly encouraged from 
both Western (USA) and Eastern (Europe, Japan) longitudes.  I am not 
able to continue observing NSV 1485 any longer since my 17-night-long 
observing run at RTT150 is finishing tonight.

I will be publishing the article on this star based on my findings so 
far.  Please note that NSV 1485 is *incorrectly* identified in Simbad 
and in a recent paper by the Russian amateur astronomer Anton Khruslov 
(PZP, 5, 4, 2005).  The identification with USNO-A2.0 1575-01945880 
(R=14.7, B=15.2) is wrong!  The variable is a fainter blue star 
USNO-A2.0 1575-01945732 (R=16.7, B=15.9) 8.6" due West, according to 
RTT150 astrometry, or 7.4" in PA=250, according to USNO-A2.0.

NSV 1485 (SVS 958) was originally discovered by T.Meshkova on Moscow 
photographic plates in 1944 (Astron. Tsir. 26, p. 4) as a variable of 
unknown type with the range of 12.9-<14.5.  A.Khruslov has found 
outburst(s) in ROTSE data from 2000-2001 (NSVS object 519054).  Due to 
the proximity of U1575_01945880 and U1575_01945732, ROTSE with its 
angular resolution of about 14" has taken these two stars for one with 
the combined Red magnitude changing between 13.2-15.7.  A little 
investigation on my side has shown that the variable is incorrectly 
identified, and I have added NSV 1485 to the program of new CV 
monitoring.  Observations with RTT150 have shown I was right, and the 
fainter star is actually varying.

NSVS light curve 
<http://skydot.lanl.gov/nsvs/star.php?num=519054&mask=0> is showing two 
outbursts probably of the different peak brightness (R=14.0 at 
JD~2451436 and R=13.2 at JD~2451522).  Combined with the orbital period 
below 2 hours, this makes NSV 1485 a possible candidate to UGSU-type 
dwarf nova.  If the outburst is confirmed, please search for superhumps.

The color-combined 10'x9' finder chart with the correct position of 
cataclysmic variable marked with two white lines is available at 
<http://hea.iki.rssi.ru/~denis/NSV1485-comps.gif> (159 kB).  R and B 
magnitudes of several stars from USNO-A2.0 are shown.  Note that 
variability range given on the 2007/07/29 chart (13.2-16.7) is 
underestimated.  My observations here have shown the star varying 
between 17.2-17.8 at quiescence, and the maximum brightness is 
contaminated by the neighboring star.

J2000.0 coordinates of CV (also shown on the image) are:
RA = 04 12 36.89, Dec. = +69 29 06.4

Denis V. Denisenko
Space Research Institute (IKI)
Russian Academy of Sciences
Currently at the Turkish National Observatory (TUG)
5648282 (at) mail (dot) ru

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