ASAS 102522-1542.4 -
Light curve analysis
I was able to confirm the new
dwarf nova on 2006, Jan 27.986 UT using a 0.35-m
f/6.3 telescope and ST-7XME CCD camera, and carried
out time-series photometry that same evening.
ASAS 102522-1542.4 was discovered by ASAS3V (Grzegorz
Pojmanski, Warsaw University Astronomical
Observatory) at RA = 10h 25m 22s DEC = -15d
42'.4 (J2000), on 2006, Jan 26.245 UT at V=12.22.
Initial outburst stage - orbital humps
The initial outburst stage of this object has
been very well covered by CBA observations from Tom
Krajci, Lew Cook and myself. We collected 3
observation sets, with a total of 1236 observations,
all characterised by double-peaked "early
superhumps" (or orbital humps). The duration of
this stage must have been pretty short : the
discovery of ASAS 102522 was made on Jan 26.2 UT (on
Jan 25.2 UT, the variable was still below ASAS'
detection limit), and early superhumps lasted till
Jan 28.5 UT. An analysis of this initial part of the
light curve yields early superhumps with a period
Porb = 0.0615 +/- 0.0010 d, and with an
amplitude of 0.04 mag (ANOVA method, Peranso).
ASAS 102522-1542.4 combined light
curve (zero-averaged, detrended) during initial
stage. Observations from Tom Krajci (black), Lew
Cook (red) and Tonny Vanmunster (blue).
ANOVA period analysis
yielding an orbital period of 0.0615d
Phase diagram showing
double-peaked early superhumps, by folding
all observations over a period of 0.0615d, then
averaged per 10 obs.
Main outburst stage - regular superhumps
Starting Jan 29.0 UT, ASAS 102522 went into a
different outburst stage, characterised by the
appearance of regular (full) superhumps. We
announced the detection of superhumps, establishing
the SU UMa dwarf nova nature, in an email
message of Jan 29th (Tonny Vanmunster, CVnet-outburst).
So far, we have collected 5 observation sets (Tom
Krajci, Pierre de Ponthiere, myself), with a total
of 2220 observations, covering this stage. The
resulting light curve clearly shows how superhumps
have grown from an amplitude of less than 0.1 mag
(Jan 29.0 UT) to over 0.25 mag (Jan 30.5 UT). Using
the ANOVA method, we find a superhump period
Psh = 0.0637 +/- 0.0002 d.
The superhump period excess of ASAS 102522 thus
becomes : (Psh - Porb) / Porb = 3.58%, a value that
is very well in line with expectations for a system
with an orbital period of about 1.5 hrs.
ASAS 102522-1542.4 combined
light curve (zero-averaged, detrended) during
stage. Observations from Tom Krajci (black), Pierre
de Ponthiere (olive) and Tonny Vanmunster (blue).
superhump period of 0.0637d
ANOVA period analysis yielding
Superhump phase diagram by
folding the observations over a period of 0.0637 d