backOGLE-2011-BLG-1444 - Is it a Symbiotic Nova?
The discovery of a rapidly brightening object at (RA, DEC) =
(17:50:19.27, -33:39:07.3) was announced
by Beamin et
al. (2013) based on VVV survey data. The object lies in the
field observed by
the OGLE-IV survey and was
announced on 2011 Sep 26 (JD = 2455830.5) as a candidate microlensing
event OGLE-2011-BLG-1444 on the OGLE Early Warning
System webpage.
The light curve of the object in 2011 observing season shows a rapid
brightening (0.14 mag/day) since Sep 19 till the end of a season
(i.e., Oct 27). During this time the brightness changed from
19.5 mag to 14.1 mag in I-band. The observations
returned on 2012 Feb 12. The object brightness was 11.2 mag
and the photometry should be treated with caution as the object is
close to the CCD saturation limit. Since then it varies between
11.58 mag and 10.24 mag in the I-band. The
semi-periodic behavior can be seen with light maxima separated by
around 120 d. Since the outburst 41 V-band measurements
were obtained. Only one V-band epoch was collected during the
outburst in 2011. No significant color variations are seen
and (V-I) = 1.5 mag. The reddening for bulge stars in this
direction is E(V-I) = 1.25 mag. The object was also monitored
during the OGLE-III project between 2001 and 2009. These data do not
reveal any significant periodicity or mean brightness variations.
However, the OGLE-IV pre-outburst photometry reveals some
semi-periodic variability with timescales of tens of days.
The very long and bright maximum phase suggests that
OGLE-2011-BLG-1444 is not a classical nova. Beamin et al.
(2013) proposed that the object is a nova-like star based on a
spectrum. OGLE light curve does not confirm this. Instead, we
suspect OGLE-2011-BLG-1444 may be a member of a small group called
symbiotic novae, which show long optical maximum.
Full OGLE light curve is presented below.
Whole OGLE I-band light curve for OGLE-2011-BLG-1444.
2010 and 2011 V- and I-band photometry of OGLE-2011-BLG-1444.
2012 and 2013 V- and I-band photometry of OGLE-2011-BLG-1444.
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