[vsnet-alert 14209] Summary of our new dwarf nova MisV1446 discovery.

[Seiichi Yoshida]

Dear colleagues,

* Note that this reports the follow-up information and summary of our
  new dwarf nova, posted on Jan. 9 [vsnet-alert 14080].

  MisV1446: Outburst of an X-ray Source
  http://www.aerith.net/misao/variable/MisV1446.html

On January 9, 2012, we the MISAO Project discovered a new dwarf nova,
outburst of an X-ray source, from the survey images taken by
Youichirou Nakashima.

This dwarf nova was discovered by Seiichi Yoshida (MISAO Project) in the
MISAO Project nova survey. It was picked up as one of the nova
candidates from Youichirou Nakashima (Okayama, Japan)'s unfiltered CCD
images on 2012 Jan. 5 by the PIXY System 2. It locates at R.A. 
07h41m12s.70, Decl. -09o45'55".9 (equinox J2000.0) and the brightness
was 14.1 mag.

This object was not found on the past images of the MISAO Project from
Jan. 15 to Dec. 24 in 2011 by Nakashima with a limiting magnitude of
14.6-15.6 mag.

Yoshida confirmed that it is not a known asteroid using the Minor Planet
Checker. Yoshida also confirmed that it is not an infrared object using
the 2MASS images.

The SIMBAD database shows an X-ray source 1RXS J074112.2-094529 exists
near by this position. So it seemed to be an outburst of this X-ray
source.

Immediately, Diego Rodriguez confirmed the outburst of this
object. It was 14.65-14.66 mag on Jan. 8.919 and 8.923 on his
unfiltered CCD images with LX200 25cm f/6.3 and ST8XME. Then we the
MISAO Project assigned a new variable star designation MisV1446 to
this star.

We have discovered another dwarf nova MisV1443 just one year ago, on 2011
Jan. 10.

  MisV1443: Discovery of Bright Dwarf Nova in Orion
  http://www.aerith.net/misao/variable/MisV1443.html

Hidetaka Sato observed multi-band photometry on Jan. 9, and confirmed
that this star is bluish. Here is the report published at the CBAT
Transient Objects Confirmation Page (TOCP). 

    2012 01 09.0644

    V-band mag = 14.74 +/- 0.04. R-band mag = 14.55 +/- 0.01, I-Band
    mag = 14.36 +/- 0.01 by Hidetaka Sato, Ota-ku, Tokyo,
    Japan. Position end figures 12s.72, 56".2 (USNO-A2.0), remotely
    using 0.43-m f/4.5 reflector + CCD (EV2 CCD47-10-1-109) at
    iTelescope Astrocamp Observatory, Nerpio, Spain
    (MPC-I89). Magnitudes were measured on each two images of 60
    seconds (V) or 30 seconds (R and I) of exposure under 17.5 V, 18.0
    R, 17.5 I of the limiting magnitude at 1.5 of airmass. The
    position was derived from two co-added images of R-band
    exposure. The standard stars were taken on Landolt SA98-666, 670,
    671 and 685 at 1.5 of airmass.

Luca Buzzi Federica Luppi observed this object on Jan. 10. Here is the
report published at the CBAT Transient Objects Confirmation Page
(TOCP). 

    2012 01 10.965

    This transient was observed by Luca Buzzi and Federica Luppi from
    Schiaparelli Observatory, Varese, Italy. In a single unfiltered 30
    seconds image, it has position end figures 12s.71, 56".0 and
    magnitude 14.8. A star is visible in DSS red and blue images at
    position end figures 12s.71, 56".2 and magnitude 17.4 R. Image
    posted at URL:
    http://www.astrogeo.va.it/pub/TOCP/TCP_J07411270-0945559.jpg

Taichi Kato, Kyoto University, commented that GSC 2.3.2 has a 19.1(Bj)
mag counterpart.  The object looks like a dwarf nova with a relatively
large outburst amplitude.

Taichi Kato and Tomohito Ohshima, VSNET, reported that observations
between Jan. 11 and 15 by Seiichiro Kiyota, Kiyoshi Kasai, William
Stein, Berto Monard, and Enrique de Miguel detected superhumps with a
period of 0.07786 (7) days, confirming the SU UMa-type nature of this
object. The amplitude of the superhumps was 0.2 mag, but became
temporalily very small (~0.05 mag) on Jan. 14. Further observations
by Berto Monard, William Stein, Josch Hambsch, Greg Bolt, Kiyoshi
Kasai and Tomohito Ohshima et al. at Kyoto University, showed this
dwarf nova started the rapid decline on Jan 15. Since the length for
which this object was at the plateau stage was 5 days, the true start
of outburst seems to have been a little earlier.

Diego Rodriguez reported that the dwarf nova faded down to 17.13
mag(CR), 17.50 mag(CV), on Jan. 17.93.

Best regards,

--
Seiichi Yoshida
comet at aerith.net
http://www.aerith.net/