[vsnet 1795] New variable star MisV0001

[Seiichi Yoshida <seiichi@muraoka.info.waseda.ac.jp>]

MISAO Project Announce Mail (Apr. 3, 1999)

Hello. I am Seiichi Yoshida working on the MISAO project.

The first new variable star MisV0001 was discovered in the MISAO
Project.

MisV0001 
  R.A.  17h52m26s.6
  Decl. -17o40'00"  (2000.0)
  Mag.  14.1C-16.9C

  http://www.info.waseda.ac.jp/muraoka/members/seiichi/misao/data/MisV/MisV0001.gif

This object was automatically discovered by the PIXY system from the
0.18-m reflector images of V4334 Sgr (Sakurai's object, cf. IAUC 6718)
taken on Mar. 22 by KenIchi Kadota, Ageo City, Saitama, Japan. 

The images were examined following the steps mentioned in the document 
at the MISAO Project Home Page, "PIXY system" - "Second Step" - "New
Object Survey". The PIXY system detected stars from the Mar. 22
images, then searched the database and found that the images of V4334
Sgr taken on Feb. 12 by KenIchi Kadota contain the same area. Because 
this 15.0-mag star detected from Mar. 22 images could not detected
from the Feb. 12 images (detected limiting magnitude is 16.4 mag), the 
system output this object as a new object. Actually, this object was
also found on the Feb. 12 images as 16.9 mag.

No bright star is at this position on the DSS2 image. Taichi Kato,
Kyoto University, reported there was only a faint object, fainter than 
16 mag (V mag), at this position on the images taken in 1996 March at
Ouda Observatory.

In the MISAO Project Identification database, there are no known
variable stars within 5 arcmin around this object. No data is recorded 
in the GSC. In the USNO-A1.0 catalog, there are two candidates but it
is not sure they are real counterparts of this new variable star.

USNO0675.14627465  17 52 26.686  -17 40 09.36  17.2R  19.1B      9.0"
USNO0675.14627525  17 52 26.751  -17 40 04.39  19.3R  19.8B      4.4"

The magnitude of this object are as follows. All images are taken by
KenIchi Kadota.

1999 Feb 12.83565  16.9C
1999 Feb 12.83852  16.9C
1999 Mar 22.79385  14.9C
1999 Mar 22.79594  15.1C
1999 Mar 31.75648  14.1C
1999 Mar 31.76264  14.1C
1999 Mar 31.76438  14.2C
1999 Mar 31.78179  14.9CIR
1999 Mar 31.78299  14.8CIR
1999 Mar 31.78541  14.9CIR
1999 Mar 31.79027  14.1R
1999 Mar 31.79293  14.0R
1999 Mar 31.79547  14.0R

  C:   CCD (no filter)
  CIR: IR-block filter + CCD
  R:   R60 filter + CCD

Further observations by KenIchi on Mar. 31 show that this star
brightened about 1 mag since Mar. 22. It is still brightening.
We could not find hitherto any observations showing this variable star 
had been brightened before 1999 February. Please check your past
images if you have.

This object is only 110 arcsec from V4334 Sgr. And it was discovered
from the images taken by KenIchi Kadota in purpose of observation of
V4334 Sgr. If he had only measured the magnitude of V4334 Sgr and done
nothing else, this new variable star would not have been discovered. 
This fact shows that any images for any purpose have possibility from
which some astronomical important information will be obtained if they 
are examined properly. New objects may be in your own images of
a comet, a supernova, clusters or nebula, etc. The goal of MISAO
Project is to dig out more new objects and more important data by
examining more images and referring one another.

P.S.
The past MISAO project announce mails are available at:
  http://www.info.waseda.ac.jp/muraoka/members/seiichi/misao/

--
Seiichi Yoshida
seiichi@muraoka.info.waseda.ac.jp
http://www.info.waseda.ac.jp/muraoka/members/seiichi/index.html

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