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April 3, 1999

    New variable star MisV0001    

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.

  R.A.  17h52m26s.59
  Decl. -17o40'00".7  (2000.0)
  Mag.  14.1C-16.9C


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.

The past MISAO project announce mails are available at:


Seiichi Yoshida

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