MISAO Project

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    Rules on the Discoverers    

New variable stars of the MISAO Project are discovered by the following steps.

  1. Examine the newly offered images by the PIXY system 2 and measure the magnitude of stars.
  2. Search the magnitude of those stars measured in the past in the database.
  3. For each star, compare the past magnitude in the database and newly measured magnitude and select stars whose magnitude differ. In general, stars with over 0.5 mag difference are selected.
  4. Staff of the MISAO Project check all selected stars on the images and remove mis-measurements or errors.
  5. Taichi Kato, VSOLJ (Variable Star Observers' League in Japan), and John Greaves, the United Kingdom, kindly search the identifications with known variable stars and so on. Staff of the MISAO Project also search them. When identified with a known variable star, it will be rejected. The identification search contains not only the GCVS and NSV objects but also undesignated new variable stars just discovered recently.
  6. Staff of the MISAO Project check all selected stars on the images again, and report only the stars evidently variable as new variable stars.

In the MISAO Project, the discoverers of variable stars discovered in those steps are defined as follows.

  • Staff of the MISAO Project who judged a selected star as a real new variable star after checking the images.
  • Image contributor of the newly offered and examined images.
  • Image contributor of the most early examined image on which the magnitude of the selected star was significantly different from that on the newly offered image.

First of all, the person who judged it as a new variable star becomes one of the discoverers. And the image contributor of the newly offered images on which the new variable star was discovered also becomes one of the discoverers. Because a variable star is discovered when there is a difference between two images, both the image contributors of the new image and the compared past image become discoverers.

The discoverer is settled based on the offered and examined order, not the exposure date order. Therefore, offer of old images is also significant.

In general, there are several past images. If the magnitude of the selected star is not different significantly from the newly measured magnitude, the images are rejected. If there are some images with significant difference, the image contributor of the most early examined one becomes a discoverer. For example, the magnitude of a newly measured star as 14.5 mag, while examined on 1999 Apr. 1, is recorded on the images offered in the past as follows:

Image ContributorExamined DateMagnitude
A1999 Jan. 114.0
B1999 Feb. 113.6
C1999 Mar. 113.5

In this case, because the magnitude of A's image is not different significantly, it is rejected. On the other hand, the difference of C's image is larger than B's image. But the magnitude of B's image is also different significantly. So B, the contributor of the earlier examined image, becomes a discoverer.

In case that a star is not detected on the newly offered images and detected in the offered images in the past, the contributor of the new images becomes a discoverer preferentially, as same as mentioned above.

The discoverers settled in this definition are noted in the order mentioned above in the new variable star catalogues. In the papers like IBVS of new variable stars announcement, the names of discoverers are noted as image observers.

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