[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
MisV cross identifications
MISAO Project Announce Mail (July 16, 2001)
Hello. I am Seiichi Yoshida working on the MISAO project.
The number of new variable stars discovered in the course of the MISAO
Project reached to 1119 on May 30. But most of them have observations
at only a several nights, so their type is uncertain.
There may be some valuable objects among them, like novae or some
cataclysmic variables. In order to confirm that, we have to look up
past images like the DSS (Digitized Sky Survey). But it takes some
time to do it for all new variable stars.
We have been referring to two star catalogs, the GSC 1.1 and the
USNO-A2.0, and an infrared catalog, the IRAS Point Source Catalogue,
and picking up counterpart data of every MisV star. If there is data
in those catalogs, we can say the star is not a nova or cataclysmic
However, many MisV stars are not recorded in any of those catalogs,
probably because the MISAO Project new variable stars are very faint
in common. So we could not select small number of remarkable
candidates of novae or cataclysmic variables among many new variable
Recently, many new star catalogs and infrared catalogs are released.
Then John Greaves, the United Kingdom, and Seiichi Yoshida researched
those new catalogs to find the counterpart of every MisV star.
We worked on the following catalogs.
* 2MASS (The Two Micron All Sky Survey)
The infrared catalog all over the sky. Although data of only half of
the whole sky is released now, all data will be released in 2002. It
contains about 300 million data and covers very faint stars. The
position is as accurate as, or more accurate than, the general star
catalogs. We can also judge whether a star is a red variable or not
based on the J-band and K-band magnitude. The data can be retrieved
at the following site.
* UCAC1 (USNO CCD Astrograph Catalog)
The accurate astrometric catalog covering down to 16 mag. The UCAC2
will be released in 2002, and the data all over the whole sky will
be released in 2003. The data can be retrieved at the following
* GSC 2.2 (Guide Star Catalog II)
The next version of the well-known star catalog, GSC 1.1. Although
the GSC 1.1 covers down to 13-16 mag, the GSC 2.2 contains stars
down to 19 mag. The magnitude in two bands are recorded. The GSC 2.2
contains about 435 million data. The final version, GSC 2.3, will
be released in 2002. The data can be retrieved at the GSC 2.2 home
* MSX5C (Midcourse Space Experiment Point Source Catalog)
The infrared catalog along the galaxy plane. It contains very faint
stars. It is useful especially where the 2MASS data is not yet
released. The data can be retrieved at the following site.
The recent new catalogs contain many faint stars. Especially, most of
the red variable stars, Mira-type or semi-regular type, which appears
very bright on CCD images, are recorded in the 2MASS catalog.
After this research, only 27 objects among 1119 are selected, which
has no counterpart data in any catalogs.
John Greaves and Seiichi Yoshida checked the past images for the rest
27 stars using the following web services, and revealed they are not
novae or cataclysmic variables.
USNO Flagstaff Station Integrated Image and Catalogue Archive Service
Astronomical Image On-line Access Interface
The identification results of this research are merged in the MisV
catalog available at the MISAO Project home page.
In the IBVS 5135 issued on July 9:
The 76th Name-List of Variable Stars
the permanent designations are assigned to 179 MisV new variable
stars. For example, MisV0001 should be called V4652 Sgr, MisV0002
should be called V523 Aur after this. These GCVS designations are also
merged in the MisV catalog available at the MISAO Project home page.
The past MISAO project announce mails are available at: