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[vsnet-chat 2310] Overlap of variable star survey



MISAO Project Announce Mail (September 21, 1999)

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

On September 21, 1999, the number of new variable stars discovered in
the course of the MISAO Project (MisV objects) reached to 472. Since
July 22 when the discovery of the 100th star MisV0100 was announced,
the number is increasing about 6 stars a day.

All of the new variable stars were discovered on the CCD images taken
by KenIchi Kadota, Ageo Survey Team. The Ageo Survey Team has been
searching mainly in the summer Milky Way. Therefore, most of the new
variable stars are in the summer Milky Way. The chart below shows the
new variable stars plotted on the celestial globe. The horizontal axis 
is right ascension in degree, the vertical axis is declination.

Decl.
    +-+--------+---------+--------+---------+--------+---------+--------+
 80 +++        +         +        +         +        +         +       ++
    |                                                                   |
 60 ++                                                                 ++
    |    **                                                             |
    |     * ** **                                                       |
 40 ++    * ** *                                   *                   ++
    |       ** *  *                                                     |
 20 ++         *  *                                                    ++
    |          *  ** *                                                  |
  0 ++............****..*..............................................++
    |             ** ** *                                               |
    |             ** *  *                                               |
-20 ++            *  *  *                                              ++
    |               **  *                                               |
-40 ++                                                                 ++
    |                                                                   |
-60 ++                                                                 ++
    |                                                                   |
    |                                                                   |
-80 +++        +         +        +         +        +         +       ++
    +-+--------+---------+--------+---------+--------+---------+--------+
     350      300       250      200       150      100       50        0 R.A.

Not only the MISAO Project, but there are some other variable star
survey projects now and many variable stars have been discovered.
Now that the survey area of the Ageo Survey Team is getting wider, 
some variable stars found in the MISAO Project happen to have been
already discovered by the other projects.

On the images taken by KenIchi Kadota between February and July in
1999, an unknown variable star from 10.8 mag to 12.0 mag was found at
R.A. 19h02m25s.63, Decl. -00o30'14".5 (2000.0). No variable star is
recorded at this position in the GCVS (General Catalog of Variable
Stars) 4th edition and the NSV (New Catalogue of Suspected Variable
Stars) catalogs. So we announced this object as a new variable star
MisV0130. However, Taichi Kato pointed out that this was already
discovered by the FASTT (Flagstaff Astrometric Scanning Transit
Telescope) project and published as HS1332 (FASTT1332).

This is the first case that a variable star found in the MISAO Project 
has been already discovered by the other project working on right now.
In order to be avoid confusion, we will cancel the number MisV0130 for 
this object. Therefore, only the MisV0130 is not a new object of the
MISAO Project among 472 MisV objects.

The FASTT project found 1602 variable stars using the FASTT telescope
at the U.S. Naval Observatory in the SDSS calibration fields
(including some known variable stars, not new ones). After that, we
added the FASTT stars into the MISAO Project database, so we will
never announce them as new objects by mistake. Actually, we also
detected the variability of HS1330 (FASTT1330), HS1463 (FASTT1463),
HS1466 (FASTT1466), but we do not announce them as new variable stars.

By the way, there must be known variable stars V886 Aql and VX Aql
near by HS1463 (FASTT1463) and HS1466 (FASTT1466) respectively. 
However, no other variable stars are found around these FASTT objects
on the Ageo Survey Team images. Therefore, we judged HS1463
(FASTT1463) and V886 Aql are the same object, HS1466 (FASTT1466) and
VX Aql are the same object.

To return to the subject, on the images taken by KenIchi Kadota
between April and August in 1999, another unknown variable star from
12.9 to 14.7 mag was found at R.A. 17h59m41s.66, Decl. -00o35'31".0
(2000.0). No variable star is recorded at this position in the GCVS
and NSV catalogs. However, Taichi Kato pointed out that this was
already discovered by the TASS (The Amateur Sky Survey) project and
published as TASS J175944.6-003558. Therefore, we did not announce it
as a new object, either.

The TASS project is a collaboration of amateur astronomers in the
world and 50 new variable stars have been discovered. We also added
these stars to the MISAO Project database.

All of the TASS new variable stars are around the equator, the
declination is between -2.4 deg and +1.5 deg. Many of the FASTT new
variable stars are also around the equator. But in the MISAO Project,
many new variable stars, not discovered by these projects, were
discovered even around the equator. Actually, between +/- 2 deg around 
the equator, we discovered 18 new variable stars such as MisV0009.

In the OGLE (Optical Gravitational Lensing Experiment) project, 58 new 
long-period variable stars were discovered, and 56 of them are in the
7x9 deg area around R.A. 18h, Decl. -30 deg. In fact, it is also the
area where the Ageo Survey Team searched most enthusiastically. The
number of MisV new variable stars in this area is 86, about 18% of
all. However, no variable star discovered in the MISAO Project
happened to have been discovered already by the OGLE project.

In addition, Japanese amateur astronomers Kesao Takamizawa and Katsumi
Haseda have discovered 515 and 32 new variable stars respectively.
However, no variable star discovered in the MISAO Project happened to
have been discovered already by them.

As a conclusion, many variable stars must be remained unknown even in
the area where some projects have searched in past. There are many
areas not yet searched all over the celestial globe, so enormous
variable stars must be remained unknown.

The lists of new variable stars discovered by the projects introduced
here are available at "Reference Catalogs" in the MISAO Project Home Page:

http://vsnet.info.waseda.ac.jp/muraoka/members/seiichi/misao/doc/reference.html

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

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

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