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    Complex Around a Mira Type Variable MisV1262    

February 24, 2007
Yoshida, S.; Ohkura, N.; Kadota

MisV1262, R.A. = 22h24m06s.65, Decl. = +54o45'33".4 (2000.0), is one of the new variable stars discovered by the MISAO Project.


It was announced on 2004 Mar. 18 as a possible semi-regular variable with an unfiltered magnitude range of 12.5 - 13.8 based on our observations between 2000 Aug. 29 and 2001 Oct. 13 by Nobuo Ohkura.

Further observations in 2003 September by Nobuo Ohkura revealed that the amplitude is much larger, with an unfiltered magnitude range of 12.5 - 14.5, and it is probably a Mira type.

Unexpectedly, V-band observations around the same time by Nobuo Ohkura also caught a 14.9 mag star at the position of MisV1262. It was almost constant at 14.9 mag between Oct. 25 and Nov. 4 in 2003, and between Oct. 15 and Nov. 1 in 2004.

Investigating DSS images and USNO-B1.0 catalog, I found there is a complex of three stars within 15 arcsec at the position of MisV1262.

(1) USNO-B1.0 1447-0404771 22h24m06s.1207 +54o45'25".570
17.150(B1) 15.600(R1) 17.650(B2) 16.490(R2)

(2) USNO-B1.0 1447-0404778 22h24m06s.5313 +54o45'32".900
16.880(B1) 17.540(B2)
    = USNO-B1.0 1447-0404781 22h24m06s.6493 +54o45'33".350
12.180(R1) 14.060(R2)

(3) USNO-B1.0 1447-0404786 22h24m07s.1247 +54o45'38".210
15.020(B1) 15.440(B2) 14.660(R2)

It is clear that star (2) is our variable star MisV1262 based on the DSS images and USNO-B1.0 color.

The DSS images and USNO-B1.0 color revealed that star (3) becomes brighter than star (2) in B-band, and probably in V-band. Therefore, a 14.9 mag star in our V-band images in 2003 and 2004 must be star (3), not MisV1262. MisV1262 must have been much fainter at that time.

The NSVS light curve also shows a rough variation of this star with a range of 12.8 - 14.1 mag. However, the NSVS data must be blending of the complex, and must not show the total variation.

DSS color image

RGB composite image from DSS I, R and Bj images.

The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166.

The DSS images are obtained at the Astronomical Image On-line Access Interface (http://dss.mtk.nao.ac.jp/).

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