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Two small high amplitude varialbes?

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Trygve Prestgard
Trygve Prestgard's picture
Two small high amplitude varialbes?

Hi all,

Having been serching around for some more for variables in DSS and SDSS, I noticed these two high amplitude varialbe(?) objects that I'm kind of skeptical about. 

Object 1 - 2MASSI J0127391+280553 (01 27 39.179 +28 05 53.67)

This high-proper motion, faint red star (a brown dwarf acc. to Kirkpatrick et al.) that, acc. to SDSS9, shines at red(mag)= +20.9 and green(mag) = +22.9. However, in a POSS-II Blue image from this area, the star suddenly appears at blue(mag)= +17.3 (magnitude from USNO-B1.0).

Looking around vizier a little more I wasn't able to find any other such brightening of this object. I wonder if this sudden "brightening" was more likely the result of an overlapping artefact in the POSS-II Blue image? Furthermore, it seems odd that a brown dwarf (or a red dwarf star) would brighten this much?

I saw however that the GSC2.3 and 2.2 had this object listed as mag +18.0 in the Bj band, but these are maybe values extracted from DSS images?

The object is located very close to the Andromeda XXII dwarf galaxy.

 

Object 2 - USNO-B1.0 1018-0100015 (06 27 58.106 +11 50 42.90)

In a POSS-II Blue image this object appears at +17.9 mag while in all the other images, the object appears  only around 19-20 mag (Blue and red images). If this is not caused by some artefact in the POSS-II Blue image, I wonder if it migh be a small dwarf nova candidate?

No SDSS imges are available for this area unfortunately.

 

Thanks for your help,

Best regards,

Trygve

 

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