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An OH/IR makes a (faint) appearance?

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Matthew Templeton
An OH/IR makes a (faint) appearance?

This morning, the MASTER transient group published ATel #4560 announcing optical detection of a source coincident with the OH maser OH 63.3 -10.2.  This is a bright infrared source, but is (mostly) invisible in the optical.  Most (all?) of the OH/IR stars are pulsating like Mira stars, but have so much extinction from circumstellar dust they're invisible.  This one has put in a brief appearance for MASTER, getting caught at an unfiltered magnitude of 17.3 on 2012 November 6.5524 (2456238.0524).  According to Podvorotny et al., the object was detected on a Palomar red plate on 1992 August 31, but not on 1990 September 15.

Coordinates for the MASTER OT are 20 28 57.00, +21 15 33.2.  Coordinates for the 2MASS source known to be associated with the maser are 20 28 57.10, +21 15 37.0.  They are almost certainly the same source.

This will be a target for large-aperture telescopes, and will be very (very, very) red.  I've submitted it to VSX now, and I'll post a name once it's been approved and assigned an AUID.

Matthew Templeton
This star is now in

This star is now in VSX.

The name to use is "MASTER OT J202857.00+211533.2".  It is faint, so it might be tempting to go unfiltered, but filtered observations (as in Ic or Rc) would be far more useful.  This object's period and behavior is almost totally unknown, so a patient observer willing to make occasional observations of this field (going down to 18 or fainter) over the coming weeks and months would be doing something new.

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