Dramatic infrared variability of WISE J1810-3305: catching early dust
  ejection during the thermal pulse of an AGB star?
  We present the discovery of a source with broadband infrared photometric
characteristics similar to Sakurai's Object. WISE J180956.27-330500.2
(hereafter, J1810-3305) shows very red WISE colors, but a very blue 2MASS [K]
vs. WISE [W1 (3.4 micron)] color. It was not visible during the IRAS era, but
now has a 12 micron flux well above the IRAS point source catalog detection
limit. There are also indications of variability in historical optical
photographic plates, as well as in multi-epoch AKARI mid-infrared measurements.
The broadband infrared spectral energy distribution, post-IRAS brightening and
multiwavelength variability are all characteristics also shared by Sakurai's
Object - a post asymptotic giant branch (post-AGB) star which underwent a late
thermal pulse and recently ejected massive envelopes of dust that are currently
expanding and cooling. Optical progenitor colors suggest that J1810-3305 may
have been of late spectral class. Its dramatic infrared brightening, and the
detection of a late-type optical counterpart are consistent with a scenario in
which we have caught an extremely massive dust ejection event (in 1998 or
shortly before) during the thermal pulse of an AGB star, thus providing a
unique opportunity to observe stellar evolution in this phase. J1810-3305 is
the only source in the entire WISE preliminary data release with similar
infrared SED and variability, emphasizing the rarity of such sources.
Confirmation of its nature is of great importance.
