Confirmation of the FU Orionis Type Outburst of 2MASS J06593158-0405277
ATel #6797; Lynne Hillenbrand (Caltech)
on 9 Dec 2014; 21:20 UT
Credential Certification: Lynne Hillenbrand (lah@astro.caltech.edu)
Subjects: Optical, Variables, Young Stellar Object
From a high dispersion spectrum obtained with Keck/HIRES on 9 December 2014, UT,
we confirm the FU Orionis interpretation of the optical brightening and
low resolution spectral signatures reported for 2MASS J06593158-0405277
by Maehara and Fujii in ATel 6770. At R=72,000 the absorption line spectrum
is an excellent match to that of an early F giant or supergiant.
The source has a classical P-Cygni type profile at Halpha
with no other permitted or forbidden line emission over the spectral range
4800-9200 Angstrom. There is broad blue-asymmetric absorption at Hbeta
as well as in the upper Paschen lines H11 and H12 that is also mimicked in the
combined Paschen plus CaII triplet lines. Other evidence for outflow occurs
in the MgIb triplet, NaD doublet, and BaII 6497 blend.
Importantly, the source has LiI 6707 absorption, a standard signature of youth.
Comparing 2MASS J06593158-0405277 in outburst
to the small number of other known members of the FU Ori class,
the symmetric lines in the early type low gravity absorption spectrum have
line widths comparable to those of V1057 Cyg and PTF 10qpf while the lines
with outflow signatures most resemble FU Ori itself.
The object was fairly bright even before its recent brightening
in many historical optical (e.g. DSS1/2), and near-infrared (e.g. 2MASS, UKIDSS)
images, and is incredibly bright at all four WISE bands, indicating significant
dust emission. It is, however, previously unstudied being located somewhat
north of the known recent star formation towards the Canis Majoris region.
We encourage continued monitoring of the source as it evolves over the
coming months.
supporting figures are available at the url provided
