[vsnet-outburst 15968] MASTER OT J040552.59+274716.7: likely WZ Sge-type dwarf nova (ATEL)

[Taichi Kato]

MASTER OT J040552.59+274716.7: likely WZ Sge-type dwarf nova (ATEL)

   The presence of He II emission suggest a WZ Sge-type dwarf nova
with a moderate inclination.  Observations are encouraged!

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ATEL #5381							     ATEL #5381

Title:	Spectroscopy of MASTER OT J040552.59+274716.7 in Taurus
Author:	R. M. Wagner (Ohio State), C. E. Woodward (Minnesota), and
		S. G. Starrfield (Arizona State)
Queries:	mwagner at lbto.org
Posted:	9 Sep 2013; 16:53 UT
Subjects:Optical, Cataclysmic Variable, Nova, Transient

We observed the optical transient designated MASTER OT J040552.59+274716.7
reported by Denisenko et al. (ATEL #5369) on 2013-09-06.4090 UT with the
2.4 m Hiltner telescope on Kitt Peak, Arizona.  We confirm the presence
of a bright transient at the position reported by Denisenko et al. Furthermore,
we obtained several spectra of the transient using the OSU CCD Spectrograph
(CCDS; range: 366-730 nm; resolution: 0.9 nm).  The average spectrum exhibits
emission lines of the Balmer series of hydrogen; He I 706.5, 667.8, 587.5
nm; He II 468.6 nm; and perhaps N III 464.0 nm.  The equivalent width of
H-alpha emission was 1.60 nm and with a FWHM of 1.32 nm (corrected for
instrumental resolution).  In addition, weaker H-beta and several of the
higher order Balmer emission lines are superposed on broad (full-width
of 6.2 nm at H-beta) absorption troughs.  The spectrum is characteristic
of a dwarf nova near maximum light.  The appearance of the spectrum and
outburst amplitude of at least 7.5 mag reported by Denisenko et al. suggests
that the transient is a member of the WZ Sge subclass.  Further time-resolved
photometric observations are encouraged.