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Follow-up observations of ASASSN-16ne with SEDM

ATel #9786; Thomas Kupfer (Caltech), Adam Miller (Northwestern), Nadejda Blagorodnova, James D. Neill and Richard Walters (Caltech)
on 24 Nov 2016; 01:19 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Nadejda Blagorodnova (nblago@ast.cam.ac.uk)

Subjects: Optical, Cataclysmic Variable, Nova

ASASSN-16ne was announced as rapidly rising optical transient by ASAS-SN project (Shappee et al., 2014) on 2016 Nov. 11 via Transient Name Server as AT 2016iad.

Denisenko & Korotkiy (Atel #9759) reported follow-up observations and historical data. They found a magnitude of V=15.26 +/- 0.04 mag on 2016 Nov 14.513 UT. The object is not detected on the DSS images with a limiting magnitude of ~21mag, implying an outburst amplitude >6mag. Denisenko & Korotkiy detected the object with 18.9mag on 2002 Mar 23.34 UT in archival images and reported on non-detections 9 days prior and 13 days after the detection on 2002 Mar 23.

We have obtained follow-up observations with the Spectral Energy Distribution Machine (SEDM)(range 350-950nm, spectral resolution R~100) on Palomar 60-inch (P60) telescope. The spectrum, obtained on 2016 Nov 23.497 UT, shows hydrogen Balmer absorption lines, common for CVs in outburst. However, the existence of these lines excludes an AMCVn type nature for the system.

Additionally, images in u, g and r band were obtained on 2016 Nov 23.536, 2016 Nov 23.532 and 2016 Nov 23.528 respectively with the SEDM. We find:

u =15.1 +/- 0.4 mag, g = 15.6 +/- 0.2 mag and r =16.0 +/- 0.1 mag

Therefore, the object stayed for at least 9 days with a similar brightness.

The dominant hydrogen lines, the outburst amplitude >6mag and the outburst duration of at least 9 days suggests a Dwarf Nova of U Gem type or a super-outburst of SU UMa type. In both cases the outburst amplitude is on the upper limit. Follow-up observations are encouraged to resolve the origin of the outburst.