ATLAS and Liverpool Telescope observations of the type II SN 2018hna
ATel #12258; S. J. Prentice, S. J. Smartt, K. Maguire, K. W. Smith, A. McCormack (Queen's University Belfast), L. Denneau, H. Flewelling, A. Heinze, J. Tonry, H. Weiland (IfA, University of Hawaii), B. Stalder (LSST) A. Rest (STScI), P. Clark, M. Fulton, O. McBrien, M. Magee, D. O'Neill, D. R. Young (Queen's University Belfast), D. E. Wright (University of Minnesota)
on 3 Dec 2018; 10:53 UT
Credential Certification: Simon Prentice (s.prentice@qub.ac.uk)
Subjects: Optical, Supernovae
Referred to by ATel #: 12897
The type II SN 2018hna (TNS #30529) was discovered on 2018-10-22 21:17:49 (UTC) by K. Itagaki.
Photometric observations were made beginning 35 days later on 2018-11-16 15:36:00 (UTC) by the ATLAS twin 0.5m telescope system on Haleakala and Mauna Loa (Tonry et al. 2018, PASP, 13, 064505), and have shown that the light curve is still rising. The latest ATLAS o-band measurement, from 2018-11-28 15:50:24 (UTC), is ~14.8 mag (absolute magnitude ~ -15 mag).
The long rise is ongoing, and can be seen in the public Zwicky Transient Facility (ZTF) light curve on the Lasair broker (https://lasair.roe.ac.uk/object/ZTF18acbwaxk).
We also observed SN 2018hna on 2018-11-30 05:56:21 (UTC) using SPRAT (Piascik et al 2014) on the Liverpool Telescope (Steele et al. 2004). The appearance of the spectrum and the measured line velocities are commensurate with normal SNe II.
To summarise, the SN is spectroscopically normal but has a low absolute magnitude and long rise time, it is hosted in a faint dwarf galaxy which is possibly metal poor. Given the unusual nature of this object, we encourage follow-up observations.
