We present the results of the monitoring campaign of the Type IIn supernova (SN) 2018cnf (a.k.a. ASASSN-18mr). It was discovered about ten days before the maximum light (on MJD = 58 293.4 ± 5.7 in the V band, with MV = ?18.13 ± 0.15 mag). The multiband light curves show an immediate post-peak decline with some minor luminosity fluctuations, followed by a flattening starting about 40 days after maximum. The early spectra are relatively blue and show narrow Balmer lines with P Cygni profiles. Additionally, Fe II, O I, He I, and Ca II are detected. The spectra show little evolution with time and with intermediate-width features becoming progressively more prominent, indicating stronger interaction of the SN ejecta with the circumstellar medium. The inspection of archival images from the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) survey has revealed a variable source at the SN position with a brightest detection in December 2015 at Mr = ?14.66 ± 0.17 mag. This was likely an eruptive phase from the massive progenitor star that started from at least mid-2011, and that produced the circumstellar environment within which the star exploded as a Type IIn SN. The overall properties of SN 2018cnf closely resemble those of transients such as SN 2009ip. This similarity favours a massive hypergiant, perhaps a luminous blue variable, as progenitor for SN 2018cnf.
Bibliographical noteFunding Information:
Acknowledgements. We thank the anonymous referee for insightful comments that helped to improve the paper. D.A.H, C.M., and G.H. were supported by NSF grant AST-1313484. S.B., P.C., and S.D. acknowledge Project 11573003 supported by NSFC. This research uses data obtained through the Telescope Access Program (TAP), which has been funded by the National Astronomical Observatories of China, the Chinese Academy of Sciences, and the Special Fund for Astronomy from the Ministry of Finance. M.G. is supported by the Polish National Science Centre grant OPUS 2015/17/B/ST9/03167. T.W. is funded in part by European Research Council grant 320360 and by European Commission grant 730980. E.Y.H., C.A., and S.K. acknowledge the support provided by the National Science Foundation under Grant No. AST-1613472. M.F. is supported by a Royal Society – Science Foundation Ireland University Research Fellowship. M.M.P. acknowledges support from the National Science Foundation under grants AST-1008343 and AST-1613426. C.T., A.dU.P., D.A.K., and L.I. acknowledge support from the Spanish research project AYA2017-89384-P. C.T. and A.dU.P. acknowledge support from funding associated to Ramón y Cajal fellowships (RyC-2012-09984 and RyC-2012-09975). D.A.K. and L.I. acknowledge support from funding associated to Juan de la Cierva Incorporación fellowships (IJCI-2015-26153 and IJCI-2016-30940). G.P and O.R. acknowledge support by the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. L.W. is sponsored, in part, by the Chinese Academy of Sciences (CAS), through a grant to the CAS South America Center for Astronomy (CASSACA) in Santiago, Chile. The NOT data were obtained through the NOT Unbiased Transient Survey (NUTS; http://csp2.lco.cl/not/), which is supported in part by the Instrument Center for Danish Astrophysics (IDA). This work is based, in part, on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, under ESO programme 0101.D-0202, and as part of PESSTO (the Public ESO Spectroscopic Survey for Transient Objects Survey) ESO program 188.D-3003, 191.D-0935, 197.D-1075. This work also makes use of data from the Las Cumbres Observatory Network as part of the Global Supernova Project; the Nordic Optical Telescope (NOT), operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias; the 1.82 m Copernico Telescope of INAF-Asiago Observatory; the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Insti-tuto de Astrofísica de Canarias, in the Island of La Palma; the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile; and the Liverpool Telescope operated on the island of La Palma by Liverpool John Moores University at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias with financial support from the UK Science and Technology Facilities Council. It is also based in part on observations at Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory (NOAO), which is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under a cooperative agreement with the National Science Foundation. ASAS-SN is supported by the Gordon and Betty Moore Foundation through grant GBMF5490 to the Ohio State University and NSF grant AST-1515927. Development of ASAS-SN has been supported by NSF grant AST-0908816, the Mt. Cuba Astronomical Foundation, the Center for Cosmology and AstroParticle Physics at the Ohio State University, the Chinese Academy of Sciences South America Center for Astronomy (CAS-SACA), the Villum Foundation, and George Skestos. The Pan-STARRS1 Surveys (PS1) have been made possible through contributions of the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg, and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, Queen’s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, STScI, NASA under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the US NSF under Grant No. AST-1238877, the University of Maryland, and Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation. This research has made use of the NASA-IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
© ESO 2019
- Stars: winds
- Supernovae: general
- Supernovae: individual: SN 2009ip
- Supernovae: individual: SN 2018cnf