Aarhus University Seal / Aarhus Universitets segl

Forbidden hugs in pandemic times: II. the luminous red nova variety: At 2020hat and at 2020kog

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

  • A. Pastorello, Astronomical Observatory of Padua
  • ,
  • G. Valerin, Astronomical Observatory of Padua, University of Padova
  • ,
  • M. Fraser, University College Dublin
  • ,
  • N. Elias-Rosa, Astronomical Observatory of Padua, CSIC
  • ,
  • S. Valenti, University of California at Davis
  • ,
  • A. Reguitti, Astronomical Observatory of Padua, Universidad Andres Bello, Instituto Milenio de Astrofísica
  • ,
  • P. A. Mazzali, Liverpool John Moores University, Max Planck Institute for Astrophysics
  • ,
  • R. C. Amaro, University of Arizona
  • ,
  • J. E. Andrews, University of Arizona
  • ,
  • J. Jencson, University of Arizona
  • ,
  • M. Lundquist, University of Arizona
  • ,
  • D. E. Reichart, University of North Carolina
  • ,
  • D. J. Sand, Steward Observatory, University of Arizona, Tucson, University of Arizona
  • ,
  • S. Wyatt, University of Arizona
  • ,
  • S. J. Smartt, Queen's University Belfast
  • ,
  • K. W. Smith, Astrophysics Research Centre, Queen's University Belfast
  • ,
  • S. Srivastav, Queen's University Belfast
  • ,
  • Y. Z. Cai, Physics Department and Tsinghua Center for Astrophysics (THCA), Tsinghua University
  • ,
  • E. Cappellaro, Astronomical Observatory of Padua
  • ,
  • S. Holmbo
  • A. Fiore, Astronomical Observatory of Padua, University of Padova
  • ,
  • D. Jones, Instituto Astrofisico de Canarias, University of La Laguna
  • ,
  • E. Kankare, University of Turku
  • ,
  • E. Karamehmetoglu
  • P. Lundqvist, Stockholm University
  • ,
  • A. Morales-Garoffolo, University of Cádiz
  • ,
  • T. M. Reynolds, University of Turku
  • ,
  • M. D. Stritzinger
  • S. C. Williams, University of Turku
  • ,
  • K. C. Chambers, University of Hawai'i at Manoa
  • ,
  • T. J.L. De Boer, University of Hawai'i at Manoa
  • ,
  • M. E. Huber, University of Hawai'i at Manoa
  • ,
  • A. Rest, Space Telescope Science Institute, Johns Hopkins University
  • ,
  • R. Wainscoat, University of Hawai'i at Manoa

We present the results of our monitoring campaigns of the luminous red novae (LRNe) AT 2020hat in NGC 5068 and AT 2020kog in NGC 6106. The two objects were imaged (and detected) before their discovery by routine survey operations. They show a general trend of slow luminosity rise, lasting at least a few months. The subsequent major LRN outbursts were extensively followed in photometry and spectroscopy. The light curves present an initial short-duration peak, followed by a redder plateau phase. AT 2020kog is a moderately luminous event peaking at ∼7 × 1040 erg s-1, while AT 2020hat is almost one order of magnitude fainter than AT 2020kog, although it is still more luminous than V838 Mon. In analogy with other LRNe, the spectra of AT 2020kog change significantly with time. They resemble those of type IIn supernovae at early phases, then they become similar to those of K-type stars during the plateau, and to M-type stars at very late phases. In contrast, AT 2020hat already shows a redder continuum at early epochs, and its spectrum shows the late appearance of molecular bands. A moderate-resolution spectrum of AT 2020hat taken at +37 d after maximum shows a forest of narrow P Cygni lines of metals with velocities of 180 km s-1, along with an Hα emission with a full-width at half-maximum velocity of 250 km s-1. For AT 2020hat, a robust constraint on its quiescent progenitor is provided by archival images of the Hubble Space Telescope. The progenitor is clearly detected as a mid-K type star, with an absolute magnitude of MF606W = -3.33 ± 0.09 mag and a colour of F606W - F814W = 1.14 ± 0.05 mag, which are inconsistent with the expectations from a massive star that could later produce a core-collapse supernova. Although quite peculiar, the two objects nicely match the progenitor versus light curve absolute magnitude correlations discussed in the literature.

Original languageEnglish
JournalAstronomy and Astrophysics
Volume647
ISSN0004-6361
DOIs
Publication statusPublished - 1 Mar 2021

Bibliographical note

Funding Information:
Acknowledgements. We thank David Buckley for providing acquisition imaging taken with the Southern African Large Telescope (SALT), and Paolo Ochner for providing a few images taken with the Copernico Telescope of Asiago (INAF-Osservatorio Astronomico di Padova). We are grateful to the referee V. Goranskij for carefully reading the manuscript and for the insightful comments. MF gratefully acknowledges the support of a Royal Society – Science Foundation Ireland University Research Fellowship. Research by SV and YD is supported by NSF grants AST–1813176 and AST-2008108. Time domain research by DJS is supported by NSF grants AST-1813466, 1908972, and by the Heising-Simons Foundation under grant #2020-1864. YZC is supported in part by National Natural Science Foundation of China (NSFC grants 12033003, 11633002, 11325313, and 11761141001), National Program on Key Research and Development Project (grant no. 2016YFA0400803), and Ma Huateng Foun- dation. DJ acknowledges support from the State Research Agency (AEI) of the Spanish Ministry of Science, Innovation and Universities (MCIU) and the European Regional Development Fund (FEDER) under grant AYA2017-83383-P. DJ also acknowledges support under grant P/308614 financed by funds transferred from the Spanish Ministry of Science, Innovation and Universities, charged to the General State Budgets and with funds transferred from the General Budgets of the Autonomous Community of the Canary Islands by the Ministry of Economy, Industry, Trade and Knowledge. SJS and KWS acknowledge funding from STFC Grants ST/P000312/1, ST/T000198/1 and ST/S006109/1. EC and AF are partially supported by the PRIN-INAF 2017 with the project Towards the SKA and CTA era: discovery, localisation, and physics of transients sources (P.I. M. Giroletti). MS is supported by generous grants from Villum FONDEN (13261,28021) and by a project grant (8021-00170B) from the Independent Research Fund Denmark. This work is based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias; the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, in the Island of La Palma; 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 Insti-tuto de Astrofísica de Canarias with financial support from the UK Science and Technology Facilities Council; the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. This work makes also use of observations from the LCOGT network. This work has made use of data from the Asteroid Terrestrial-impact Last Alert System (ATLAS) project. ATLAS is primarily funded to search for near earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen’s University Belfast, the Space Telescope Science Institute, and the South African Astronomical Observatory, and The Millennium Institute of Astrophysics (MAS), Chile. The Pan-STARRS1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by 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, the Queen’s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Grant No. AST-1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation. This publication is partially based on observations obtained with the Samuel Oschin 48-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Grant No. AST-1440341 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, the University of Washington, Deutsches Elektronen-Synchrotron and Humboldt University, Los Alamos National Laboratories, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, and Lawrence Berkeley National Laboratories. Operations are conducted by COO, IPAC, and UW. 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. This publication made also use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by NASA and the NSF. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.

Publisher Copyright:
© ESO 2021.

    Research areas

  • Binaries: close, Outflows, Stars: individual: AT 2020hat, Stars: individual: AT 2020kog, Stars: individual: V1309 Sco, Stars: individual: V838 Mon, Stars: winds

See relations at Aarhus University Citationformats

ID: 219807193