The Evolution of Luminous Red Nova AT 2017jfs in NGC 4470

Abstract

We present the results of our photometric and spectroscopic follow-up of the intermediate-luminosity optical transient AT 2017jfs. At peak, the object reaches an absolute magnitude of Mg=-15.46+-0.15 mag and a bolometric luminosity of 5.5x10^41 erg/s. Its light curve has the double-peak shape typical of Luminous Red Novae (LRNe), with a narrow first peak bright in the blue bands, while the second peak is longer lasting and more luminous in the red and near-infrared (NIR) bands. During the first peak, the spectrum shows a blue continuum with narrow emission lines of H and Fe II. During the second peak, the spectrum becomes cooler, resembling that of a K-type star, and the emission lines are replaced by a forest of narrow lines in absorption. About 5 months later, while the optical light curves are characterized by a fast linear decline, the NIR ones show a moderate rebrightening, observed until the transient disappeared in solar conjunction. At these late epochs, the spectrum becomes reminiscent of that of M-type stars, with prominent molecular absorption bands. The late-time properties suggest the formation of some dust in the expanding common envelope or an IR echo from foreground pre-existing dust. We propose that the object is a common-envelope transient, possibly the outcome of a merging event in a massive binary, similar to NGC4490-2011OT1.

7 pages, 4 figures, 2 Tables (incl. one on-line). Published in A&A Letters

References in corpus (9)

• Empirical Color Transformations Between SDSS Photometry and Other Photometric Systems
• GROND - a 7-channel imager
• PESSTO : survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Objects
• An Intermediate Luminosity Transient in NGC300: The Eruption of a Dust-Enshrouded Massive Star
• Stellar Mergers Are Common
• Shock-powered light curves of luminous red novae as signatures of pre-dynamical mass loss in stellar mergers
• A very faint core-collapse supernova in M85
• SN Hunt 248: a super-Eddington outburst from a massive cool hypergiant
• On the properties of dust and gas in the environs of V838 Monocerotis

Cited by in corpus (18)

• The transitional gap transient AT 2018hso: new insights on the luminous red nova phenomenon
• Light Curve Model for Luminous Red Novae and Inferences about the Ejecta of Stellar Mergers
• Luminous Red Nova AT 2019zhd, a new merger in M 31
• Volumetric rates of Luminous Red Novae and Intermediate Luminosity Red Transients with the Zwicky Transient Facility
• The luminous red nova variety: AT 2020hat and AT 2020kog
• A systematic reclassification of type IIn supernovae
• Observations of the luminous red nova AT 2021biy in the nearby galaxy NGC 4631
• The Carnegie Supernova Project II. Observations of the luminous red nova AT 2014ej
• Gap Transients Interacting with Circumstellar Medium
• Panchromatic evolution of three luminous red novae: Forbidden hugs in pandemic times -- IV
• Lithium in coalesced non-compact stars
• A study in scarlet -- I. Photometric properties of a sample of Intermediate Luminosity Red Transients
• Two-Dimensional Radiation-Hydrodynamic Simulations of Luminous Red Novae
• VVV-WIT-01: highly obscured classical nova or protostellar collision?
• Characteristics and evolution of Be-type high mass X-ray binaries as potential Ultraluminous X-ray Sources
• Spitzer's Last Look at Extragalactic Explosions: Long-Term Evolution of Interacting Supernovae
• Intermediate-luminosity red transients: Spectrophotometric properties and connection to electron-capture supernova explosions
• The fate of the progenitors of luminous red novae: Infrared detection of LRNe years after the outburst