The evolution of luminous red nova AT 2017jfs in NGC 4470

Journal
Date Issued
2019
Author(s)
•
Chen, T. -W.
•
Cai, Y. -Z.
•
Morales-Garoffolo, A.
•
Cano, Z.
•
•
Barsukova, E. A.
•
•
Berton, M.
•
Bose, S.
•
•
Callis, E.
•
Cannizzaro, G.
•
Cartier, R.
•
Chen, Ping
•
Dong, Subo
•
Dyrbye, S.
•
•
Flörs, A.
•
Fraser, M.
•
Geier, S.
•
Goranskij, V. P.
•
Kann, D. A.
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Kuncarayakti, H.
•
•
Reguitti, A.
•
Reynolds, T.
•
Losada, I. R.
•
Sagués Carracedo, A.
•
Schweyer, T.
•
Smartt, S. J.
•
Tatarnikov, A. M.
•
Valeev, A. F.
•
Vogl, C.
•
Wevers, T.
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de Ugarte Postigo, A.
•
Izzo, L.
•
Inserra, C.
•
Kankare, E.
•
Maguire, K.
•
Smith, K. W.
•
Stalder, B.
•
•
Thöne, C. C.
•
Valerin, G.
•
Young, D. R.
DOI
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 5.5 × 1041 erg s-1. 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 disappears 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 NGC 4490-2011OT1.

Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/625/L8

Volume
625
Start page
L8
Uri
Url
Issn Identifier
0004-6361
Ads BibCode
2019A&A...625L...8P
Rights
open.access
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