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

DOI: 
10.1051/0004-6361/201935511
Publication date: 
01/05/2019
Main author: 
Pastorello, A.
IAA authors: 
Cano, Z.;Kann, D. A.;de Ugarte Postigo, A.;Izzo, L.;Thöne, C. C.
Authors: 
Pastorello, A.;Chen, T. -W.;Cai, Y. -Z.;Morales-Garoffolo, A.;Cano, Z.;Mason, E.;Barsukova, E. A.;Benetti, S.;Berton, M.;Bose, S.;Bufano, F.;Callis, E.;Cannizzaro, G.;Cartier, R.;Chen, Ping;Dong, Subo;Dyrbye, S.;Elias-Rosa, N.;Flörs, A.;Fraser, M.;Geier, S.;Goranskij, V. P.;Kann, D. A.;Kuncarayakti, H.;Onori, F.;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.;de Ugarte Postigo, A.;Izzo, L.;Inserra, C.;Kankare, E.;Maguire, K.;Smith, K. W.;Stalder, B.;Tartaglia, L.;Thöne, C. C.;Valerin, G.;Young, D. R.
Journal: 
Astronomy and Astrophysics
Refereed: 
Yes
Publication type: 
Article
Volume: 
625
Pages: 
L8
Abstract: 
We present the results of our photometric and spectroscopic follow-up of the intermediate-luminosity optical transient <ASTROBJ>AT 2017jfs</ASTROBJ>. At peak, the object reaches an absolute magnitude of M<SUB>g</SUB> = -15.46 ± 0.15 mag and a bolometric luminosity of 5.5 × 10<SUP>41</SUP> erg s<SUP>-1</SUP>. 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 <ASTROBJ>NGC 4490-2011OT1</ASTROBJ>. Table A.1 is only available at the CDS via anonymous ftp to <A href='http://cdsarc.u-strasbg.fr/'>http://cdsarc.u-strasbg.fr</A> (ftp://130.79.128.5) or via <A href='http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/625/L8'>http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/625/L8</A>
Database: 
ADS
SCOPUS
URL: 
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85071258065&doi=10.1051%2f0004-6361%2f201935511&partnerID=40&md5=a9acf4d0269df1183ed6173a9bcd73bb
ADS Bibcode: 
2019A&A...625L...8P
Keywords: 
binaries: close;stars: massive;supernovae: individual: AT 2017jfs;supernovae: individual: NGC 440-2011OT1;stars: winds;outflows