A1 Refereed original research article in a scientific journal
The evolution of luminous red nova AT 2017jfs in NGC 4470
Authors: A. Pastorello, T.-W. Chen, Y.-Z. Cai, A. Morales-Garoffolo, Z. Cano, E. Mason, E. A. Barsukova, S. Benetti, M. Berton, S. Bose, F. Bufano, E. Callis, G. Cannizzaro, R. Cartier, Ping Chen, Subo Dong, S. Dyrbye, N. Elias-Rosa, A. Flörs, M. Fraser, S. Geier, V. P. Goranskij, D. A. Kann, H. Kuncarayakti, F. Onori, A. Reguitti, T. Reynolds, I. R. Losada, A. Sagués Carracedo, T. Schweyer, S. J. Smartt, A. M. Tatarnikov, A. F. Valeev, C. Vogl, T. Wevers, A. de Ugarte Postigo, L. Izzo, C. Inserra, E. Kankare, K. Maguire, K. W. Smith, B. Stalder, L. Tartaglia, C. C. Thöne, G. Valerin, D. R. Young
Publisher: EDP SCIENCES S A
Publication year: 2019
Journal: Astronomy and Astrophysics
Journal name in source: ASTRONOMY & ASTROPHYSICS
Journal acronym: ASTRON ASTROPHYS
Article number: L8
Volume: 625
Number of pages: 7
ISSN: 1432-0746
eISSN: 1432-0746
DOI: https://doi.org/10.1051/0004-6361/201935511
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/40893549
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 M-g = 15.46 +/- 0.15 mag and a bolometric luminosity of 5.5 x 10(41) 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 NGC4490-2011OT1.
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