Common Envelope Ejection for a Luminous Red Nova in M101

Creators: Blagorodnova, N.; Kotak, R.; Polshaw, J.; Kasliwal, M. M.; Cao, Y.; Cody, A. M.; Doran, G. B.; Elias-Rosa, N.; Fraser, M.; Fremling, C.; Gonzalez-Fernandez, C.; Harmanen, J.; Jencson, J.; Kankare, E.; Kudritzki, R.-P.; Kulkarni, S. R.; Magnier, E. A.; Manulis, I.; Masci, F. J.; Mattila, S.; Nugent, P.; Ochner, P.; Pastorello, A.; Reynolds, T.; Smith, K.; Sollerman, J.; Taddia, F.; Terreran, G.; Tomasella, L.; Turatto, M.; Vreeswijk, P. M.; Wozniak, P.; Zaggia, S.

Abstract

We present the results of optical, near-infrared, and mid-infrared observations of M101 OT2015-1 (PSN J14021678+5426205), a luminous red transient in the Pinwheel galaxy (M101), spanning a total of 16 years. The light curve showed two distinct peaks with absolute magnitudes M_r ≤ -12.4 and M_r ≃ -12, on 2014 November 11 and 2015 February 17, respectively. The spectral energy distributions during the second maximum show a cool outburst temperature of ≈ 3700 K and low expansion velocities (≈-300 km s^(−1)) for the H i, Ca ii, Ba ii, and K i lines. From archival data spanning 15–8 years before the outburst, we find a single source consistent with the optically discovered transient, which we attribute to being the progenitor; it has properties consistent with being an F-type yellow supergiant with L ~ 8.7 x 10^4 L_⊙, T_(eff) ≈ 7000 K, and an estimated mass of M_1 = 18 ± 1 M_⊙. This star has likely just finished the H-burning phase in the core, started expanding, and is now crossing the Hertzsprung gap. Based on the combination of observed properties, we argue that the progenitor is a binary system, with the more evolved system overfilling the Roche lobe. Comparison with binary evolution models suggests that the outburst was an extremely rare phenomenon, likely associated with the ejection of the common envelope of a massive star. The initial mass of the primary fills the gap between the merger candidates V838 Mon (5−10 M_⊙) and NGC 4490-OT (30 M_⊙).

Additional Information

© 2017. The American Astronomical Society. Received 2016 July 22; revised 2016 October 21; accepted 2016 October 26; published 2017 January 6. The research leading to these results has received funding from the European Union Seventh Framework Programme ([FP7/2007-2013] under grant agreement no. 264895. This work was partly supported by the European Union FP7 programme through ERC grant no. 320360. This work was supported, in whole or in part, by the European Science Foundation under the GREAT ESF RNP programme. This work was supported by the GROWTH project funded by the National Science Foundation under grant no. 1545949. LANL participation in iPTF was funded by the US Department of Energy as part of the Laboratory Directed Research and Development program. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/IRFU, at the Canada–France–Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at Terapix available at the Canadian Astronomy Data Centre as part of the Canada–France–Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. This paper makes use of data obtained from the Isaac Newton Group Archive, which is maintained as part of the CASU Astronomical Data Centre at the Institute of Astronomy, Cambridge. This work is partly based on observations obtained with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain. This work is partly based on observations made with the William Hershell Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofsica de Canarias. The Gran Telescopio Canarias (GTC) operated on the island of La Palma at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. This work is partly based on data from Copernico 1.82 m telescope operated by INAF Osservatorio Astronomico di Padova. NER, AP, GT, and MT are partially supported by the PRIN-INAF 2014 with the project "Transient universe: unveiling new types of stellar explosions with PESSTO." Finally, NBM would like to thank the anonymous referee, who helped to improve the manuscript, Robert G. Izzard, Philipp Podsiadlowski, Lars Bildsten, E. Sterl Phinney, and Noam Soker for helpful discussions, and Pablo and Lucia Solis, and Israel Zenteno for the motivation. Facilities: Asiago:Copernico - Asiago Observatory's Copernico Telescope, CFHT - , GTC - , Hale - , ING:Newton - , ING:Herschel - , Keck:I - , LBT - , Liverpool:2m - , NOT - , PO:1.2m - , PO:1.5m - , PS1 - , Sloan - , Spitzer - , UKIRT. - Software: BPASS v1.0, BPASS v2.0, EMCEE (Foreman-Mackey et al. 2013), IRAF, NOTCAM (v2.54), PTFIDE (Masci et al. 2016), PYRAF, SNOoPY.

Attached Files

Published - Blagorodnova_2017_ApJ_834_107.pdf

Files

Blagorodnova_2017_ApJ_834_107.pdf

Files (4.7 MB)

Name	Size	Download all
Blagorodnova_2017_ApJ_834_107.pdf md5:2f726598ca1baf4337af613f95b332be	4.7 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes