TY - JOUR
T1 - Common Envelope Ejection for a Luminous Red Nova in M101
AU - Blagorodnova, N.
AU - Kotak, R.
AU - Polshaw, J.
AU - Kasliwal, Mansi M.
AU - Cao, Y
AU - Cody, Ann Marie
AU - Doran, G. B.
AU - Elias-Rosa, N.
AU - Fraser, M.
AU - Fremling, C.
AU - Gonzalez-Fernandez, C.
AU - Harmanen, J.
AU - Jencson, J.
AU - Kankare, E.
AU - Kudritzki, R.P.
AU - Kulkarni, Shrinivas R.
AU - Magnier, E. A.
AU - Manulis, I.
AU - Masci, F. J.
AU - Mattila, S.
AU - Nugent, P.
AU - Ochner, Paolo
AU - Pastorello, A.
AU - Reynolds, T.
AU - Smith, K.
AU - Sollerman, J.
AU - Taddia, F.
AU - Terreran, G.
AU - Tomasella, Lina
AU - Turatto, M.
AU - Vreeswijk, P.M.
AU - Wozniak, P.
AU - Zaggia, S.
PY - 2017/1/6
Y1 - 2017/1/6
N2 - 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≤slant -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 ×
{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⊙).
AB - 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≤slant -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 ×
{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⊙).
KW - binaries: close
KW - novae
KW - cataclysmic variables
KW - stars: individual: M101 OT2015-1
KW - PSN J14021678+5426205
KW - stars: massive
KW - stars: winds
KW - outflows
U2 - 10.3847/1538-4357/834/2/107
DO - 10.3847/1538-4357/834/2/107
M3 - Article
SN - 0004-637X
VL - 834
JO - The Astrophysical Journal
JF - The Astrophysical Journal
IS - 2
M1 - 107
ER -