AT 2017be - a new member of the class of intermediate-luminosity red transients
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AT 2017be - a new member of the class of intermediate-luminosity red transients. / Cai, Y.-Z.; Pastorello, A.; Fraser, M.; Botticella, M. T.; Gall, C.; Arcavi, I.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Harmanen, J.; Hosseinzadeh, G.; Howell, D. A.; Isern, J.; Kangas, T.; Kankare, E.; Kuncarayakti, H.; Lundqvist, P.; Mattila, S.; McCully, C.; Reynolds, T. M.; Somero, A.; Stritzinger, M. D.; Terreran, G.
I: Monthly Notices of the Royal Astronomical Society, Bind 480, Nr. 3, 01.11.2018, s. 3424-3445.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - AT 2017be - a new member of the class of intermediate-luminosity red transients
AU - Cai, Y.-Z.
AU - Pastorello, A.
AU - Fraser, M.
AU - Botticella, M. T.
AU - Gall, C.
AU - Arcavi, I.
AU - Benetti, S.
AU - Cappellaro, E.
AU - Elias-Rosa, N.
AU - Harmanen, J.
AU - Hosseinzadeh, G.
AU - Howell, D. A.
AU - Isern, J.
AU - Kangas, T.
AU - Kankare, E.
AU - Kuncarayakti, H.
AU - Lundqvist, P.
AU - Mattila, S.
AU - McCully, C.
AU - Reynolds, T. M.
AU - Somero, A.
AU - Stritzinger, M. D.
AU - Terreran, G.
PY - 2018/11/1
Y1 - 2018/11/1
N2 - We report the results of our spectrophotometric monitoring campaign for AT 2017be in NGC 2537. Its light curve reveals a fast rise to an optical maximum, followed by a plateau lasting about 30 d, and finally a fast decline. Its absolute peak magnitude (Mr ≃ -12 mag) is fainter than that of core-collapse supernovae, and is consistent with those of supernova impostors and other intermediate-luminosity optical transients. The quasi-bolometric light-curve peaks at ˜2 × 1040 erg s-1, and the late-time photometry allows us to constrain an ejected 56Ni mass of ˜8 × 10-4 M⊙. The spectra of AT 2017 be show minor evolution over the observational period, a relatively blue continuum showing at early phases, which becomes redder with time. A prominent H α emission line always dominates over other Balmer lines. Weak Fe II features, Ca II H&K, and the Ca II NIR triplet are also visible, while P-Cygni absorption troughs are found in a high-resolution spectrum. In addition, the [Ca II] λλ7291, 7324 doublet is visible in all spectra. This feature is typical of intermediate-luminosity red transients (ILRTs), similar to SN 2008S. The relatively shallow archival Spitzer data are not particularly constraining. On the other hand, a non-detection in deeper near-infrared HST images disfavours a massive Luminous Blue Variable eruption as the origin for AT 2017be. As has been suggested for other ILRTs, we propose that AT 2017be is a candidate for a weak electron-capture supernova explosion of a superasymptotic giant branch star, still embedded in a thick dusty envelope.
AB - We report the results of our spectrophotometric monitoring campaign for AT 2017be in NGC 2537. Its light curve reveals a fast rise to an optical maximum, followed by a plateau lasting about 30 d, and finally a fast decline. Its absolute peak magnitude (Mr ≃ -12 mag) is fainter than that of core-collapse supernovae, and is consistent with those of supernova impostors and other intermediate-luminosity optical transients. The quasi-bolometric light-curve peaks at ˜2 × 1040 erg s-1, and the late-time photometry allows us to constrain an ejected 56Ni mass of ˜8 × 10-4 M⊙. The spectra of AT 2017 be show minor evolution over the observational period, a relatively blue continuum showing at early phases, which becomes redder with time. A prominent H α emission line always dominates over other Balmer lines. Weak Fe II features, Ca II H&K, and the Ca II NIR triplet are also visible, while P-Cygni absorption troughs are found in a high-resolution spectrum. In addition, the [Ca II] λλ7291, 7324 doublet is visible in all spectra. This feature is typical of intermediate-luminosity red transients (ILRTs), similar to SN 2008S. The relatively shallow archival Spitzer data are not particularly constraining. On the other hand, a non-detection in deeper near-infrared HST images disfavours a massive Luminous Blue Variable eruption as the origin for AT 2017be. As has been suggested for other ILRTs, we propose that AT 2017be is a candidate for a weak electron-capture supernova explosion of a superasymptotic giant branch star, still embedded in a thick dusty envelope.
KW - stars: AGB and post-AGB
KW - stars: mass-loss
KW - supernovae: general
KW - galaxies: individual: NGC 2537
KW - supernovae: individual: AT 2017be
U2 - 10.1093/mnras/sty2070
DO - 10.1093/mnras/sty2070
M3 - Journal article
VL - 480
SP - 3424
EP - 3445
JO - Royal Astronomical Society. Monthly Notices
JF - Royal Astronomical Society. Monthly Notices
SN - 0035-8711
IS - 3
ER -
ID: 204126339