AT 2017be - a new member of the class of intermediate-luminosity red transients
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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.
Originalsprog | Engelsk |
---|---|
Tidsskrift | Monthly Notices of the Royal Astronomical Society |
Vol/bind | 480 |
Udgave nummer | 3 |
Sider (fra-til) | 3424-3445 |
ISSN | 0035-8711 |
DOI | |
Status | Udgivet - 1 nov. 2018 |
Links
- https://arxiv.org/pdf/1807.11676.pdf
Indsendt manuskript
ID: 204126339