DISCOVERY OF PRECURSOR LUMINOUS BLUE VARIABLE OUTBURSTS IN TWO RECENT OPTICAL TRANSIENTS: THE FITFULLY VARIABLE MISSING LINKS UGC 2773-OT AND SN 2009ip

By N. Smith, Adam A. Miller, Weidong Li, A. Filippenko, J. Silverman, Andrew W. Howard, P. Nugent, G. Marcy, Joshua S. Bloom, A. Ghez and 4 more. 2009

176 citations recorded by the source corpus.

We present progenitor-star detections, light curves, and optical spectra of supernova (SN) 2009ip and the 2009 optical transient in UGC 2773 (U2773-OT), which were not genuine SNe. Precursor variability in the decade before outburst indicates that both of the progenitor stars were luminous blue variables (LBVs). Their pre-outburst light curves resemble the S Doradus phases that preceded giant eruptions of the prototypical LBVs η Carinae and SN 1954J (V12 in NGC 2403), with intermediate progenitor luminosities. Hubble Space Telescope detections a decade before discovery indicate that the SN 2009ip and U2773-OT progenitors were supergiants with likely initial masses of 50–80 M☉ and ≳20 M☉, respectively. Both outbursts had spectra befitting known LBVs, although in different physical states. SN 2009ip exhibited a hot LBV spectrum with characteristic speeds of 550 km s−1, plus evidence for faster material up to 5000 km s−1, resembling the slow Homunculus and fast blast wave of η Carinae. In contrast, U2773-OT shows a forest of narrow absorption and emission lines comparable to that of S Dor in its cool state, plus [Ca ii] emission and an infrared excess indicative of dust, similar to SN 2008S and the 2008 optical transient in NGC 300 (N300-OT). The [Ca ii] emission is probably tied to a dusty pre-outburst environment, and is not a distinguishing property of the outburst mechanism. The LBV nature of SN 2009ip and U2773-OT may provide a critical link between historical LBV eruptions, while U2773-OT may provide a link between LBVs and the unusual dust-obscured transients SN 2008S and N300-OT. Future searches will uncover more examples of precursor LBV variability of this kind, providing key clues that may help unravel the instability driving LBV eruptions in massive stars.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/ccc70b9d62f00aeafe9b84ceefd214c6eb976796

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In Astronomy and Astrophysics

1. S. Smartt
2. N. Smith
3. E. Berger
4. A. Filippenko
5. Stan Woosley
6. Ryan Chornock
7. S. Valenti
8. Bing Zhang

Citations in the corpus

• Pulsational Pair-instability Supernovae (2016, background): “Later, Smith et al. (2010a) showed that this event required a kinetic energy of 5×1051 erg which may be just out of reach.”
• Luminous blue variable eruptions and related transients: diversity of progenitors and outburst properties (2010, methodology): “Based on the [Ca ii] emission lines and associations with dusty environments (Smith et al. 2009a, 2010; Prieto et al. 2008), however, it is possible that the progenitor could potentially be intrinsically more luminous than this.”
• Unifying Type II Supernova Light Curves with Dense Circumstellar Material (2016, background): “This evidence can come in the form of direct detections of preSN outbursts (e.g., Foley et al. 2007; Pastorello et al. 2007; Smith et al. 2010; Foley et al. 2011; Mauerhan et al. 2013; Pastorello et al. 2013) or inferred from the dense CSM needed to explain SN light curves (e.g., Smith & McCray…”
• The Unprecedented Third Outburst of SN 2009ip: A Luminous Blue Variable Becomes a Supernova (2012, methodology): “The first 2009 outburst was very brief compared to other LBV-like eruptions, lasting only a few days (Smith et al. 2010b), instead of a few months or more like most LBV eruptions (Smith et al. 2011).”
• Observational Constraints on the Progenitors of Core-Collapse Supernovae: The Case for Missing High-Mass Stars (2015, background): “After the initial discovery of a non-terminal, but luminous (M ∼ −14) outburst in 2009 (Maza et al. 2009) at which point it was named SN2009ip, a luminous progenitor star (MV = −10) was detected in HST archival imaging taken in 1999 (Smith et al. 2010; Foley et al. 2011).”
• Dawes Review 6: The Impact of Companions on Stellar Evolution (2016, unknown): “…have LBV-like mass-loss rates and in four cases progenitors are known, e.g., SN 1961V (Smith et al., 2011b; Kochanek, Szczygiel, & Stanek, 2011), 2005gl (GalYam & Leonard, 2009), 2010jl (Smith et al., 2011b), and 2009ip (Smith et al. 2010, Foley et al. 2011; see also Smith (2014) for a review).”
• Mass Loss: Its Effect on the Evolution and Fate of High-Mass Stars (2014, methodology): “A number of extragalactic LBV-like eruptions show spectra that closely resemble shock-powered Type IIn SNe and also show evidence for extremely fast ejecta that may signify a shock-powered event, such as the precursor outbursts of SN2009ip (Foley et al. 2011, Smith et al. 2010a).”
• Fundamental properties of core-collapse Supernova and GRB progenitors: predicting the look of massive stars before death (2013, background): “In a few cases, a very luminous progenitor (MV ∼ −10 mag) has been detected in pre-explosion images, such as the progenitors of SN 2005gl (Gal-Yam & Leonard 2009), SN 2009ip (Smith et al. 2010; Mauerhan et al. 2013; Foley et al. 2011; Pastorello et al. 2013), and SN 2010jl (Smith et al. 2011b).”
• A PANCHROMATIC VIEW OF THE RESTLESS SN 2009ip REVEALS THE EXPLOSIVE EJECTION OF A MASSIVE STAR ENVELOPE (2013, methodology): “Among the most important findings is the presence of blue-shifted absorption lines corresponding to ejecta traveling at a velocity of 2000−7000kms−1 during the 2009 outbursts (Smith et al. 2010b, Foley et al. 2011), extending to v ∼ 13000kms−1 in Semptember 2011 (Pastorello et al. 2012).”
• Progenitor mass constraints for core-collapse supernovae from correlations with host galaxy star formation⋆ (2012, background): “Also, a number of authors have linked LBVs to individual SNIIn and SN ‘impostors’ (e.g. Trundle et al. 2008; Smith et al. 2010; Kiewe et al. 2012), while the one direct detection of an SNIIn that exists points to a very massive star (GalYam et al. 2007).”
• HIGH-DENSITY CIRCUMSTELLAR INTERACTION IN THE LUMINOUS TYPE IIn SN 2010jl: THE FIRST 1100 DAYS (2013, background): “Besides the discussed SNe, two recent Type IIn SNe SN 2009ip (Smith et al. 2010; Foley et al. 2011; Pastorello et al. 2013; Mauerhan et al. 2013) and SN 2010mc (Ofek et al. 2013) have received considerable attention.”
• PREPARING FOR AN EXPLOSION: HYDRODYNAMIC INSTABILITIES AND TURBULENCE IN PRESUPERNOVAE (2013, background): “Progenitor star detections We now have four directly detected quiescent progenitors of SNe IIn with rough mass estimates.”
• INTERACTING SUPERNOVAE AND SUPERNOVA IMPOSTORS: SN 2009ip, IS THIS THE END? (2012, methodology): “The same distance modulus (µ = 31.55± 0.15 mag) and interstellar extinction (AR = 0.051) adopted by Smith et al. (2010) and Mauerhan et al. (2012b) for SN 2009ip have been used in the absolute R-band light curve of Figure 2.”
• Production of dust by massive stars at high redshift (2011, background): “The Type IIn SN 2005ip is an example where dust was formed in the post-shocked shell (Fox et al, 2009; Smith et al, 2009).”
• The death of massive stars – I. Observational constraints on the progenitors of Type II-P supernovae (2008, methodology): “Smith et al. (2010) and Foley et al. (2011) identified the progenitor as a star of ∼60 M using archival HST images.”