The Type IIn supernova 1994W: evidence for the explosive ejection of a circumstellar envelope

By N. Chugai, S. Blinnikov, R. Cumming, P. Lundqvist, A. Bragaglia, A. Filippenko, D. Leonard, Thomas Matheson, Jesper Sollerman Institute of Astronomy, Ras and 7 more. 2004

182 citations recorded by the source corpus.

We present and analyse spectra of the Type IIn supernova (SN) 1994W obtained between 18 and 203d after explosion. During the luminous phase (first 100 d) the line profiles are composed of three major components: (i) narrow P-Cygni lines with the absorption minima at -700 km s -1; (ii) broad emission lines with blue velocity at zero intensity ∼4000km s -1; and (iii) broad, smooth wings extending out to at least ∼5000kms -1, most apparent in Hα. These components are identified with an expanding circumstellar (CS) envelope, shocked cool gas in the forward post-shock region, and multiple Thomson scattering in the CS envelope, respectively. The absence of broad P-Cygni lines from the SN is the result of the formation of an optically thick, cool, dense shell at the interface of the ejecta and the CS envelope. Models of the SN deceleration and Thomson scattering wings are used to recover the density (n ≈ 10 9cm -3), radial extent [∼(4-5) × 10 15cm] and Thomson optical depth (τ T ≳ 2.5) of the CS envelope during the first month. The plateau-like SN light curve is reproduced by a hydrodynamical model and is found to be powered by a combination of internal energy leakage after the explosion of an extended pre-SN (∼10 15 cm) and subsequent luminosity from CS interaction. The pre-explosion kinematics of the CS envelope is recovered, and is close to homologous expansion with outer velocity ∼1100 km s -1 and a kinematic age of ∼1.5 yr. The high mass (∼0.4M⊙) and kinetic energy (∼2 × 10 48 erg) of the CS envelope, combined with low age, strongly suggest that the CS envelope was explosively ejected ∼1.5 yr prior to the SN explosion.

Subfields: Astronomy and Astrophysics, Instrumentation, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/cb73b39cbc0fb06000081c70a7195b24821bd8e3

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. N. Smith
2. S. Smartt
3. A. Filippenko
4. Stan Woosley
5. Ryan Chornock
6. E. Berger
7. Weidong Li
8. J. C. Wheeler

In Instrumentation

1. N. Smith
2. A. Filippenko
3. S. Smartt
4. Stan Woosley
5. Weidong Li
6. J. Silverman
7. Ryan Chornock
8. R. Foley

In Nuclear and High Energy Physics

1. N. Smith
2. S. Smartt
3. Stan Woosley
4. J. C. Wheeler
5. R. Chevalier
6. Nozomu Tominaga
7. A. Gal-yam
8. S. Valenti

Citations in the corpus

• Shell-shocked Diffusion Model for the Light Curve of SN 2006gy (2007, methodology): “Interaction with an external CSM can, in principle, generate high luminosity as seen in other Type IIn SNe (e.g., Chugai et al. 2004).”
• SHOCK BREAKOUT IN DENSE MASS LOSS: LUMINOUS SUPERNOVAE (2011, methodology): “Chugai et al. (2004) calculated a model for SN 1994W which allows for dense mass loss around the supernova, leading to a peak luminosity at an age of ∼ 20 days.”
• SN 2006gy: Discovery of the Most Luminous Supernova Ever Recorded, Powered by the Death of an Extremely Massive Star like η Carinae (2006, background): “The broad-line profile differs from the smooth broad parts ofH profiles normally seen in SNe IIn (e.g., Chugai et al. 2004).”
• Mass Loss: Its Effect on the Evolution and Fate of High-Mass Stars (2014, background): “…recently, pre-SN eruptive mass loss and connections to LBVs were mostly hypothetical, limited to (reasonable) conjectures supported by the circumstantial evidence that something must deposit a large mass of outflowing H-rich CSM so close to the star (Chugai et al. 2004, Smith et al. 2008, 2010b).”
• GENERALIZED SEMI-ANALYTICAL MODELS OF SUPERNOVA LIGHT CURVES (2011, methodology): “For this reason in §3.3.4 we compare our results with numerical results presented by Chugai et al. (2004), Woosley, Blinnikov & Heger (2007) and Moriya et al. (2011) for the same initial conditions and discuss the differences.”
• Light-curve modelling of superluminous supernova 2006gy: collision between supernova ejecta and a dense circumstellar medium (2012, methodology): “As is shown in the previous works (e.g. Chevalier & Fransson 1994; Chugai 2001; Chugai et al. 2004) and as will be shown in the following sections, the interaction of SN ejecta and a dense CSM results in a dense cool shell between the SN ejecta and the dense CSM.”
• SN 2006jc: A Wolf-Rayet Star Exploding in a Dense He-rich Circumstellar Medium (2006, background): “The short time between these events may have far-reaching implications for the late evolution of massive stars, beyond what we can discuss here; however, it is worth noting that Chugai et al. (2004) determined that Type IIn SN 1994W had an outburst∼1.5 yr prior to explosion.”
• Nearby Supernova Factory Observations of SN 2005gj: Another Type Ia Supernova in a Massive Circumstellar Envelope (2006, methodology): “Such clouds could be similar to fingers fromRayleigh-Taylor instability that produce a corrugated SN-CSM interface in the Chugai et al. (2004a) model for SN 2002ic.”
• SPECTRAL EVOLUTION OF THE EXTRAORDINARY TYPE IIn SUPERNOVA 2006gy (2009, methodology): “In the case of SN 1994W the pre-SN shell was ejected 1.5 yr before explosion in a 2 × 1048 erg event (Chugai et al. 2004), and for SN 1995G it was ejected 8 yr before in a 6× 1048 erg event (Chugai & Danziger 2003).”
• ANALYTICAL LIGHT CURVE MODELS OF SUPERLUMINOUS SUPERNOVAE: χ2-MINIMIZATION OF PARAMETER FITS (2013, methodology): “In addition, a few numerical radiation hydrodynamics simulations have been performed yielding broad-band model LCs with the purpose of reproducing the LCs of some events (Chugai et al. 2004; Moriya et al. 2011, 2012, 2013).”
• INTERACTING SUPERNOVAE AND SUPERNOVA IMPOSTORS: SN 2009ip, IS THIS THE END? (2012, background): “The discrimination between SN impostors (i.e. LBVtype eruptions) and type IIn SNe can be ambiguous (see e.g. the SN 2011ht-like objects, Roming et al. 2012; Mauerhan et al. 2012a; Humphreys et al. 2012; Kankare et al. 2012; Dessart et al. 2009; Chugai et al. 2004).”
• The Unprecedented Third Outburst of SN 2009ip: A Luminous Blue Variable Becomes a Supernova (2012, background): “…the star, the CSM may be created via strong superwinds that last for millennia, in the case of extreme red supergiant progenitors (Smith et al. 2009), or by discrete outbursts that occur rapidly on month-toyear timescales (see Chugai et al. 2004; Chugai & Danziger 1994; Smith et al. 2010a, 2008a).”
• On the Role of Continuum-driven Eruptions in the Evolution of Very Massive Stars and Population III Stars (2006, background): “Some examples are the radio-bright SN1988Z with a nebula as massive as 15 M⊙ (Aretxaga et al. 1999; Williams et al. 2002; Van Dyk et al. 1993; Chugai & Danziger 1994), as well as similar dense shells around SN2001em (Chugai & Chevalier 2006), SN1994W (Chugai et al. 2004), SN1998S (Gerardy et al. 200”
• DISCOVERY OF PRECURSOR LUMINOUS BLUE VARIABLE OUTBURSTS IN TWO RECENT OPTICAL TRANSIENTS: THE FITFULLY VARIABLE MISSING LINKS UGC 2773-OT AND SN 2009ip (2009, background): “Note, however, that the spec- tral evolution of well-studied SNe IIn such as SN 1994W and SN 2006gy (Chugai et al. 2004; Smith et al. 2010) shows that the Balmer decrement is highly time dependent, steepening as the emitting layer expands, thins, and cools.”
• Observed Fractions of Core-Collapse Supernova Types and Initial Masses of their Single and Binary Progenitor Stars (2010, background): “Observational clues from CSM interaction in SNe IIn indicate that heavy mass-loss sometimes occurs shortly before core collapse (e.g. Chugai et al. 2004; Smith & McCray 2007; Smith et al. 2007, 2008b, 2010); if heavy mass-loss is concentrated in brief events during the last few thousand years…”
• Pulsational Pair-instability Supernovae (2016, background): “Chugai et al. (2004) have inferred the ejection of a massive circumstellar shell 1.5 years before the explosion of Type IIn SN 1994W.”
• Luminous blue variable eruptions and related transients: diversity of progenitors and outburst properties (2010, background): “Most bona-fide SNe IIn have line widths of 1000–4000 km s−1 (e.g., Chugai et al. 2004; Smith et al. 2008, 2009b, 2010b; Filippenko 1997); even some of the most luminous SNe known have lines as narrow as 1000 km s−1 (Smith et al. 2008, 2010b; Prieto et al. 2007).”
• Massive stars exploding in a He-rich circumstellar medium. I. Type Ibn (SN 2006jc-like) events (2008, background): “…CSM (e.g SNe 1983K, 1993ad and 1994W, Niemela et al. 1985; Phillips et al. 1990; Pollas et al. 1993; Tsvetkov & Pavlyuk 1995; Sollerman et al. 1998; Chugai et al. 2004), but also in more classical non-interacting type II SNe (e.g. SNe 2005cs and 2006bp, Pastorello et al. 2008b; Quimby et al. 2007).”