A panchromatic view of the restless SN2009ip reveals the explosive ejection of

a massive stellar envelope

Distance of 24 Mpc

In the outskirts of NGC7259

Sub-solar metallicity environment 0.4<Z<0.9 Zsun

Discovery

Aug

2009

Outburst

Jul 2

010

Outburst

Sep

2010

OutburstM

ay 2

011

Oct

201

1

Explosion2

Explosion1

Aug

2012

Sep

2012

5 kpc

Now

Supern

ova

Imposto

r

Supern

ova ?

The complete story…

Eruptions

2012

SN2009ip eruptions plus 2012 double explosion

UV-Optical-NIR photometry

“Precursor bump” Major explosion

We know the story of eruptions of the progenitor in the previous years

The explosion has a luminous PRECURSOR

Detection of the PROGENITOR star in pre-explosion images (Smith+10, Foley+11): the progenitor is a massive star with M>60 Msun

Why is SN2009ip so interesting?

SN2009ip vs. a sample of SNe IIn and the peculiar explosion 1961V

VLACARMA 13-filter

photometry + spectra

UVOT &

HST

XMMXRT

BATFermi-LAT

Our observational campaign:

…no wavelength is left behind… The extensive monitoring is critical to: (i) constrain Erad, the temperature and radius of the emission; (ii)

constrain the role of different emission processes that dominate at different wavelengths.Understand the global properties of the explosion

Low-energy explosion: Erad~3d49 erg NOT powered by Nickel!

40 days

August 2012“shell ejection”

September 2012The shock breaks out through the dense thick shell ejected by the

first explosion

A second explosions happens

The general picture:

Mshell~0.1 Msun

Lx / Lopt < 10-4

Lbol/1d4

X-rays:they peak around the same time of the optical emission

…however:

As expected for a shock break out through a dense medium

Radio:Delayed peak due to free-free absorption

SN2009ip is a weak radio and X-ray emitter!

The metamorphosis in the optical:

BUT…

No sign of freshly synthesized material, yetSee e.g. [OI]

Low-res UVOT spectral campaign

HST

Oct 29

Nov 06

Super SED around the time of the optical peak

NIR excess of emission

NIR campaign: NIR excess:

t=tpk-4.5d

The NIR excess is not due to line emission

GeV photons and neutrinos from shock break-out

Predicted muon and anti-muon neutrino fluence from SN 2009ip using the observables and explosion

parameters according to the model by Murase et al. (2011). For this event, the atmospheric neutrino

background is more severe since SN 2009ip occurred in the southern hemisphere. For better localized

explosions, this plot shows how limits on the neutrino emission can be used to constrain the energy in

cosmic rays (ECR).

The collision of the ejecta with massive shells is expected to accelerate cosmic rays (CRs) and generate GeV gamma- rays (Murase et al. 2011; Katz et al. 2011) with fluence that depends both on the

explosion and on the environment parameters. We use the parameters inferred from the modeling of the optical-UV emission with shock break out, to predict the expected GeV fluence. Fermi-

LAT upper-limits are shown with black circles.

DENSE and compact SHELLM~0.1 Msun

(ejected by the 2012 precursor)

R~5d14 cm

R>4d15 cm

NIR emitting material

ejected during the previous

years outbursts

E~1d50 ergMej~0.5 Msun

The general picture is that of a massive star that repeatedly ejects massive shells of material on a time scale of years and less

Presence of a dominant time-scale common to eruption episodes and the major explosion, shared by completely independent events

40 days

-- Causal connection between precursor and main explosion-- “SIMPLE” mechanism-- Important channel for mass loss

What triggers the sudden shell ejection?This is not clear. However, two observational facts are crucial to our understanding:

Extreme similarity to SN2010mc, which implies:

Note: this NOT a claim for periodicity

Evolved massive stars have a much less boring life than expected: they suffer repetitive shell ejection on short time scales, whose physical origin is

not understood, questioning our current understanding of massive star evolution.

SN2009ip (and 10mc) might have just shown us a new channel for impulsive and sustained mass loss.

Smith 2010; Foley 2011; Fraser 2013; Levesque 2013; Mauerhan 2013; Ofek 2013; Pastorello 2013; Prieto 2012; Smith 2013; Soker 2013Ref in the literature:

Take-away message