The Strongly Interacting Binary Scenarios of the enigmatic Supernova iPTF14hls Technion Israel Institute of Technology Roni A. Gofman & Noam Soker

Peculiar properties of iPTF14hls: Argument: these scenarios are rare cases of strongly interacting binary systems 1. Slow light curve evolution Required Rare Possible Accompanying Prolonged Activity Critical Ingredient 2. At least 5 peaks in the light Binary Property Processes curve (see figure on the right) Circum-Stellar Ejecta-CSM Massive Interaction to eject Jets launch by the 3. Fast circumstellar matter Matter (CSM) collision equatorial CSM equatorial mass companion Rapidly rotating Rapidly rotating The companion Accretion disk and Magnetar iPTF14hls's peculiarity motivated neutron star pre-collapse core spins-up the core jets at explosion several scenarios, four of which Late accretion Rapidly rotating The companion Accretion disk and Fallback we list in the left column of the on to neutron star pre-collapse core spins-up the core jets at explosion table in Abstract & Summary Arcavi et al. 2017 - Energetic eruptions leading to a Common Envelope (1) Ejecting a Accretion of mass on The neutron star The neutron star ejects peculiar hydrogen-rich explosion of a massive star Jets Supernova massive envelope to a neutron star spirals-in down into equatorial mass and (CEJSN) and/or (2) late jets inside a red giant star the companion's core turns to a magnetar

Our Claim: Large amounts of angular momentum require Our new scenario: A neutron star (NS) with mass 푴퐍퐒 = ퟏ. ퟒ푴⊙ and radius 푹퐍퐒 = ퟏퟐ퐤퐦 strong binary interaction (see Abstract & Summary table) launches jets with terminal velocity equaling the escape velocity ⇓ From this we estimate the following: 훽 < 1, the jets Magnetar activity is preceded by jets Jets mass: carry some angular AND −1 퐸jets 푅NS 푀NS momentum, making 푀jets = 0.026 51 푀⊙ Assumption: the jets carry 휂 ≈ 0.1 Jets’ activity in the CEJSN is followed by a magnetar 8 × 10 erg 12km 1.4푀⊙ this scenario times the accreted mass consistent Accreted mass: Consider the double magnetar phases scenario proposed −1 −1 휂 퐸jets 푅NS 푀NS by Woosley (2018) that we summarize as: 푀acc = 0. 26 51 푀⊙ 0.1 8 × 10 erg 12km 1.4푀⊙ 풋 = 휷 푮푴푵푺푹푵푺: the specific angular Magnetic Filed Initial Rotational Energy momentum of the accreted mass is a st 15 51 1 magnetar phase 퐵1 ≈ 2 × 10 G 퐸1 = 2 − 15 × 10 erg Neutron star’s angular momentum at the end of the accretion fraction 훽 of the Keplerian value 3 1 − nd 13 51 −1 2 2 2 magnetar phase 퐵2 ≈ 4 × 10 G 퐸2 ≈ 0.6 × 10 erg 휂 퐸jets 푅 푀 Replacing the 퐽 = 푀 푗 ≈ 7.72 × 1048훽 NS NS erg s acc acc acc 0.1 8 × 1051erg 12km 1.4푀 ⊙ Requirement: The second phase NS first magnetar st We examine the possibility to replace the 1 magnetar 50 1 3 rotational energy: 퐸P = 6 × 10 erg , 1 −1 ퟓퟏ 2 2 phase with jets phase by jets with 푬퐣퐞퐭퐬 ≈ ퟖ × ퟏퟎ 퐞퐫퐠 (퐸1 − 퐸2 average) 휂 훼 2 퐸jets 퐸푝 푅NS 푀NS as in Woosley (2018) 훽 ≈ 0.15 51 50 0.1 0.3 8 × 10 erg 6 × 10 erg 12km 1.4푀⊙ is feasible Woosley 2018 - Models for the unusual supernova iPTF14hls