PTF 10fqs: A LUMINOUS RED NOVA IN THE SPIRAL GALAXY MESSIER 99

Abstract

The Palomar Transient Factory (PTF) is systematically charting the optical transient and variable sky. A primary science driver of PTF is building a complete inventory of transients in the local Universe (distance less than 200 Mpc). Here, we report the discovery of PTF 10fqs, a transient in the luminosity "gap" between novae and supernovae. Located on a spiral arm of Messier 99, PTF 10fqs has a peak luminosity of M r = −12.3, red color (g − r = 1.0) and is slowly evolving (decayed by 1 mag in 68 days). It has a spectrum dominated by intermediate-width Hα (≈930 km s −1 ) and narrow calcium emission lines. The explosion signature (the light curve and spectra) is overall similar to that of M85 OT2006-1, SN 2008S, and NGC 300 OT. The origin of these events is shrouded in mystery and controversy (and in some cases, in dust). PTF 10fqs shows some evidence of a broad feature (around 8600Å) that may suggest very large velocities (≈10,000 km s −1 ) in this explosion. Ongoing surveys can be expected to find a few such events per year. Sensitive spectroscopy, infrared monitoring and statistics (e.g. disk versus bulge) will eventually make it possible for astronomers to unravel the nature of these mysterious explosions. Subject headings: stars: mass-loss -stars: AGB and post-AGB -supernovae: general -transients:individual (PTF 10fqs) 1 Unless explicitly noted, quoted magnitudes are in the R band 2

Common envelope evolution: where we stand and how we can move forward

“…The observed ejecta velocities also broadly match what might be expected from CEE (or a stellar merger). Kasliwal et al (2011) detected expansion velocities in PTF 10fqs of ∼1000 km s −1 . For NGC300 OT 2008 a wide range of velocities have been published, from ∼75 km s −1 (Bond et al 2009), to ∼1000 km s −1 (Berger et al 2009).…”

“…The energy involved in producing these events is order-ofmagnitude comparable to the likely orbital energy release from CEE or the binding energy of the envelope (about 10 47 erg, Bond et al 2009;Kulkarni et al 2007). Specific examples of this class include M85 OT 2006-1 Ofek et al 2008), NGC300 OT 2008 (Bond et al 2009; though see Kashi et al 2010 for an alternative scenario which involves rapid mass transfer from an extreme AGB star on its MS companion), PTF 10fqs (Kasliwal et al 2011) and M31 RV (Bond 2011, and references within). The rate of similar events has been estimated to be as much as 20 % of the core collapse SN rate ).…”

SPIRITS 15c and SPIRITS 14buu: Two Obscured Supernovae in the Nearby Star-forming Galaxy IC 2163

“…IR follow-up of optically discovered transients has revealed new classes of events that can be dominated by IR emission, especially at late times. At least two known classes of transients, with peak luminosities between those typical of novae and SNe, can develop IR-dominated spectral energy distributions (SEDs) as they evolve: (1) stellar mergers, or luminous red novae, e.g., M31-RV (Bond 2011, and references therein), V1309 Sco (Tylenda et al 2011), V838 Mon (Bond et al 2003;Sparks et al 2008), the 2011 transient in NGC4490 (hereafter NGC 4490-OT, Smith et al 2016) and M101OT2015-1 (M101-OT, Blagorodnova et al 2017), SN2008S-like events, or intermediate luminosity red transients (Prieto et al 2008; Thompson et al 2009;Kochanek 2011), also including NGC300OT2008-1 (hereafter NGC 300-OT, Bond et al 2009;Humphreys et al 2011) and PTF 10fqs (Kasliwal et al 2011). Furthermore, otherwise luminous optical sources such as SNe may suffer extinction from obscuring dust, lending themselves to discovery and follow-up at IR wavebands where the effect of dust extinction is significantly reduced.…”

Forming equatorial rings around dying stars

“…ILOTs are eruptive events with a typical decay time of weeks to years and with a peak luminosity between those of novae and supernovae (e.g. Bond et al 2009;Kashi & Soker 2010b;Kasliwal et al 2011;Tylenda et al 2013). Several studies in recent years pointed to some connections between different ILOTS, e.g, between NGC 300OT and pre-planetary nebulae (PNe) ), between NGC 300OT and the Great Eruption of η Car, (Kashi et al 2010), and between NGC 300OT and the PN NGC 6302 and the pre-PNs OH231.8+4.2, M1-92 and IRAS 22036+5306 (Soker & Kashi 2012).…”