Millimetre polarization of the protoplanetary nebula OH 231.8+4.2: a follow-up study with CARMA

Abstract

In order to investigate the characteristics and influence of the magnetic field in evolved stars, we performed a follow-up investigation of our previous submillimeter analysis of the proto-planetary nebula (PPN) OH 231.8+4.2 (Sabin et al. 2014), this time at 1.3 mm with the CARMA facility in polarisation mode for the purpose of a multi-scale analysis. OH 231.8+4.2 was observed at ∼ 2.5 ′′ resolution and we detected polarised emission above the 3σ threshold (with a mean polarisation fraction of 3.5%). The polarisation map indicates an overall organised magnetic field within the nebula. The main finding in this paper is the presence of a structure mostly compatible with an ordered toroidal component that is aligned with the PPN's dark lane. We also present some alternative magnetic field configuration to explain the structure observed. These data complete our previous SMA submillimeter data for a better investigation and understanding of the magnetic field structure in OH 231.8+4.2.

Bipolar planetary nebulae from common envelope evolution of binary stars

“…Bipolar PNe are often observed to consist of two main components (Sahai & Trauger 1998): a toroidal structure of slowly expanding gas (≈ 20 km s −1 ) and a perpendicular, fast bipolar (sometimes jet-like) outflow (≈ 70 km s −1 , in many cases exceeding 100 km s −1 , see Imai et al 2002;Tafoya et al 2020;Guerrero et al 2020). Magnetic fields have been inferred in such bipolar outflows, e.g., from synchrotron emission (Perez-Sanchez et al 2013), dust continuum polarization (Sabin et al 2015) and maser emission (Miranda et al 2001), and are thought to help collimate them (Vlemmings et al 2006). The lowvelocity component has been associated with the common envelope (CE) of a binary stellar system that is ejected preferentially into the region around its orbital plane.…”

The 1.3mm Full-Stokes Polarization System at CARMA

“…CARMA is an 23-antenna aperture synthesis telescope; the 1.3 mm receivers are installed on the six 10 m-diameter and nine 6 m-diameter antennas. The CARMA system makes it possible to observe the polarized thermal emission from dust in protostellar cores with angular resolutions of 1-2 00 , allowing one to study the magnetic¯eld morphologies on scales of $1000 AU in the nearest star-forming regions Krumholz et al, 2013;Stephens et al, 2013Stephens et al, , 2014Davidson et al, 2014;Wright et al, 2014;Segura-Cox et al, 2015) or toward evolved stars (Sabin et al, 2015). The CARMA polarization system also has been used to measure Faraday rotation toward the active galactic nucleus in 3C84 , constraining the mode of accretion onto the black hole in this source, and in Very Long Baseline Interferometer experiments that promise to probe the event horizons of nearby black holes (Johnson et al, 2014).…”

“…The CARMA system makes it possible to observe the polarized thermal emission from dust in protostellar cores with angular resolutions of 1-2 , allowing one to study the magnetic field morphologies on scales of ∼ 1000 AU in the nearest star-forming regions (Hull et al 2013;Krumholz et al 2013;Stephens et al 2013;Hull et al 2014;Davidson et al 2014;Wright et al 2014;Stephens et al 2014;Segura-Cox et al 2015) or toward evolved stars (Sabin et al 2015). The CARMA polarization system also has been used to measure Faraday rotation toward the active galactic nucleus in 3C84 (Plambeck et al 2014), constraining the mode of accretion onto the black hole in this source, and in Very Long Baseline Interferometer experiments that Electronic address: chat.hull@cfa.harvard.edu 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA 2 C.L.H.H.…”

Post-AGB nebular studies

“…Leal-Ferreira et al(2012) confirmed the presence of a magnetic field around OH231.8+4.2, and measured its strength within a few tens of AU of the binary system, but were not able to determine the morphology of the field. This was done by Sabin et al(2015) with CARMA observation that showed polarisation maps indicating an overall organised magnetic field within the nebula, with a toroidal component aligned with the central equatorial over-density. This seems to indicate the presence of a magnetic launching mechanism in the Rotten Egg Nebula.…”