ALMA observations of the nearby AGB star L${}_2$ Puppis. II. Gas disk properties derived from ${}^{12}$CO and ${}^{13}$CO $J=$3$-$2 emission

Abstract

The circumstellar environment of the AGB star L${}_2$ Puppis was observed with ALMA in cycle 3, with a resolution of $15\times 18\mathrm{mas}$. The molecular emission shows a differentially rotating disk, inclined to a nearly edge-on position. In the first paper in this series (paper I) the molecular emission was analysed to accurately deduce the motion of the gas in the equatorial regions of the disk. In this work we model the optically thick ${}^{12}$CO $J=$3$-$2 and the optically thin ${}^{13}$CO $J=$3$-$2 rotational transition to constrain the physical conditions in the disk. To realise this effort we make use of the 3D NLTE radiative transfer code {\tt LIME}. The temperature structure and velocity structure show a high degree of complexity, both radially and vertically. The radial H${}_2$ density profile in the disk plane is characterised by a power law with a slope of $-3.1$. We find a ${}^{12}$CO over ${}^{13}$CO abundance ratio of 10 inside the disk. Finally, estimations of the angular momentum in the disk surpass the expected available angular momentum of the star, strongly supporting the indirect detection of a compact binary companion reported in paper I. We estimate the mass of the companion to be around 1 Jupiter mass.

21 pages; 19 figures

References in corpus (14)

• Low-Mass Binary Induced Outflows from Asymptotic Giant Branch Stars
• Unexpectedly large mass loss during the thermal pulse cycle of the red giant R Sculptoris!
• Imaging the circumstellar envelopes of AGB stars
• Isolated vs. Common Envelope Dynamos in Planetary Nebula Progenitors
• ALMA observations of the nearby AGB star L2 Puppis - I. Mass of the central star and detection of a candidate planet
• Identifying close binary central stars of PN with Kepler
• Further ALMA observations and detailed modeling of the Red Rectangle
• Carbon and oxygen isotopic ratios for nearby miras
• CO/H2 Abundance Ratio ~ 10^{-4} in a Protoplanetary Disk
• A Massive Bipolar Outflow and a Dusty Torus with Large Grains in the Pre-Planetary Nebula IRAS 22036+5306
• Kepler detection of a new extreme planetary system orbiting the subdwarf-B pulsator KIC10001893
• An edge-on translucent dust disk around the nearest AGB star L2 Puppis - VLT/NACO spectro-imaging from 1.04 to 4.05 microns and VLTI interferometry
• A Model for the Formation of Large Circumbinary Disks Around Post AGB Stars
• The circumstellar disk of FS Tau B - A self-consistent model based on observations in the mid-infrared with NACO -

Cited by in corpus (10)

• (Sub)stellar companions shape the winds of evolved stars
• High-resolution observations of IRAS 08544-4431. Detection of a disk orbiting a post-AGB star and of a slow disk wind
• Pulsation-triggered dust production by asymptotic giant branch stars
• SPH modelling of companion-perturbed AGB outflows including a new morphology classification scheme
• Inner dusty envelope of the AGB stars W~Hydrae, SW\,Virginis, and R~Crateris using SPHERE/ZIMPOL
• Radio Stars: from kHz to THz
• Resolved imaging of the AR Puppis circumbinary disk
• Radiation-pressure-driven sub-Keplerian rotation of the disc around the AGB star L2 Pup
• Revealing new features of the millimetre emission of the circumbinary envelope of Mira Ceti
• Circumstellar CO J = 3-2 detected around the evolving metal-poor ([Fe/H] ~ -1.15 dex) AGB star RU Vulpeculae