The heart of Sakurai's object revealed by ALMA
Journal article, 2023

We present high-angular-resolution observations of Sakurai's object using the Atacama Large Millimeter Array, shedding new light on its morpho-kinematical structure. The millimetre continuum emission observed at an angular resolution of 20 milliarcsec (corresponding to 70 AU) reveals a bright compact central component whose spectral index indicates that it is composed of amorphous carbon dust. Based on these findings, we conclude that this emission traces the previously suggested dust disc observed in mid-infrared observations, and therefore our observations provide the first direct imaging of this disc. The H12CN(J = 4 → 3) line emission observed at an angular resolution of 300 milliarcsec (corresponding to 1000 AU) displays a bipolar structure with a north- south velocity gradient. From the position- velocity diagram of this emission, we identify the presence of an expanding disc and a bipolar molecular outflow. The inclination of the disc is determined to be i = 72. The derived values for the de-projected expansion velocity and the radius of the disc are vexp = 53 km s-1 and R = 277 AU, respectively. On the other hand, the de-projected expansion velocity of the bipolar outflow detected in the H12CN(J = 4 → 3) emission is of approximately 1000 km s-1. We propose that the molecular outflow has an hourglass morphology with an opening angle of around 60. Our observations unambiguously show that an equatorial disc and bipolar outflows formed in Sakurai's object during the 30 years following the occurrence of the born-again event, providing important constraints for future modelling efforts of this phenomenon.

Planetary nebulae: individual: Sakurai's object

Stars: low-mass

Binaries: general

Stars: winds

Planetary nebulae: general

Outflows

Author

Daniel Tafoya

Chalmers, Space, Earth and Environment, Onsala Space Observatory

P. A. M. van Hoof

Royal Observatory of Belgium

J. A. Toala

Universidad Nacional Autónoma de México

G. Van de Steene

Royal Observatory of Belgium

S. Randall

European Southern Observatory (ESO)

Ramlal Unnikrishnan Nair

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

S. Kimeswenger

Universidad Catolica del Norte

University of Innsbruck

M. Hajduk

University of Warmia and Mazury in Olsztyn

Daniela Barría

Universidad Central de Chile

A. Zijlstra

University of Manchester

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 677 L8

Onsala space observatory infrastructure

Swedish Research Council (VR) (2017-00648), 2018-01-01 -- 2021-12-31.

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.1051/0004-6361/202347293

More information

Latest update

9/26/2023