Rings and filaments: The remarkable detached CO shell of U Antliae

Author(s)

Franz Kerschbaum, Matthias Maercker, Magdalena Brunner, Marko Mecina, Claudia Paladini, M Lindqvist, H. Olofsson, Elvire De Beck, Martin A. T. Groenewegen, E. Lagadec, Shazrene Mohamed, Sofia Ramstedt, Wouter H. T. Vlemmings, Markus Wittkowski

Abstract

Aims. Our goal is to characterize the intermediate age, detached shell carbon star U Antliae morphologically and physically in order to study the mass-loss evolution after a possible thermal pulse. Methods. High spatial resolution ALMA observations of unprecedented quality in thermal CO lines allow us to derive first critical spatial and temporal scales and constrain modeling efforts to estimate mass-loss rates for both the present day as well as the ejection period of the detached shell. Results. The detached shell is remarkably thin, overall spherically symmetric, and shows a barely resolved filamentary substructure possibly caused by instabilities in the interaction zone of winds with different outflow velocities. The expansion age of the detached shell is of the order of 2700 yr and its overall width indicates a high expansion-velocity and high mass-loss period of only a few hundred years at an average mass-loss rate of â‰ 10

^-5 M

_· yr

^-1. The post-high-mass-loss-rate-epoch evolution of U Ant shows a significant decline to a substantially lower gas expansion velocity and a mass-loss rate amounting to 4 × 10

^-8 M

_· yr

^-1, at present being consistent with evolutionary changes as predicted for the period between thermal pulses.

Organisation(s)

Department of Astrophysics

External organisation(s)

Chalmers University of Technology, Université Libre de Bruxelles, University of Cape Town, National Institute for Theoretical Physics, Royal Observatory of Belgium, Université Côte d'Azur, South African Astronomical Observatory (SAAO), Uppsala University, European Southern Observatory (Germany)

Journal

Astronomy & Astrophysics

Volume

605

No. of pages

8

ISSN

0004-6361

DOI

https://doi.org/10.1051/0004-6361/201730665

Publication date

09-2017

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/f5e7b5ad-87f2-4a47-b081-6abc6cb5312b

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