HD 101584: circumstellar characteristics and evolutionary status
Journal article, 2019

Context. There is growing evidence that red giant evolution is often affected by an interplay with a nearby companion, in some cases taking the form of a common-envelope evolution. Aims. We have performed a study of the characteristics of the circumstellar environment of the binary object HD 101584, that provides information on a likely evolutionary scenario. Methods. We have obtained and analysed ALMA observations, complemented with observations using APEX, of a large number of molecular lines. An analysis of the spectral energy distribution has also been performed. Results. Emissions from 12 molecular species (not counting isotopologues) have been observed, and most of them mapped with angular resolutions in the range 0 ''.1-0 ''.6. Four circumstellar components are identified: (i) a central compact source of size approximate to 0 ''.15, (ii) an expanding equatorial density enhancement (a flattened density distribution in the plane of the orbit) of size approximate to 3 '', (iii) a bipolar high-velocity outflow (approximate to 150 km s(-1)), and (iv) an hourglass structure. The outflow is directed almost along the line of sight. There is evidence of a second bipolar outflow. The mass of the circumstellar gas is approximate to 0.5 [D/1 kpc](2) M-circle dot, about half of it lies in the equatorial density enhancement. The dust mass is approximate to 0.01 [D/1 kpc](2) M-circle dot, and a substantial fraction of this is in the form of large-sized, up to 1 mm, grains. The estimated kinetic age of the outflow is approximate to 770 [D/1 kpc] yr. The kinetic energy and the scalar momentum of the accelerated gas are estimated to be 7 x 10(45) [D/1 kpc](2) erg and 10(39) [D/1 kpc](2) g cm s(-1), respectively. Conclusions. We provide good evidence that the binary system HD 101584 is in a post-common-envelope-evolution phase, that ended before a stellar merger. Isotope ratios combined with stellar mass estimates suggest that the primary star's evolution was terminated already on the first red giant branch (RGB). Most of the energy required to drive the outflowing gas was probably released when material fell towards the companion.

stars: individual: HD101584

stars: AGB and post-AGB

circumstellar matter

radio lines: stars

binaries: close

Author

Hans Olofsson

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

Theo Khouri

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

Matthias Maercker

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

Per Bergman

Chalmers, Space, Earth and Environment, Onsala Space Observatory

L. Doan

Uppsala University

D. Tafoya

National Astronomical Observatory of Japan

Wouter Vlemmings

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

E. M. L. Humphreys

ESO

Michael Lindqvist

Chalmers, Space, Earth and Environment, Onsala Space Observatory, Onsala Space Observatory, Observation Support

L. Nyman

ESO

S. Ramstedt

Uppsala University

Astronomy and Astrophysics

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

Vol. 623 A153

Magnetic fields and the outflows during the formation and evolution of stars (OUTFLOWMAGN)

European Commission (FP7), 2014-05-01 -- 2019-04-30.

Subject Categories

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

Condensed Matter Physics

DOI

10.1051/0004-6361/201834897

More information

Latest update

11/14/2019