Volume 500, Number 2, June III 2009
|Page(s)||827 - 831|
|Section||Interstellar and circumstellar matter|
|Published online||29 April 2009|
A high-speed bipolar outflow from the archetypical pulsating star Mira A
Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester, M13 9PL, UK e-mail: firstname.lastname@example.org, Myfanwy.Lloyd@manchester.ac.uk
2 Instituto de Astronomia, UNAM, Apdo. Postal 877, Ensenada, B.C. 22800, Mexico e-mail: email@example.com
3 Institute of Astronomy & Astrophysics, National Observatory of Athens, I. Metaxa & V. Pavlou, P. Penteli, 15236 Athens, Greece e-mail: firstname.lastname@example.org
4 Centre for Astronomy, National University of Ireland, Galway, University Road, Galway, Ireland e-mail: Matt.Redman@nuigalway.ie
Accepted: 12 March 2009
Optical images and high-dispersion spectra have been obtained of the ejected material surrounding the pulsating AGB star Mira A. The two streams of knots on either side of the star, found in far-ultraviolet (FUV) GALEX images, have now been imaged clearly in the light of Hα. Spatially resolved profiles of the same line reveal that the bulk of these knots form a bipolar outflow with radial velocity extremes of ±150 km s-1 with respect to the central star. The south stream is approaching and the north stream receding from the observer. A displacement away from Mira A between the position of one of the south-stream knots in the new Hα image and its position in the previous Palomar Observatory Sky Survey (POSS I) red plate was noted. If interpreted as a consequence of expansion proper motions, the bipolar outflow is tilted at 69° ± 15° to the plane of the sky, has an outflow velocity of 160 ± 10 km s-1 and is ≈1000 y old.
Key words: stars: circumstellar matter / stars: variables: general / stars: binaries: general / stars: individual: Mira
© ESO, 2009
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