Dying Sun-like stars leave whirlpools in their wake (Forwarded)

Royal Astronomical Society
London, U.K.

Issued by RAS Press Officers:

Robert Massey
Tel: +44 (0)20 7734 4582
AND
Anita Heward
Tel: +44 (0)1483 420 904

NATIONAL ASTRONOMY MEETING PRESS ROOM (16 - 20 APRIL ONLY):
Tel: +44 (0)1772 892 613
+44 (0)1772 892 475
+44 (0)1772 892 477

RAS Web site:
http://www.ras.org.uk/

RAS National Astronomy Meeting web site:
http://nam2007.uclan.ac.uk

CONTACT DETAILS ARE LISTED AT THE END OF THIS RELEASE.

PRESS INFORMATION NOTE: RAS PN 07/14 (NAM 10)

EMBARGOED FOR 00:01 BST, TUESDAY 17 APRIL 2007

DYING SUN-LIKE STARS LEAVE WHIRLPOOLS IN THEIR WAKE

Astronomers based at Jodrell Bank Observatory have found evidence that giant
whirlpools form in the wake of stars as they move through clouds in
interstellar space. The discovery will be presented by Dr Chris Wareing at
the Royal Astronomical Society's National Astronomy Meeting in Preston on
17th April.

Dr Wareing and his colleagues used the COBRA supercomputer to simulate in
three-dimensions the movement of a dying star through surrounding
interstellar gas. At the end of their life, Sun-sized stars lose their grip
on their outer layers and as much as half of their mass drifts off into
space. The computer simulation modelled the collision between material given
off by the star and the interstellar gas. It showed that a shockwave forms
ahead of the dying star and giant eddies and whirlpools develop in the tail
of material behind the star, similar to those seen in the wake of boats on
open water. The group have now backed up these predictions with observations
of the planetary nebula Sharpless 2-188 taken as part of the IPHAS (Isaac
Newton Telescope Photometric H alpha Survey of the Northern Galactic Plane).

The central star of Sharpless 2-188 is 850 light years away and it is
travelling at 125 kilometres per second across the sky. Observations show a
strong brightening in the direction in which the star is moving and faint
material stretching away in the opposite direction. Dr Wareing believes that
the bright structures in the arc observed ahead of Sharpless 2-188 are the
bowshock instabilities revealed in his simulations, which will form
whirlpools as they spiral past the star downstream to the tail.

"These vortices can improve the mixing of the stellar material back into
interstellar space, benefiting the next cycle of star formation. The
turbulent whirlpools have an inherent spin, or angular momentum, which is an
essential ingredient for the formation of the next generation of stars."
said Dr Wareing who developed the computer model during his PhD and is now
using it to understand the fate of our Sun.

Dying stars eject both gas and dust into space. The dust will coalesce into
planets around later generations of stars. The gas contains carbon,
necessary for life and produced inside stars. How the carbon, other gas and
dust are ejected from the dying star is not well understood. The whirlpools
in space can play an important role in mixing these essential ingredients
into the interstellar gas from which further stars and planets will form.

FURTHER INFORMATION

IPHAS
http://www.iphas.org/

IPHAS is a major survey of the Northern Galactic Plane being carried out
with the 2.5-metre Isaac Newton Telescope (INT) in La Palma. The IPHAS
survey began taking data with the INT Wide Field Camera in 2003 with the
goal of imaging the entire northern galactic plane in the latitude range -5
degrees b +5 degrees. Imaging of this 1800 sq. degree area should be
completed by the end of 2007.

NOTES FOR EDITORS

Royal Astronomical Society's National Astronomy Meeting
http://www.nam2007.uclan.ac.uk/info.php

The RAS National Astronomy Meeting is the UK's premier meeting for the
astronomy, solar system and space science communities. The RAS-NAM 2007 is
hosted by the University of Central Lancashire and is joined by the UK Solar
Physics and Spring MIST meetings. It is sponsored by the Royal Astronomical
Society, the UK Science and Technology Facilities Council and the University
of Central Lancashire.

Jodrell Bank Observatory

The Jodrell Bank Observatory is part of the School of Physics and Astronomy
at The University of Manchester. The Observatory is home to the Lovell Radio
Telescope and the MERLIN/VLBI National Facility which is operated by the
University on behalf of Science and Technology Facilities Council. 2007 is
the 50th Anniversary of the Lovell Space Telescope.

IMAGES:

1) Sharpless 2-188, taken from the IPHAS survey.

2) A detail of the bright arc of Sharpless 2-188.

3) A still from the computer simulation revealing the vortex moving
downstream.

All three images are available at different resolutions at:
http://www.jb.man.ac.uk/~cwareing/sh2188.html

MOVIES:

This movie is created from slices through the computer simulation revealing
the nature of the vortex. The simulation is performed in the frame of
reference of the star and the interstellar gas is flowing in from the top of
the movie box.

The movie is available at:
http://www.jb.man.ac.uk/~cwareing/sh2188.html

CONTACT INFORMATION:

This work was carried out by Dr Chris Wareing and collaborators as part of
his STFC-funded Ph.D. project at Jodrell Bank under the supervision of Dr
Tim O'Brien and as part of current post-doctoral research position at the
University of Manchester.

Dr Chris Wareing is also the North West of England's Regional Co-ordinator
for the Royal Institution's Science for Schools programme.

Dr Chris Wareing
School of Physics and Astronomy
The University of Manchester
Campus North
P.O. Box 88
Manchester
M60 1QD
Tel: +44 (0) 7880 806 416
Web: http://www.jb.man.ac.uk/~cwareing

From Monday 16th to Tuesday 17th April, Dr Wareing can be contacted via the
NAM Press Office (see details at top).

IPHAS: Principal Investigator and primary contact
Professor Janet Drew
Blackett Laboratory
Imperial College London
Exhibition Road
London
SW7 2AZ
Tel: 0044 (0) 207 594 7553
Fax: 0044 (0) 207 594 7541
Web: http://astro.ic.ac.uk/Research/Halpha/North/index.shtml