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

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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