Andrew Yee[_1_]
January 20th 08, 02:27 AM
ESO Education and Public Relations Dept.
Contact
Uwe Wolter
Hamburg Observatory, Germany
Phone: +49 40 42891 4130
For Immediate Release: 19 December 2007
ESO Science Release 53/07
----------------------------------------------------------------------------
Text with all links and the photos are available on the ESO Website at URL:
http://www.eso.org/public/outreach/press-rel/pr-2007/pr-53-07.html
----------------------------------------------------------------------------
Speedy Mic's Photograph
Flare found on ultra-fast rotating star puzzles astronomers
Using observations from ESO's VLT, astronomers were able for the first time
to reconstruct the site of a flare on a solar-like star located 150 light
years away. The study of this young star, nicknamed 'Speedy Mic' because of
its fast rotation, will help scientists better understand the youth of our
Sun.
The astronomers [1] observed the star BO Microscopii [2] during two
consecutive nights in October 2006, simultaneously with the UVES
spectrograph on ESO's Very Large Telescope and ESA's XMM-Newton X-ray
satellite.
Using a technique called 'Doppler imaging' [3], the astronomers
reconstructed images of the surface of the star, detecting the presence of
several spots. A few are near the visible pole, while most spots are
asymmetrically distributed at mid-latitudes.
"The image we could secure of Speedy Mic is, given its distance, a real
achievement, that allows us to localise for the first time ever the source
of a flare and its surrounding," says Uwe Wolter, lead author of the paper
relating the discovery.
The X-ray observations indeed identified several flares, which are sudden
and vast releases of energy. For one of them, the astronomers could pinpoint
its origin on the surface of the star. The flare, lasting about 4 hours, was
a hundred times more energetic than a large solar flare and considerably
larger than solar coronal loops.
The surprising finding, the team says, was the location of the flare.
Contrary to our Sun, the site of the observed flare does not correspond to
the detected spots [4].
"Interestingly, the flare occurs on a rather inconspicuous portion of the
star's surface, away from the main concentration of activity in terms of
dark spots," explains Wolter.
Speedy Mic is a very young star: with an age of only about 30 million years,
it is roughly 150 times younger than the Sun. "It is very likely that our
young Sun was a fast rotator as well," says Wolter. "Studying Speedy Mic is
thus like observing our own host star while still in its infancy. These
studies may also contribute to the understanding of current solar eruptions
which can cause havoc in our telecommunications and power distributions."
The team reports their results in the journal Astronomy and Astrophysics
("Doppler imaging an X-ray flare on the ultrafast rotator BO Mic - A
contemporaneous multiwavelength study using XMM-Newton and VLT", by. U.
Wolter et al.).
Notes
[1] The team is composed of U. Wolter, J. Robrade, and J. Schmitt (Hamburg
Observatory, Germany), and J. Ness (Arizona State University, USA).
[2] BO Microscopii (or BO Mic and nicknamed 'Speedy Mic') is a young star
with a mass about 90 % the mass of our Sun. It is located 150 light years
away towards the Microscope constellation. Speedy Mic owns its name because
of its very fast rotation: it completes a full turn in about 9 hours. The
object rotates thus 66 times as fast as our Sun, which results in much
stronger magnetic fields than on the Sun.
[3] Speedy Mic is a star slightly smaller than the Sun and is about ten
million times further away from us than the Sun. Trying to see spots on its
surface is thus as challenging as trying to directly obtain a photograph of
the footsteps of Neil Armstrong on the Moon, and be able to see details in
it. This is impossible to achieve even with the best telescopes: to obtain
an image with such amount of details, you would need a telescope with a 400
km wide mirror! Astronomers make therefore use of indirect imaging
techniques, such as Doppler imaging, to achieve this incredible prowess.
Doppler imaging makes use of the information contained in the slightly
changing spectra observed as a star rotates. In this case, the astronomers
obtained 142 spectra of the star with the UVES spectrograph on ESO's VLT.
[4] Sunspots, which are cooler, but still very hot regions of the Sun's
surface, are known to be regions of intense magnetic activity.
National contacts for the media:
Belgium: Dr. Rodrigo Alvarez, +32-2-474 70 50
Czech Republic: Pavel Suchan, +420 267 103 040
Finland: Ms. Tiina Raivo, +358 9 7748 8369
Denmark: Dr. Michael Linden-Vornle, +45-33-18 19 97
France: Dr. Daniel Kunth, +33-1-44 32 80 85
Germany: Dr. Jakob Staude, +49-6221-528229
Italy: Dr. Leopoldo Benacchio, +39-347-230 26 51
The Netherlands: Ms. Marieke Baan, +31-20-525 74 80
Portugal: Prof. Teresa Lago, +351-22-089 833
Spain: Dr. Miguel Mas-Hesse, +34918131196
Sweden: Dr. Jesper Sollerman, +46-8-55 37 85 54
Switzerland: Dr. Martin Steinacher, +41-31-324 23 82
United Kingdom: Mr. Peter Barratt, +44-1793-44 20 25
USA: Dr. Paola Rebusco, +1-617-308-2397
----------------------------------------------------------------------------
ESO Press Information is available on Receive email notification
the WWW at about important news from
http://www.eso.org/outreach/press-rel/ ESO - subscribe to the
ESO-NEWS Mailing List.
----------------------------------------------------------------------------
Copyright ESO Education & Public Relations Department
Karl-Schwarzschild-Strasse 2, D-85748 Garching, Germany
----------------------------------------------------------------------------
Contact
Uwe Wolter
Hamburg Observatory, Germany
Phone: +49 40 42891 4130
For Immediate Release: 19 December 2007
ESO Science Release 53/07
----------------------------------------------------------------------------
Text with all links and the photos are available on the ESO Website at URL:
http://www.eso.org/public/outreach/press-rel/pr-2007/pr-53-07.html
----------------------------------------------------------------------------
Speedy Mic's Photograph
Flare found on ultra-fast rotating star puzzles astronomers
Using observations from ESO's VLT, astronomers were able for the first time
to reconstruct the site of a flare on a solar-like star located 150 light
years away. The study of this young star, nicknamed 'Speedy Mic' because of
its fast rotation, will help scientists better understand the youth of our
Sun.
The astronomers [1] observed the star BO Microscopii [2] during two
consecutive nights in October 2006, simultaneously with the UVES
spectrograph on ESO's Very Large Telescope and ESA's XMM-Newton X-ray
satellite.
Using a technique called 'Doppler imaging' [3], the astronomers
reconstructed images of the surface of the star, detecting the presence of
several spots. A few are near the visible pole, while most spots are
asymmetrically distributed at mid-latitudes.
"The image we could secure of Speedy Mic is, given its distance, a real
achievement, that allows us to localise for the first time ever the source
of a flare and its surrounding," says Uwe Wolter, lead author of the paper
relating the discovery.
The X-ray observations indeed identified several flares, which are sudden
and vast releases of energy. For one of them, the astronomers could pinpoint
its origin on the surface of the star. The flare, lasting about 4 hours, was
a hundred times more energetic than a large solar flare and considerably
larger than solar coronal loops.
The surprising finding, the team says, was the location of the flare.
Contrary to our Sun, the site of the observed flare does not correspond to
the detected spots [4].
"Interestingly, the flare occurs on a rather inconspicuous portion of the
star's surface, away from the main concentration of activity in terms of
dark spots," explains Wolter.
Speedy Mic is a very young star: with an age of only about 30 million years,
it is roughly 150 times younger than the Sun. "It is very likely that our
young Sun was a fast rotator as well," says Wolter. "Studying Speedy Mic is
thus like observing our own host star while still in its infancy. These
studies may also contribute to the understanding of current solar eruptions
which can cause havoc in our telecommunications and power distributions."
The team reports their results in the journal Astronomy and Astrophysics
("Doppler imaging an X-ray flare on the ultrafast rotator BO Mic - A
contemporaneous multiwavelength study using XMM-Newton and VLT", by. U.
Wolter et al.).
Notes
[1] The team is composed of U. Wolter, J. Robrade, and J. Schmitt (Hamburg
Observatory, Germany), and J. Ness (Arizona State University, USA).
[2] BO Microscopii (or BO Mic and nicknamed 'Speedy Mic') is a young star
with a mass about 90 % the mass of our Sun. It is located 150 light years
away towards the Microscope constellation. Speedy Mic owns its name because
of its very fast rotation: it completes a full turn in about 9 hours. The
object rotates thus 66 times as fast as our Sun, which results in much
stronger magnetic fields than on the Sun.
[3] Speedy Mic is a star slightly smaller than the Sun and is about ten
million times further away from us than the Sun. Trying to see spots on its
surface is thus as challenging as trying to directly obtain a photograph of
the footsteps of Neil Armstrong on the Moon, and be able to see details in
it. This is impossible to achieve even with the best telescopes: to obtain
an image with such amount of details, you would need a telescope with a 400
km wide mirror! Astronomers make therefore use of indirect imaging
techniques, such as Doppler imaging, to achieve this incredible prowess.
Doppler imaging makes use of the information contained in the slightly
changing spectra observed as a star rotates. In this case, the astronomers
obtained 142 spectra of the star with the UVES spectrograph on ESO's VLT.
[4] Sunspots, which are cooler, but still very hot regions of the Sun's
surface, are known to be regions of intense magnetic activity.
National contacts for the media:
Belgium: Dr. Rodrigo Alvarez, +32-2-474 70 50
Czech Republic: Pavel Suchan, +420 267 103 040
Finland: Ms. Tiina Raivo, +358 9 7748 8369
Denmark: Dr. Michael Linden-Vornle, +45-33-18 19 97
France: Dr. Daniel Kunth, +33-1-44 32 80 85
Germany: Dr. Jakob Staude, +49-6221-528229
Italy: Dr. Leopoldo Benacchio, +39-347-230 26 51
The Netherlands: Ms. Marieke Baan, +31-20-525 74 80
Portugal: Prof. Teresa Lago, +351-22-089 833
Spain: Dr. Miguel Mas-Hesse, +34918131196
Sweden: Dr. Jesper Sollerman, +46-8-55 37 85 54
Switzerland: Dr. Martin Steinacher, +41-31-324 23 82
United Kingdom: Mr. Peter Barratt, +44-1793-44 20 25
USA: Dr. Paola Rebusco, +1-617-308-2397
----------------------------------------------------------------------------
ESO Press Information is available on Receive email notification
the WWW at about important news from
http://www.eso.org/outreach/press-rel/ ESO - subscribe to the
ESO-NEWS Mailing List.
----------------------------------------------------------------------------
Copyright ESO Education & Public Relations Department
Karl-Schwarzschild-Strasse 2, D-85748 Garching, Germany
----------------------------------------------------------------------------