'Speedy Mic's' photograph

December 19, 2007

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 prowess, 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.

"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 such a fast rotator as well," says Wolter. "Studying Speedy Mic is thus like observing our own host star while still in its infancy and so, better understand how the eruptions on the young Sun affected the planets. These studies may also contribute to the understanding of current solar eruptions which can cause havoc in our telecommunications and power distributions."

[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. The object rotates 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 is. 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.


Related Astronomers Articles from Brightsurf:

Astronomers are bulging with data
For the first time, over 250 million stars in our galaxy's bulge have been surveyed in near-ultraviolet, optical, and near-infrared light, opening the door for astronomers to reexamine key questions about the Milky Way's formation and history.

Astronomers capture a pulsar 'powering up'
A Monash-University-led collaboration has, for the first time, observed the full, 12-day process of material spiralling into a distant neutron star, triggering an X-ray outburst thousands of times brighter than our Sun.

Astronomers discover new class of cosmic explosions
Analysis of two cosmic explosions indicates to astronomers that the pair, along with a puzzling blast from 2018, constitute a new type of event, with similarities to some supernovae and gamma-ray bursts, but also with significant differences.

Astronomers discover planet that never was
What was thought to be an exoplanet in a nearby star system likely never existed in the first place, according to University of Arizona astronomers.

Canadian astronomers determine Earth's fingerprint
Two McGill University astronomers have assembled a 'fingerprint' for Earth, which could be used to identify a planet beyond our Solar System capable of supporting life.

Astronomers help wage war on cancer
Techniques developed by astronomers could help in the fight against breast and skin cancer.

Astronomers make history in a split second
In a world first, an Australian-led international team of astronomers has determined the precise location of a powerful one-off burst of cosmic radio waves.

Astronomers witness galaxy megamerger
Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international team of scientists has uncovered a startlingly dense concentration of 14 galaxies that are poised to merge, forming the core of what will eventually become a colossal galaxy cluster.

Astronomers discover a star that would not die
An international team of astronomers has made a bizarre discovery; a star that refuses to stop shining.

Astronomers spun up by galaxy-shape finding
For the first time astronomers have measured how a galaxy's spin affects its shape -- something scientists have tried to do for 90 years -- using a sample of 845 galaxies.

Read More: Astronomers News and Astronomers Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.