Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stellar desk in wave-like motion

08.10.2015

Astronomers detect unusual structures in AU Microscopii

As many other stars, AU Microscopii is surrounded by a dust disk. Now researchers – including scientists from the Max Planck Institute for Astronomy in Heidelberg – have discovered unusual structures in this disk, which change over time.


Images showing the debris disk around the star AU Mic in 2010 (top, Hubble Space Telescope), 2011 (center, ditto) and 2014 (bottom, SPHERE instrument), including newly discovered fast-moving wave-like features. The black central circles show where the brilliant light of the central star has been blocked off to reveal the much fainter disc, and the position of the star is indicated schematically. The scale bar at the top of the picture indicates the diameter of the orbit of the planet Neptune in the Solar System (60 times the distance Earth-Sun, corresponding to 60 AU). Note that the brightness of the outer parts of the disc has been artificially brightened to reveal the faint structure.

© ESO, NASA & ESA

The scientists are still puzzling what this phenomenon, which had previously never been observed before, could be. Is it connected with the eruptions of the star AU Mic? Or possibly even with as of yet undetected planets circling within the dust disk?

The star AU Mic ("AU Microscopii") in the Southern constellation Microscope, which is less than 33 light-years from Earth, is surrounded by a sizable disk made of dust, which observers on Earth can see directly edge-on.

Now, the has been imaged in great detail using SPHERE, the newly installed exoplanet-and-disks imaging machine at ESO's Very Large Telescope, and previous data from the Hubble Space Telescope. For the first time, astronomers could not only identify sub-structures, but also reliably track changes within the disk: fast-moving, wave-like features that move outwards within the disk.

When the instrument team for SPHERE chose targets for their initial observations, AU Mic was a natural candidate. MPIA director Thomas Henning, who is part of the team that studied the disk, explains: “Right away, we noticed detailed structures in the disk – if you had told me a few years ago that we would be able to image disks in such detail, I wouldn't have believed you. We compared these structures with images taken by a number of colleagues and myself using the Hubble Space Telescope in 2010 and 2011.”

Henning continues: “We were in for a surprise: Yes, we were able to identify reliably a considerable number of structures in both the SPHERE and the Hubble images. But within those few years, the features had moved away from the star. For the first time, we had observed not only the structure or the spectral features of a stellar debris disks – we were watching the disk change!”

According to a preliminary analysis, which will need to be confirmed by future observations, some of the matter observed might even be on its way out of the disk altogether, with sufficient speed to leave the stellar system behind.

There is, at this moment, no complete explanation for the disk dynamics observed by the combination of SPHERE and Hubble images. AU Mic, a red dwarf star (of type M1 Ve) a little over half the diameter of the Sun, is a rather young star with an age of around 12 million years, compared to our Sun's age of 5 billion years.

As is not uncommon for such young stars, AU Mic is very active, and frequently produces sizable flares: Eruptions involving the star's magnetic field, which catapult stellar plasma at high speed into the star's surroundings. It is possible that the moving features in the dust disk are caused by such stellar activity.

Another, tantalizing possibility is that the changes could be tell-tale signs of the presence of one or more giant planets in the debris disk. In that case, the motion would be due to disturbances caused by one or more planets' gravitational pull as it moves through the disk. So far, no planets around AU Mic have been detected – but this could change as search and imaging techniques improve.

In total, the surprising observations of disk changes around AU Mic provide for a whole programme of additional observations. If the researchers are very lucky, they might even be able to detect proto-planets – smaller bodies busily gathering sufficient mass for planethood – within the disk. More generally, extending observations such as these should allow for detailed comparison with simulations of such objects – and could shed light on processes of planet formation, which might have left tell-tale traces on the disk.

Contact

Dr. Markus Pössel
Press & Public Relations

Max Planck Institute for Astronomy, Heidelberg
Phone: +49 6221 528-261

Email: poessel@mpia.de


Prof. Dr. Thomas Henning
Max Planck Institute for Astronomy, Heidelberg
Phone: +49 6221 528-200

Fax:  +49 6221 528-339

Email: henning@mpia.de


Original publication
Boccaletti et al.
Fast-Moving Structures in the Debris Disk Around AU Microscopii
Nature, 8 October 2015

Dr. Markus Pössel | Max Planck Institute for Astronomy, Heidelberg

More articles from Physics and Astronomy:

nachricht Molecule flash mob
19.01.2017 | Technische Universität Wien

nachricht Magnetic moment of a single antiproton determined with greatest precision ever
19.01.2017 | Johannes Gutenberg-Universität Mainz

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>