Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Dwarf that Carries a World

01.12.2005


HARPS Instrument Finds Neptune-Mass Exoplanet Around Small Star

A team of French and Swiss astronomers [1] have discovered one of the lightest exoplanets ever found using the HARPS instrument [2] on ESO’s 3.6-m telescope at La Silla (Chile). The new planet orbits a star belonging to the class of red dwarfs. As these stars are very common, this discovery proves crucial in the census of other planetary systems.

"Our finding possibly means that planets are rather frequent around the smallest stars," says Xavier Delfosse, from the Laboratoire d’Astrophysique de Grenoble (France) and co-author of the paper relating the work. "It certainly tells us that red dwarfs are ideal targets for the search for exoplanets."



The host star, Gl 581 [3], is located 20.5 light-years away in the Libra constellation (The Scales), and has a mass of only one third the mass of the Sun. Such red dwarfs are at least 50 times fainter than the Sun and are the most common stars in our Galaxy: among the 100 closest stars to the Sun, 80 belong to this class.

Being so numerous in our vicinity, it is thus fundamental to know if such stars also harbour planets. Previous surveys were rather unsuccessful: observations of about 200 red dwarfs revealed only 2 with planets.

"But previous surveys may have missed many planets due to their insufficient precision," says Stéphane Udry, from the Geneva Observatory and co-author of the work. "This is why we decided to make use of the ultra-precise, second generation, HARPS spectrograph. Our new result indicates this was the right strategy."

The newly found planet is about 17 times the Earth’s mass, or about the mass of Neptune. It is therefore one of the smallest ever found [4]. It is rather close to its host star and completes a full circle in only 5.4 days: the mean distance is about 6 million kilometres. By comparison, Mercury, the closest planet to the Sun, is at a distance of 58 million kilometres and completes an orbit in 88 days. Being so close, this alien world must be very hot, about 150 degrees.

The planet was revealed by the wobble it induces on the host star. With the HARPS very precise measurements, the astronomers found the star to move back and forth with a maximum velocity of 13 metres/second, or a little bit less than 50 km/h.

[1]: The team is composed of Xavier Bonfils (Laboratoire d’Astrophysique de Grenoble (LAOG), France, and Geneva Observatory, Switzerland), Thierry Forveille (CFHT Corporation, Hawaii, USA and LAOG), Xavier Delfosse and Christian Perrier (LAOG), Stéphane Udry, Michel Mayor, Francesco Pepe, and Didier Queloz (Geneva Observatory), François Bouchy (Laboratoire d’Astrophysique de Marseille, France), and Jean-Louis Bertaux (Service d’Aéronomie du CNRS, France).

[2]: HARPS (High Accuracy Radial Velocity for Planetary Searches) is the most precise spectrograph to date, measuring radial velocities with a precision better than 1 m/s, or 3.6 km/h.

[3]: Gl 581, or Gliese 581, is the 581th entry in the Gliese Catalogue, which lists all known stars within 25 parsecs (81.5 light years) of the Sun. It was originally compiled by Gliese and published in 1969, and later updated by Gliese and Jahreiss in 1991.

[4]: Of the 170 exoplanets known today, 5 are possibly less massive than the one orbiting Gl 581: Gliese 876d (7.3 Earth’s masses, or 7.3 ME), HD 160691 d (14 ME), 55 Cnc e (14.4 ME), HD 212301 b (14.4 ME) and HD 4308 b (15 ME). The masses indicated are in fact minimum masses, as the inclination of the system is unknown. One Jupiter mass is 18.6 Neptune masses or 319 Earth masses.

Henri Boffin | alfa
Further information:
http://www.eso.org/outreach/press-rel/pr-2005/pr-30-05.html

More articles from Physics and Astronomy:

nachricht Solar wind impacts on giant 'space hurricanes' may affect satellite safety
19.09.2017 | Embry-Riddle Aeronautical University

nachricht Integrated lasers on different surfaces
19.09.2017 | The Agency for Science, Technology and Research (A*STAR)

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: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

Im Focus: Artificial Enzymes for Hydrogen Conversion

Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.

Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

IVAM’s LaserForum visits the Swiss canton of St. Gallen with the topic ultrashort pulse lasers

06.09.2017 | Event News

 
Latest News

The Wadden Sea and the Elbe Studied with Zeppelin, Drones and Research Ships

19.09.2017 | Earth Sciences

Digging sensors out of an efficiency hole

19.09.2017 | Materials Sciences

Solar wind impacts on giant 'space hurricanes' may affect satellite safety

19.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>