Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 
Datenbankrecherche:

 

Do missing Jupiters mean massive comet belts?

27.11.2012
Using ESA’s Herschel space observatory, astronomers have discovered vast comet belts surrounding two nearby planetary systems known to host only Earth-to-Neptune-mass worlds. The comet reservoirs could have delivered life-giving oceans to the innermost planets.
In a previous Herschel study, scientists found that the dusty belt surrounding nearby star Fomalhaut must be maintained by collisions between comets.

Debris disc around GJ 581


Debris disc around 61 Vir

In the new Herschel study, two more nearby planetary systems – GJ 581 and 61 Vir – have been found to host vast amounts of cometary debris.

Herschel detected the signatures of cold dust at 200ºC below freezing, in quantities that mean these systems must have at least 10 times more comets than in our own Solar System’s Kuiper Belt.

GJ 581, or Gliese 581, is a low-mass M dwarf star, the most common type of star in the Galaxy. Earlier studies have shown that it hosts at least four planets, including one that resides in the ‘Goldilocks Zone’ – the distance from the central sun where liquid surface water could exist.

Two planets are confirmed around G-type star 61 Vir, which is just a little less massive than our Sun.

The planets in both systems are known as ‘super-Earths’, covering a range of masses between 2 and 18 times that of Earth.

Interestingly, however, there is no evidence for giant Jupiter- or Saturn-mass planets in either system.

The gravitational interplay between Jupiter and Saturn in our own Solar System is thought to have been responsible for disrupting a once highly populated Kuiper Belt, sending a deluge of comets towards the inner planets in a cataclysmic event that lasted several million years.

“The new observations are giving us a clue: they’re saying that in the Solar System we have giant planets and a relatively sparse Kuiper Belt, but systems with only low-mass planets often have much denser Kuiper belts,” says Dr Mark Wyatt from the University of Cambridge, lead author of the paper focusing on the debris disc around 61 Vir.

“We think that may be because the absence of a Jupiter in the low-mass planet systems allows them to avoid a dramatic heavy bombardment event, and instead experience a gradual rain of comets over billions of years.”

“For an older star like GJ 581, which is at least two billion years old, enough time has elapsed for such a gradual rain of comets to deliver a sizable amount of water to the innermost planets, which is of particular importance for the planet residing in the star’s habitable zone,” adds Dr Jean-Francois Lestrade of the Observatoire de Paris who led the work on GJ 581.

However, in order to produce the vast amount of dust seen by Herschel, collisions between the comets are needed, which could be triggered by a Neptune-sized planet residing close to the disc.

“Simulations show us that the known close-in planets in each of these systems cannot do the job, but a similarly-sized planet located much further from the star – currently beyond the reach of current detection campaigns – would be able to stir the disc to make it dusty and observable,” says Dr Lestrade.

“Herschel is finding a correlation between the presence of massive debris discs and planetary systems with no Jupiter-class planets, which offers a clue to our understanding of how planetary systems form and evolve,” says Göran Pilbratt, ESA’s Herschel project scientist.

Markus Bauer | EurekAlert!
Further information:
http://www.esa.int
http://www.esa.int/SPECIALS/Herschel/SEMVDXDQZ9H_0.html

More articles from Physics and Astronomy:

nachricht Earthlike 'Star Wars' Tatooines May Be Common
31.03.2015 | University of Utah

nachricht Dusty substructure in a galaxy far far away
31.03.2015 | Max-Planck-Institut für Astrophysik

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: Smarte Fassaden mit Energiespareffekt

Gläserne Bürobauten gehören zu den großen Energiefressern. Sie müssen aufwändig klimatisiert werden. Ein von Fraunhofer-Forschern und Designern entwickeltes Fassadenelement für Glasfronten soll den Energieverbrauch senken. Dazu nutzt es die Wärmenergie der Sonne. Ein Demonstrator ist auf der Hannover Messe zu sehen.

Fast 40 Prozent beträgt der Anteil von Gebäuden am gesamten Energieverbrauch in Deutschland. Das Heizen, Kühlen und Lüften von Wohnhäusern, Büroimmobilien und...

Im Focus: Lizard activity levels can help scientists predict environmental change

Research study provides new tools to assess warming temperatures

Spring is here and ectotherms, or animals dependent on external sources to raise their body temperature, are becoming more active. Recent studies have shown...

Im Focus: Der Werkstoff macht’s: Nichtoxidkeramik eröffnet neue Perspektiven für den Chemie- und Anlagenbau

Herausragende chemische, thermische und tribologische Eigenschaften prädestinieren siliziuminfiltriertes Siliziumcarbid für die Produktion großvolumiger keramischer Bauteile.

Ein neuartiges Verfahren überwindet nun verfahrenstechnischen Grenzen konventioneller Formgebungsmethoden. Dadurch können  Komponenten mit großen...

Im Focus: Hannover Messe 2015: Saving energy with smart façades

Glass-fronted office buildings are some of the biggest energy consumers, and regulating their temperature is a big job. Now a façade element developed by Fraunhofer researchers and designers for glass fronts is to reduce energy consumption by harnessing solar thermal energy. A demonstrator version will be on display at Hannover Messe.

In Germany, buildings account for almost 40 percent of all energy usage. Heating, cooling and ventilating homes, offices and public spaces is expensive – and...

Im Focus: Nonoxide ceramics open up new perspectives for the chemical and plant engineering

Outstanding chemical, thermal and tribological properties predestine silicon carbide for the production of ceramic components of high volume. A novel method now overcomes the procedural and technical limitations of conventional design methods for the production of components with large differences in wall thickness and demanding undercuts.

Extremely hard as diamond, shrinking-free manufacturing, resistance to chemicals, wear and temperatures up to 1300 °C: Silicon carbide (SiSiC) bundles all...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics
Veranstaltungen

Holzbau mit Bestand - Thema der Norddeutschen Holzbautagung 2015

01.04.2015 | Veranstaltungen

Training für LNG-Anwender aus dem maritimen und nichtmaritimen Bereich

01.04.2015 | Veranstaltungen

Wie lässt sich Nachhaltigkeit messen und bewerten?

01.04.2015 | Veranstaltungen

 
B2B-VideoLinks
Weitere VideoLinks >>>
Aktuelle Beiträge

TU Dresden startet drei Forschungsprojekte zum regionalen Wasserressourcen-Management

01.04.2015 | Förderungen Preise

Lebensmittelvergiftungen: 18 neue Varianten eines Bakteriengifts entdeckt

01.04.2015 | Biowissenschaften Chemie

Verbrennungsmotoren aus Kunststoff

01.04.2015 | HANNOVER MESSE