Exoplanets large and small, hot and cold...

[Whitters]

-- The Dwarf that Carries a World
http://www.spaceref.com/news/viewpr.html?pid=18414

"A team of French and Swiss astronomers have discovered one of the lightest exoplanets ever
found using the HARPS instrument 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."

[Whitters]

An international team of astronomers has discovered a planet more similar to Earth than any found to date. This groundbreaking discovery of a new extra solar planet, or exoplanet has been made by scientists searching for Earth-like planets capable of supporting life.
The first details of this discovery are made in today's edition of Nature.

Full story:
http://www.esa.int/esaSC/SEMDJ3NZCIE_index_0.html

[Rick]

The Hubble Space Telescope has found circumstantial evidence for a Jupiter-sized orbiting nearby star, Beta Pictoris, in a new image showing two dust disks orbiting the star.

Scientists have speculated that what appeared to be a warp in the main disk of dust was in fact a second disk. Confirmation of its existence has sparked new speculation that there is at least one gas giant in the stellar system.

More: http://www.theregister.co.uk/2006/06/28/dusty_ring_planet/

[Rick]

Would-be galactic colonists got a boost this week when a paper in the journal Science suggested that Earth-like planets might be more common than previously thought.

Despite the fact that almost all of the extra-solar planets we have detected have been gas giants - often much bigger than Jupiter - research from the US suggests many of these extra-solar solar systems could also harbour smaller, rocky worlds like Earth.

More: http://www.theregister.co.uk/2006/09/08/earthlike_planets/

[Rick]

The Dwarf Carried Other Worlds Too!

Astronomers have discovered the most Earth-like planet outside our Solar System to date, an exoplanet with a radius only 50% larger than the Earth and capable of having liquid water. Using the ESO 3.6-m telescope, a team of Swiss, French and Portuguese scientists discovered a super-Earth about 5 times the mass of the Earth that orbits a red dwarf, already known to harbour a Neptune-mass planet. The astronomers have also strong evidence for the presence of a third planet with a mass about 8 Earth masses.

More: http://www.eso.org/outreach/press-rel/pr-2007/pr-22-07.html

[Rick]

Astronomers have discovered the biggest transiting exoplanet yet. Orbiting a fading star in the constellation of Hercules, planet TrES-4 is a whopping 70 per cent bigger than Jupiter.

To put these numbers in context, Jupiter is a mere 16 per cent (or so) bigger than Saturn, but is almost four times the mass. Although volume scales as the cube of the radius increases, as a planet gets heavier its increased gravity tends to collapse it inwards, and so the stepwise increase in mass is even steeper that you would expect.

More: http://www.theregister.co.uk/2007/08/07/planet_cork/

[Rick]

...and from the BBC: http://news.bbc.co.uk/2/hi/science/nature/6934603.stm

[Rick]

Planet-hunting boffins based in the UK have announced the discovery of three more spinning globes to add to the more than 200 extrasolar planets already known to science. The planets turned up during the Wide Area Search for Planets (WASP).

All are gas giants, roughly the size of Jupiter, and are orbiting their parent stars so tightly that they whip around them in a matter of days.

More: http://www.theregister.co.uk/2007/10/31/superwasp_planets/

[Rick]

Astronomers have spotted a fifth planet orbiting 55 Cancri, making the (relatively) nearby star the centre of the most populous extrasolar system to date, New Scientist reports.

55 Cancri lies 41 light years from Earth, and is "slightly cooler and dimmer than our own Sun". It was already known to boast four planets, three giants orbiting closer than Mercury is to the Sun, and a fourth at roughly Jupiter's distance from the Sun, but four times as massive as the former.

More: http://www.theregister.co.uk/2007/11/07/largest_extrasolar_system/

[Mike]

More than 10 years after the discovery of the first extra-solar planet, a European team of astronomers have confirmed that one of the planets might indeed be located within the habitable zone around the star Gliese 581.

Until a few years ago, most of the newly discovered exo-planets were Jupiter-mass, probably gaseous, planets. Recently, astronomers have announced the discovery of several planets that are potentially much smaller super-Earths with a minimum mass lower than 10 Earth masses.

In April, a European team announced in Astronomy & Astrophysics the discovery of two new planets orbiting the M star Gliese 581 (a red dwarf), with masses of at least 5 and 8 Earth masses. Given their distance to their parent star, these new planets -Gliese 581c and Gliese 581d- were the first ever possible candidates for habitable planets.

Continue reading here......... http://www.dailygalaxy.com/my_weblog/2007/12/return-to-earth.html

[mickw]

The discovery of a Jupiter-like planet and another about the size of Saturn has astronomers suggesting that solar systems like our own may be common.

The newfound worlds both appear to be gaseous and are about 80 percent the sizes of Jupiter and Saturn, the astronomers said today. They orbit a star that is about half the size of our sun and is dimmer and much cooler.

"This is the first discovery of a multi-planet system that could be analogous to our solar system," said research team member Alison Crocker, a Dartmouth College graduate now studying at Oxford University.

More:  http://news.yahoo.com/s/space/20080214/sc_space/solarsystemlikeoursfound

[mickw]

Astronomers have peered into the womb of a stellar disk to capture an image of material falling onto what could be a planet in an early stage of formation.
The new image shows a somewhat horseshoe-shaped void in the disk surrounding a young star called AB Aurigae. Within the void, a barely visible bright spot could indicate a developing object that's currently between 5 and 37 times the mass of Jupiter

More:  http://www.space.com/scienceastronomy/080326-planet-progress.html

[Rick]

An embryonic planet detected outside our Solar System could be less than 2,000 years old, astronomers say.

The ball of dust and gas, which is in the process of turning into a Jupiter-like giant, was detected around the star HL Tau, by a UK team.

Research leader Dr Jane Greaves said the planet's growth may have been kickstarted when another young star passed the system 1,600 years ago.

More: http://news.bbc.co.uk/2/hi/science/nature/7326318.stm

[Rick]

Astronomers have discovered a planetary system orbiting a distant star which looks much like our own.

They found two planets that were close matches for Jupiter and Saturn orbiting a star about half the size of our Sun.

Martin Dominik, from St Andrews University in the UK, said the finding suggested systems like our own could be much more common than we thought.

And he told a major meeting that astronomers were on the brink of finding many more of them.

More: http://news.bbc.co.uk/2/hi/science/nature/7333155.stm

[mickw]

Astronomers have discovered possibly the smallest extrasolar planet yet, a rocky world that's orbiting a star in the constellation Leo.
"After final confirmation, the new exoplanet will be the smallest found to date," said lead researcher Ignasi Ribas of the Spanish Research Council (CSIC). "The study opens a new path that should lead to the discovery of even smaller planets in the near future, with the goal of eventually finding worlds more and more similar to the Earth."

More:  http://www.space.com/scienceastronomy/080409-smallest-exoplanet.html