Space.com: Three Super-Earths Found Orbiting One Star
- HD 40307 is in Pictor, about halfway between Alpha Pictoris and Lambda Doradus (around the left side of a painting if there was a painting on the Easel), not far from the Dorado border, at 23 Gemini 35.
HD 181433, also mentioned in the article, is in Pavo, about halfway between Kappa and Mu Pavonis on the Peacock's behind (not its tail), at 11 Capricorn 44.
Both have been added to the Extrasolar Planets file in my copy of SolarFire (hopefully I can get an upgrade this year).
Mark A. Holmes
Three Super-Earths Found Orbiting One Star
By Jeanna Bryner
posted: 16 June 2008
09:37 am ET
A trio of planets called super-Earths has been spotted orbiting a sun-like star, astrophysicists announced today at an international conference in France.
Super-Earths are more massive than Earth but less massive than Uranus and Neptune. Spotting true Earth-sized planets is challenging with current technology, but the presence of super-Earths suggests finding a world like ours is just a matter of time, researchers say.
The team located the trio with the HARPS instrument on the European Southern Observatory's 3.6-meter telescope at La Silla, Chile. They inferred the existence of the planets by noting the worlds' gravitational affects on the parent star's orbit. This method is called the radial velocity, or wobble, technique.
In addition, HARPS astronomers have tallied about 45 new candidate planets with a mass below 30 Earth masses and an orbital period shorter than 50 days. The researchers say the deluge implies one out of every three sun-like stars harbors such planets.
The trio's host star, HD 40307, is slightly less massive than the sun, and is located 42 light-years away, toward the southern Doradus and Pictor constellations. (A light-year is the distance light travels in one year, or about 5.88 trillion miles — 9.46 trillion kilometers.)
"We have made very precise measurements of the velocity of the star HD 40307 over the last five years, which clearly reveal the presence of three planets," said team member Michel Mayor of the Geneva Observatory in Switzerland.
The smallest of the trio weighs in at 4.2 Earth masses and orbits HD 40307 every 4.3 Earth days, while the largest, with a mass 9.4 times that of Earth, has a 20.4-day orbit. The middleweight is 6.7 Earth masses and has a 9.6-day trek around the star.
Since Mayor's 1995 discovery of a planet around the star 51 Pegasi, astronomers have noted more than 270 extrasolar planets, mostly around solar-like stars. Most of these planets are gas giants called "hot-Jupiters." The researchers say about one out of every 14 stars outside our solar system harbors a hot-Jupiter.
A basketful of other new exoplanets also got the spotlight at the same international conference, where researchers focused on extra-solar super-Earths.
* A duo orbiting the star HD 181433: a super-Earth (7.5 Earth masses) that orbits its star every 9.5 days, and a Jupiter-like planet with a nearly three-year period.
* Two planets, a 22 Earth-mass planet having a period of four days, and a Saturn-like planet with a three-year period.
"It is most probable that there are many other planets present: not only super-Earth and Neptune-like planets with longer periods, but also Earth-like planets that we cannot detect yet," said team member Stephane Udry, also of the Geneva Observatory. "Add to it the Jupiter-like planets already known, and you may well arrive at the conclusion that planets are ubiquitous."
- 8 June 2008 00:40am Cardiff, Wales.
LONDON (AFP) - UFO enthusiasts got a boost Friday when Welsh police
confirmed that one of their helicopter crews had spotted an "unusual
aircraft" flying over Cardiff earlier this month. An investigation into
the sighting had been launched, they said.
The police clarification came after The Sun reported a UFO had "attacked"
a police helicopter, following it for several miles over the Bristol
Channel. "The pilot banked sharply to avoid being hit, then launched into
a high-speed pursuit. But he was forced to give up the chase as the
helicopter's fuel ran low -- and the UFO escaped," the tabloid reported.
The helicopter crew had described the object as "flying saucer-shaped and
circled by flashing lights," it added.
"Err... " not so, said the police.
"South Wales Police can confirm its air support unit sighted an unusual
aircraft. This was reported to the relevant authorities for their
investigation," police said in a brief statement, avoiding the use of the
term 'UFO', or unidentified flying object.
At the time of the incident, the helicopter with three men on board was
waiting to land at the St Athan RAF base near Cardiff. The sighting
reportedly took place at 00:40 am (23:40 GMT) on June 8.
South Wales Police denied there was a pursuit and indicated that the
helicopter crew was never in any danger.