SKYVIEWS OCTOBER 15-16, 2012
PLANET DISCOVERED VERY CLOSE TO ALPHA CENTURI B
As darkness falls, Ophiuchus, the serpent bearer, is well up in the west, flanked by the divided halves of the serpent. None of their stars is bright, but Ophiuchus is large, so if you look up from the western horizon, you are looking right at it.
The Milky Way arches from northeast to southwest across autumn's evening skies. Embedded in its star clouds is Cygnus, the swan. Cygnus flies south along the Milky Way with outstretched wings. Its tail is marked by the constellation's brightest star, Deneb.
European researchers have detected a planet -- just slightly more massive than Earth -- orbiting very close to Alpha Centauri B, a sun-like star only 4.3 light-years from our Sun. Orbiting once every 3.2 days, the planet is not in the habitable zon
The star system closest to our own sun hosts a planet with roughly Earth's mass and may harbor other alien worlds as well, a new study reports.
Astronomers detected the alien planet around the sunlike star Alpha Centauri B, which is part of a three-star system just 4.3 light-years away from us. The newfound world is about as massive as Earth, but it's no Earth twin; its heat-blasted surface may be covered with molten rock, researchers said.
The mere existence of the planet, known as Alpha Centauri Bb, suggests that undiscovered worlds may lurk farther away from its star — perhaps in the habitable zone, that just-right range of distances where liquid water can exist.
"Most of the low-mass planets are in systems of two, three to six or seven planets, out to the habitable zone," study co-author Stephane Udry, of the Geneva Observatory, told reporters today (Oct. 16).
So the discovery "opens really good prospects for detecting planets in the habitable zone in a system that is very close to us," Udry added. "In that sense, this system is a landmark."
Alpha Centauri Bb zips around its star every 3.2 days, orbiting at a distance of just 3.6 million miles (6 million kilometers). For comparison, Earth orbits about 93 million miles, or 150 million km, from the sun.
Dumusque and his colleagues determined that Alpha Centauri Bb is about 13 percent more massive than Earth, suggesting it's a rocky world. In addition to being the closest known exoplanet, it's also the first planet with a mass similar to Earth ever found around a sunlike star, researchers said.
Alpha Centauri Bb's extreme closeness to its parent star probably gives the planet a surface temperature around 2,240 degrees Fahrenheit (1,227 degrees Celsius), making it unsuitable for life, researchers said.
"At this temperature, there is a lot of chance that the surface — if it's made of rock, for example — it's not solid, but it's more like lava," Dumusque told reporters today.
Even though it resides in a three-star system — consisting of close-orbiting Alpha Centauri A and Alpha Centauri B, along with the more distant Proxima Centauri — the newfound world's orbit is stable over the long haul, Laughlin said. So are orbits in Alpha Centauri B's habitable zone, he added.
Traffic Report on 16 October '12
Four objects reported inside ten LD
There are four objects reported passing inside ten lunar distances (LD) of Earth today. Inside Earth's Hill sphere, newly announced 2012 TQ146 comes its closest to our planet on this passage, reaching 3.05 LD at 2346 UTC.
Further out, intruder 2012 TC4 (risk-listed radar target) is outbound from 5.59 to 7.06 LD, 2012 TE79 is inbound from 6.88 to 5.96 LD, and 2012 TD79 comes inside ten LD, traveling from 12.24 to 9.75 LD.
On approach next, 2010 JK1 arrives inside ten LD on November 22nd.
This report was updated at 1844 UTC with new discovery 2012 TQ146 (MPEC). Today's first report was generated at 1516 UTC with follow-up in today's DOU MPEC for 2012 TE79, 2012 TD79, and departed 2012 TP20.
stardate.org, space.com, nasa.org, a/cc news, spaceweather.com, entry submitted by Tina Marie on October 16, 2012