Where is the nearest planet outside our solar system?
Question:
Answer:
Bellerophon, as it is sometimes referred to, around 51 Pegasi was the first exoplanet to be discovered around a Main Sequence star but it is not the nearest;
Epsilon Eridani b is the nearest and it is 10.5 light years away.
Epsilon Eridani (ε Eri / ε Eridani) is a notable main-sequence K2 class star in the constellation of Eridanus.
Epsilon Eridani is the third closest star outside of the solar system (after Alpha Centauri A and Sirius A) visible without a telescope. It has 85% of the Sun's mass, is roughly the same size, but has only 28% of its luminosity, and is 10.522 light years distant.
Epsilon Eridani's most unusual characteristic is its extremely variable spectrum, with many emission lines. Furthermore, it has a very strong magnetic field and has been measured to rotate once every 12 days (roughly twice as fast as the Sun). The reason for this is its youth; it is only about half a billion years old. Despite this young age, however, it has relatively low metallicity, particularly in iron.
Epsilon Eridani b is an extrasolar planet candidate around Epsilon Eridani, announced in 2000 by a team led by Artie Hatzes. The discoverers gave its mass as 1.2 ± 0.33 times that of Jupiter, with a mean distance of 3.3 AU from the star. The object's orbit is highly eccentric.
Other observers, including Geoffrey Marcy required more information on the star's doppler noise behaviour created by its large and varying magnetic field, and the discovery remains controversial.
Its existence had also been previously suspected by a Canadian team led by Bruce Campbell and Gordon Walker in the early 1990s, but their observations weren't definitive enough to make a solid discovery.
Observations by the Hubble Space Telescope have confirmed the existence of this planet. The estimated mass is 1.5 times Jupiter's mass, and the orbit is inclined by an angle of 30° from our line of sight. This orbital inclination is parallel to the observed dust ring around the star. The planet is expected to reach periapsis in 2007, when it could potentially be observed by the Hubble telescope.[
ASSESSMENT
However low metallicity means chances of a terrestrial (rocky) planet and organic chemicals and life developing on it are slim. If there were such a planet in the Epsilon Eridani system, it would have to be within 0.53 AU of the star to be in the habitable zone as regards liquid water and the right temperature range anyway, given the star is smaller than the Sun.
The "highly eccentric" orbit of fhe known planet would make a stable temperature range problematical on it, in any case.
As mankind cannot grow trees and plants on a gas giant (indeed cannot live on the surface of one) it is hard to see how we can terraform its atmosphere to a breathable one. The gravity is sufficient to retain an atmosphere but the wrong sort!
Of the 209 exoplanets found to date the vast majority are gas giants, simply because they are the easiest ones to spot, with current techniques.
The one good thing this star has got going for it is its youthfulness. If we did decamp there we would be able to stay for 8-9 billion years or so. But if it is not ideal in the first place, would we want to?
Tau Ceti (11.89 light years away) is known to have an asteroid belt and Gliese 876 (15 light years away) is the nearest star with a multi-planet system (it has three, one is less than half the size of Neptune).
I think it's a giant,hot planet in orbit around 51 Pegasi,about 50 light years away,but anyway,it's the first one that was spotted in 1995.
With the european space telescope COROT that was placed in orbit last week,we will be able to spot smaller,earth size planets in nearer stars.
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