What is the closest known planet to our Solar System?
Question:
Answer:
Epsilon Eridani b.
Epsilon Eridani a is the star itself, which is in the constellation Eridanus and the 13th nearest Star to us, at 10.5 ± 0.03 light years away and has an apparent magnitude of 3,73 and is of spectral type K2V.
It is the third closest star outside of the solar system visible without a telescope. It has 85% of the Sun's mass, almost that much of its diameter, and 28% of its luminosity.
Eridanus is the 6th largest of the 88 constellations and contains 4 stars brighter than Epsilon Eridani:
(α Eri) 0.45 Achernar
(67/β Eri) 2.78 Cursa
(34/γ Eri) 2.97 Zaurak
(23/δ Eri) 3.52 Rana
Achernar is 140 light years away and the 8th brightest star in the sky, only marginally brighter than Betelgeuse. As such, it is easily found and can help the amateur astronomer find Epsilon Eridani,
In the fictional Star Trek universe, Epsilon Eridani is considered by some fans to be the location of the planet Vulcan, the home of Mr. Spock.
Epsilon Eridani b is a 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.
THE NEXT NEAREST STAR WITH A PLANET
Is Gliese 876 which has three.
Gliese 876 a is the star itself, which is in the constellation Aquarius and the 54th nearest Star to us, at 15.3 ± 0.1 light years away and has an apparent magnitude of 10.18 (not visible to the unaided eye) and is of spectral type M3.5V.
Gliese 876 is a red dwarf star located in the constellation Aquarius. As of 2006 the star is known to host three extrasolar planets, including one with a mass less than half that of Neptune.
In 1998 an extrasolar planet was announced in orbit around Gliese 876 by two independent teams led by Geoffrey Marcy and Xavier Delfosse. The planet was designated Gliese 876 b and was detected by making measurements of the star's radial velocity as the planet's gravity pulled it around. The planet, around twice the mass of Jupiter, revolves around its star in an orbit taking approximately 61 days to complete, at a distance of only 0.208 AU, less than the distance from the Sun to Mercury.
In 2001 a second planet was detected in the system, inside the orbit of the previously-discovered planet. The 0.62 Jupiter-mass planet, designated Gliese 876 c is in a 1:2 orbital resonance with the outer planet, taking 30.340 days to orbit the star. The two planets undergo strong gravitational interactions as they orbit the star, causing the orbital elements to change rapidly.
In 2005, further observations by a team led by Eugenio Rivera revealed a third planet in the system, inside the orbits of the two Jupiter-size planets. The planet, designated Gliese 876 d, has a minimum mass only 5.88 times that of the Earth and may be a terrestrial planet.
Both of the system's Jupiter-mass planets are located in the habitable zone of Gliese 876, which extends between 0.116 to 0.227 AU from the star. This leaves no room for an additional habitable Earth-size planet in the system. On the other hand, large moons of the gas giants, if they exist, may be able to support life.
AND FINALLY THERE IS BARNARD'S STAR
Barnard's star is in the constellation Ophiuchus and the 4th nearest Star to us, at 5.96 ± 0.01 light years away and has an apparent magnitude of 9,57 and is of spectral type M4V.
It too is a red dwarf and invisible to the unaided eye It is the 4th closest star to us. Only the 3 stars of the Alpha & Proxima Centauri system are nearer, Interestingly though Barnard's Star is heading towards us at a proverbial rate of knots and by 11,800 AD will be only 3,8 light years away and it will then be our nearest neighbour.
Supposed planets
For many years from 1963 onwards, a substantial number of astronomers accepted a claim by Peter van de Kamp that he had detected a perturbation in the proper motion of Barnard's star consistent with its having one or more planets comparable in mass with Jupiter.
When independent data were collected in the 1980s, this conclusion came to be disputed and the consensus is now that van de Kamp's claim was erroneous. During the period that the claim was accorded credibility, it contributed to the star's fame among the science fiction community and the star's adoption as a target for Project Daedalus (The British Interplanetary Society's proposal for an interstellar space probe).
According to the h2g2 site "It is thought that Barnard's Star may have two planets each of about two-thirds the mass of Jupiter." If so, how very convenient for them to get nearer to us so we can take a closer look.
It's 10 light years away, but has no 'name', just a designation.
Xena. That one hasn't been officially made part of the solar system yet. It's only a couple of hundred light-years farther out than Pluto, much closer than any other star.
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