HD 190984 b
Encyclopedia
HD 190984 b is an extrasolar planet
which orbits the F-type main sequence
star
HD 190984
, located approximately 330 light years away in the constellation
Pavo
. This planet is at least three times more massive than Jupiter
and takes 13 years and four-and-a-half months to orbit the star at a semimajor axis of 5.5 AU
with an eccentricity
of 0.57. This planet was detected by HARPS on October 19, 2009, together with 29 other planets.
Since this is a very long-period planet detected by the radial velocity method that this planet didn't complete the orbit during the continuous observations, the error range for orbital period is very large, at 4885 ± 1600 days or 13.37 ± 4.4 years. This puts it in the range of semimajor axes between 4.2 and 6.6 AU or between 630 and 990 Gm. So this planet will need couple more years of observations to better constrain the period and semimajor axis.
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
which orbits the F-type main sequence
Main sequence
The main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...
star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
HD 190984
HD 190984
HD 190984 is a 9th magnitude F-type main sequence star located approximately 330 light years away in the constellation Pavo. This star is larger, hotter, brighter, and more massive than our Sun. Also its metal content is one-thirds as much as the Sun. In 2009, a gas giant planet was found in orbit...
, located approximately 330 light years away in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Pavo
Pavo (constellation)
Pavo is a constellation in the southern sky. Its name is Latin for peacock. It is one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35-cm diameter celestial globe published in 1597 in...
. This planet is at least three times more massive than Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
and takes 13 years and four-and-a-half months to orbit the star at a semimajor axis of 5.5 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
with an eccentricity
Orbital eccentricity
The orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...
of 0.57. This planet was detected by HARPS on October 19, 2009, together with 29 other planets.
Since this is a very long-period planet detected by the radial velocity method that this planet didn't complete the orbit during the continuous observations, the error range for orbital period is very large, at 4885 ± 1600 days or 13.37 ± 4.4 years. This puts it in the range of semimajor axes between 4.2 and 6.6 AU or between 630 and 990 Gm. So this planet will need couple more years of observations to better constrain the period and semimajor axis.