HD 154857
Encyclopedia
|- bgcolor="#FFFAFA"
| Equatorial [ g
] || 54,7 m/s2
HD 154857 is a yellow main-sequence
star
approximately 224 light years away in the constellation
of Ara
.
has mass
>1.8 times that of Jupiter
. It orbits the star 20% further than Earth
-Sun
distance, taking 409 days with 47% eccentricity
. The unconfirmed planet HD 154857 c with unknown mass (probably around 18 Jupiter masses) takes at least 1900 days to orbit around the star with an orbital eccentricity exceeding 0.25.
| Equatorial [ g
G-force
The g-force associated with an object is its acceleration relative to free-fall. This acceleration experienced by an object is due to the vector sum of non-gravitational forces acting on an object free to move. The accelerations that are not produced by gravity are termed proper accelerations, and...
] || 54,7 m/s2
Metre per second squared
The metre per second squared is the unit of acceleration in the International System of Units . As a derived unit it is composed from the SI base units of length, the metre, and the standard unit of time, the second...
HD 154857 is a yellow main-sequence
Yellow dwarf
A G-type main-sequence star , often called a yellow dwarf, is a main-sequence star of spectral type G and luminosity class V. Such a star has about 0.8 to 1.2 solar masses and surface temperature of between 5,300 and 6,000 K., Tables VII, VIII...
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...
approximately 224 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....
of Ara
Ara (constellation)
Ara is a southern constellation situated between Scorpius and Triangulum Australe. Its name is Latin for "altar". Ara was one of the 48 Greek constellations described by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations defined by the International Astronomical...
.
Planetary system
There is one confirmed and one unconfirmed planet discovered in 2004 and 2007 respectively. The confirmed planet HD 154857 bHD 154857 b
HD 154857 b is an extrasolar planet approximately 224 light years away in the constellation of Ara. This is a gas giant mass that orbits the star in an eccentric orbit. This planet was detected by using Anglo-Australian Telescope UCLE spectrometer....
has mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
>1.8 times that of 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,...
. It orbits the star 20% further than Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
-Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
distance, taking 409 days with 47% 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...
. The unconfirmed planet HD 154857 c with unknown mass (probably around 18 Jupiter masses) takes at least 1900 days to orbit around the star with an orbital eccentricity exceeding 0.25.