109 Piscium b
Encyclopedia
109 Piscium b is a long-period extrasolar planet discovered in orbit around 109 Piscium
. It is at least 6.38 times the mass of Jupiter
and is likely to be a gas giant
. As typical for long-period planets discovered around other stars, it has an orbital eccentricity
greater than that of Jupiter.
The discoverers estimate its effective temperature
as 264 K
from solar heating, but it could be at least 10-20 K warmer because of internal heat
ing.
Preliminary astrometric
measurements suggested that the orbital inclination is 170.3°, yielding an object mass of 38 times that of Jupiter, which would make it a brown dwarf
. However, subsequent analysis indicates that the precision of the measurements used to derive the astrometric orbit is insufficient to constrain the parameters, so the true inclination and mass remain unknown.
109 Piscium
109 Piscium is a yellow subgiant star located about 106 light years away in the constellation Pisces. It has a similar mass to our Sun, and has a higher abundance of iron.-Planetary system:In 1999 an extrasolar planet was detected around this star....
. It is at least 6.38 times the mass 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,...
and is likely to be a gas giant
Gas giant
A gas giant is a large planet that is not primarily composed of rock or other solid matter. There are four gas giants in the Solar System: Jupiter, Saturn, Uranus, and Neptune...
. As typical for long-period planets discovered around other stars, it has an orbital 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...
greater than that of Jupiter.
The discoverers estimate its effective temperature
Effective temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation...
as 264 K
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...
from solar heating, but it could be at least 10-20 K warmer because of internal heat
Internal heat
Internal heat is the heat source from the interior of celestial objects, such as planets, brown dwarfs, and stars, caused by gravity, nuclear fusion and decaying radioactive materials. The amount of internal heating depends on mass; the more massive the object, the more internal heat it has...
ing.
Preliminary astrometric
Astrometry
Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...
measurements suggested that the orbital inclination is 170.3°, yielding an object mass of 38 times that of Jupiter, which would make it a brown dwarf
Brown dwarf
Brown dwarfs are sub-stellar objects which are too low in mass to sustain hydrogen-1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no chemical differentiation by depth...
. However, subsequent analysis indicates that the precision of the measurements used to derive the astrometric orbit is insufficient to constrain the parameters, so the true inclination and mass remain unknown.