V391 Pegasi b
Encyclopedia
V391 Pegasi b, also known as HS 2201+2610 b, is an extrasolar planet
orbiting the star V391 Pegasi
approximately 4570 light-year
s away in the constellation
of Pegasus
. The planet was discovered by means of variable star timing, which measured anomalies in variability of the star caused by a planet. It found to have mass
of 3.2 times Jupiter
, semi-major axis
of 1.7 AU
, and orbital period
of 1170 day
s. The planet was discovered in March 2007 and published in September 2007. Its survival indicates that planets at Earth-like distances can survive their star's red-giant phase, though this is a much larger planet than Earth (about the same size as Jupiter and Saturn).
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...
orbiting the star V391 Pegasi
V391 Pegasi
V391 Pegasi, also catalogued as HS 2201+2610, is a blue-white subdwarf star approximately 4,570 light-years away in the constellation of Pegasus. The star is clarified as an "extreme horizontal branch star." It is small with only half the mass and one-over-four-and-one-thirds the diameter of the...
approximately 4570 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s 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 Pegasus
Pegasus (constellation)
Pegasus is a constellation in the northern sky, named after the winged horse Pegasus in Greek mythology. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.-Stars:...
. The planet was discovered by means of variable star timing, which measured anomalies in variability of the star caused by a planet. It found to have 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:...
of 3.2 times 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,...
, semi-major axis
Semi-major axis
The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape...
of 1.7 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
, and orbital period
Orbital period
The orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of...
of 1170 day
Day
A day is a unit of time, commonly defined as an interval equal to 24 hours. It also can mean that portion of the full day during which a location is illuminated by the light of the sun...
s. The planet was discovered in March 2007 and published in September 2007. Its survival indicates that planets at Earth-like distances can survive their star's red-giant phase, though this is a much larger planet than Earth (about the same size as Jupiter and Saturn).