Gl 687
Encyclopedia
Gliese 687, or GJ 687 (Gliese-Jahreiss
687) is a red dwarf
star
in the constellation
Draco
. This is one of the closest stars to the Sun
and lies at an approximate distance of less than 15 light years. Even though it is close by, it has a magnitude
of about 9 so it can only be seen through a moderate sized telescope
. The star has a high proper motion
across the sky, advancing 1.304 arc seconds per year. It has a net relative velocity of about 39 km/s.
and nearly 50% of the Sun's radius. Compared to the Sun, it has a slightly higher proportion of elements with higher atomic numbers than helium
. This star displays no excess of infrared
radiation that would indicate orbiting dust. Thus far no companion has been discovered orbiting this star.
Gliese Catalogue of Nearby Stars
The Gliese Catalogue of Nearby Stars is a frequently referenced, modern star catalogue of stars located within 25 parsecs of the Earth.-First edition and supplements:...
687) is a red dwarf
Red dwarf
According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool star, of the main sequence, either late K or M spectral type....
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...
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....
Draco
Draco (constellation)
Draco is a constellation in the far northern sky. Its name is Latin for dragon. Draco is circumpolar for many observers in the northern hemisphere...
. This is one of the closest stars to the 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...
and lies at an approximate distance of less than 15 light years. Even though it is close by, it has a magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
of about 9 so it can only be seen through a moderate sized telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
. The star has a high proper motion
Proper motion
The proper motion of a star is its angular change in position over time as seen from the center of mass of the solar system. It is measured in seconds of arc per year, arcsec/yr, where 3600 arcseconds equal one degree. This contrasts with radial velocity, which is the time rate of change in...
across the sky, advancing 1.304 arc seconds per year. It has a net relative velocity of about 39 km/s.
Properties
GJ 687 has about 40% of the Sun's massSolar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
and nearly 50% of the Sun's radius. Compared to the Sun, it has a slightly higher proportion of elements with higher atomic numbers than helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
. This star displays no excess of infrared
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
radiation that would indicate orbiting dust. Thus far no companion has been discovered orbiting this star.