Gliese 687, or GJ 687 ''(
Gliese–Jahreiß 687)'' is a
red dwarf
''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...
in the
constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The origins of the e ...
Draco
Draco is the Latin word for serpent or dragon.
Draco or Drako may also refer to:
People
* Draco (lawgiver) (from Greek: Δράκων; 7th century BC), the first lawgiver of ancient Athens, Greece, from whom the term ''draconian'' is derived
* D ...
. This is one of the
closest stars to the
Sun and lies at a distance of . Even though it is close by, it has an
apparent magnitude of about 9, so it can only be seen through a moderately sized
telescope. Gliese 687 has a high
proper motion
Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more dista ...
, advancing 1.304
arcsecond
A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The na ...
s per year across the sky. It has a net relative velocity of about 39 km/s.
It is known to have a Neptune-mass planet.
[ Old books and articles refer to it as Argelander Oeltzen 17415.]
Properties
Gliese 687 has about 40% of the Sun's mass 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.red dwarf
''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...
that emits X-rays.
Planetary system
In 2014, Gliese 687 was discovered to have a planet, Gliese 687 b, with a minimum mass of 18.394 Earth mass
An Earth mass (denoted as M_\mathrm or M_\oplus, where ⊕ is the standard astronomical symbol for Earth), is a unit of mass equal to the mass of the planet Earth. The current best estimate for the mass of Earth is , with a relative uncertainty ...
es (which makes it comparable to Neptune), an orbital period of 38.14 days, a low orbital eccentricity
In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values betwee ...
and inside the habitable zone.[
]
See also
* List of nearest stars and brown dwarfs
* List of exoplanets discovered in 2014
This is a List of exoplanets discovered in 2014.
For exoplanets detected only by radial velocity, the mass value is actually a lower limit. (See Minimum mass for more information)
Specific exoplanet lists
References
{{Exoplanet
2014
*
exop ...
- Gliese 687 b
* List of exoplanets discovered in 2020
This list of exoplanets discovered in 2020 is a list of confirmed exoplanets that were first observed in 2020.
For exoplanets detected only by radial velocity, the listed value for mass is a lower limit. See Minimum mass for more information.
...
- Gliese 687 c
References
Notes
External links
NEXXUS page
{{DEFAULTSORT:Gliese 687
Draco (constellation)
Local Bubble
M-type main-sequence stars
086162
0687
Planetary systems with two confirmed planets
BD+68 0946