15 Sagittae
Encyclopedia
15 Sagittae is a 6th magnitude
star
in the constellation
Sagitta
. In 2002, a brown dwarf
, 15 Sge b, was discovered around 15 Sge.
, 15 Sge B is the first brown dwarf candidate orbiting a sun-like star detected directly.
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...
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....
Sagitta
Sagitta
Sagitta is a constellation. Its name is Latin for "arrow", and it should not be confused with the larger constellation Sagittarius, the archer. Although ancient, it is insignificant, for it has no star brighter than the 4th magnitude and is the third smallest of all constellations...
. In 2002, 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...
, 15 Sge b, was discovered around 15 Sge.
15 Sagittae B
15 Sagittae B is a probably a substellar L dwarf of spectral class L6±1.5 orbiting primary 15 Sagittae A. Imaged by the KeckKeck telescopes
The W. M. Keck Observatory is a two-telescope astronomical observatory at an elevation of near the summit of Mauna Kea in Hawai'i. The primary mirrors of each of the two telescopes are in diameter, making them the second largest optical telescopes in the world, slightly behind the Gran Telescopio...
, 15 Sge B is the first brown dwarf candidate orbiting a sun-like star detected directly.