star system
A star system or stellar system is a small number of stars that orbit each other, bound by gravity, gravitational attraction. It may sometimes be used to refer to a single star. A large group of stars bound by gravitation is generally calle ...
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 first constellati ...
of
Orion
Orion may refer to:
Common meanings
* Orion (constellation), named after the mythical hunter
* Orion (mythology), a hunter in Greek mythology
Arts and media
Fictional entities Characters and species
* Orion (character), a DC Comics c ...
. It has the
Bayer designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...
A Orionis, while ''32 Orionis'' is the
Flamsteed designation
A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the 88 modern constellations, modern constellations visible from southern England. They are named after John Flamsteed, au ...
. This system is visible to the naked eye as a faint point of light with a combined
apparent visual magnitude
Apparent magnitude () is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...
of 4.20. It is located approximately 303
light-year
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...
s away from the
Sun
The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...
based on
parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...
, and is drifting further away with a
radial velocity
The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ...
of +18.6 km/s.
The system is a member of the eponymous 32 Orionis group, a young, nearby
association
Association may refer to:
*Club (organization), an association of two or more people united by a common interest or goal
*Trade association, an organization founded and funded by businesses that operate in a specific industry
*Voluntary associatio ...
of 46 co-moving stars first discovered in 2007. Research in 2015 suggested that
Bellatrix
Bellatrix is the third-brightest star and a candidate binary star in the constellation of Orion, positioned 5° west of the red supergiant Betelgeuse (Alpha Orionis). It has the Bayer designation γ Orionis, which is Latinized to Gamma ...
is a probable member of the group due to its distance and position in the sky and suggested it be called the Bellatrix Cluster, although further research in 2017 called Bellatrix's membership into question due to its proper motion deviating significantly from the group.
The primary component of this system is a
B-type main-sequence star
A B-type main-sequence star (B V) is a main-sequence (hydrogen-burning) star of spectral type B and luminosity class V. These stars have from 2 to 16 times the mass of the Sun and surface temperatures between 10,000 and 30,000 K. B-type stars ...
with a
stellar classification
In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction gratin ...
of B5V and a magnitude around 4.43. This is actually a
spectroscopic binary
A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved as separate stars us ...
with an
orbital period
The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...
of 3.964 days and
eccentricity
Eccentricity or eccentric may refer to:
* Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal"
Mathematics, science and technology Mathematics
* Off-Centre (geometry), center, in geometry
* Eccentricity (g ...
of 0.38. The unseen companion has an estimated mass of 0.6 times that of the Sun. Component B, at an
angular separation
Angular distance or angular separation is the measure of the angle between the orientation of two straight lines, rays, or vectors in three-dimensional space, or the central angle subtended by the radii through two points on a sphere. When t ...
of from the primary, is a class B7V star with a magnitude of 5.8, orbiting with the primary at a period of 614 years and eccentricity 0.22.
1839
Events
January–March
* January 2 – The first photograph of the Moon is taken, by French photographer Louis Daguerre.
* January 6 – Night of the Big Wind: Ireland is struck by the most damaging cyclone in 300 years.
* January 9 – ...