binary star
A binary star 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 using a telescope as separate stars, in wh ...
in the southern
circumpolar constellation
A circumpolar star is a star that, as viewed from a given latitude on Earth, never sets below the horizon due to its apparent proximity to one of the celestial poles. Circumpolar stars are therefore visible from said location toward the nearest po ...
of
Musca
Musca () is a small constellation in the deep southern sky. It was one of 12 constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman, and it first appeared on a celestial globe in dia ...
. With a combined
apparent visual magnitude
Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...
of 3.07, it is the second brightest star (or star system) in the constellation. Judging by the
parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...
results, it is located at a distance of roughly from the
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
.
This is a
binary star system
A binary star 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 using a telescope as separate stars, in wh ...
with a
period
Period may refer to:
Common uses
* Era, a length or span of time
* Full stop (or period), a punctuation mark
Arts, entertainment, and media
* Period (music), a concept in musical composition
* Periodic sentence (or rhetorical period), a concept ...
of about 194 years at an
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 ...
of 0.6. As of 2007, the two stars had an
angular separation
Angular distance \theta (also known as angular separation, apparent distance, or apparent separation) is the angle between the two sightlines, or between two point objects as viewed from an observer.
Angular distance appears in mathematics (in pa ...
of 1.206
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 at a
position angle
In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the north celestial pole (NCP), turning positive into the d ...
of 35°. The components are
main sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...
stars of similar size and appearance. The primary component, β Muscae A, has an apparent magnitude of 3.51, 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 grati ...
of B2 V, and about 7.35 times the
Sun's mass
The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass of ...
. The secondary component, β Muscae B, has an apparent magnitude of 4.01, a stellar classification of B3 V, and is about 6.40 times the mass of the Sun.
This is a confirmed member of the
Scorpius–Centaurus association
The Scorpius–Centaurus association (sometimes called Sco–Cen or Sco OB2) is the nearest OB association to the Sun. This stellar association is composed of three subgroups (Upper Scorpius, Upper Centaurus–Lupus, and Lower Centaurus–Crux) ...
, which is a group of stars with similar ages, locations, and trajectories through space, implying that they formed together in the same
molecular cloud
A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit absorption nebulae, the formation of molecules (most commonly molecular hydrogen ...
. Beta Muscae is considered a
runaway star
In astronomy, stellar kinematics is the Observational astronomy, observational study or measurement of the kinematics or motions of stars through space.
Stellar kinematics encompasses the measurement of stellar Velocity, velocities in the Milky W ...
system as it has a high
peculiar velocity
Peculiar motion or peculiar velocity refers to the velocity of an object relative to a ''rest frame'' — usually a frame in which the average velocity of some objects is zero.
Galactic astronomy
In galactic astronomy, peculiar motion refers to ...
of relative to the normal galactic rotation. Runaway stars can be produced through several means, such as through an encounter with another binary star system. Binary systems form a relatively small fraction of the total population of runaway stars.