binary star
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 ...
system in the
zodiac
The zodiac is a belt-shaped region of the sky that extends approximately 8° north and south celestial latitude of the ecliptic – the apparent path of the Sun across the celestial sphere over the course of the year. Within this zodiac ...
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
Sagittarius
Sagittarius ( ) may refer to:
*Sagittarius (constellation)
*Sagittarius (astrology), a sign of the Zodiac
* Sagittarius of Gap, a 6th century bishop
*Sagittarius A*, the supermassive black hole at the center of the Milky Way galaxy
Ships
*'' S ...
. The pair have 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 +5.03, which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 12.95
mas
Mas, Más or MAS may refer to:
Film and TV
* Más y Menos, fictional superhero characters, from the Teen Titans animated television series
* "Más" (''Breaking Bad''), a season three episode of ''Breaking Bad''
Music Albums
* ''Más'' (album), ...
as seen from Earth, it is located around 252
light year
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...
s 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 ...
. It is advancing through space in the general direction of the Earth 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 −43.4 km/s.
This is a visual binary 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 5.72 years, an
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 0.710, and an angular
semimajor axis
In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the long ...
of 69 mas. The primary, component A, is an
A-type star A type or type A may refer to: Science
* A-type asteroid, a type of relatively uncommon inner-belt asteroids
* A type blood, a type in the ABO blood group system
* A-type inclusion, a type of cell inclusion
* A-type potassium channel, a type of ...
showing a mixed
spectrum
A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...
that matches 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 A3/5 IV/V.
Helmut Abt
Helmut Arthur Abt (26 May 1925 – 22 November 2024) was a German-born American astrophysicist, having worked at the National Optical Astronomy Observatory and an Elected Fellow of the American Association for the Advancement of Science. He wa ...
classified it as an
Am star
An Am star or metallic-line star is a type of chemically peculiar star of spectral type A whose spectrum has strong and often variable absorption lines of metals such as zinc
Zinc is a chemical element; it has symbol Zn and atomic number 30. ...
with a spectral type of kA5hF0VmF0. This notation indicates it has the
calcium K-line
The Fraunhofer lines are a set of spectral absorption lines. They are dark absorption lines, seen in the optical spectrum of the Sun, and are formed when atoms in the solar atmosphere absorb light being emitted by the solar photosphere. The line ...
s of an A5 star, and the
hydrogen
Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...
and metal lines of an F0 star. It is around 393 million years old and is spinning with a
projected rotational velocity
Stellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface.
The rotation of a star produces an equatorial bu ...
of 54 km/s. The star has an estimated 1.6 times the
mass of the Sun
The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies a ...
and is radiating 42.9 times the
Sun's luminosity
The solar luminosity () is a unit of radiant flux ( power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun.
One nominal s ...
from its
photosphere
The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will esc ...
at an
effective temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...