Nu Ophiuchi (ν Oph, ν Ophiuchi) is a star in the

equatorial Equatorial may refer to something related to: *Earth's equator **the tropics, the Earth's equatorial region **tropical climate *the Celestial equator ** equatorial orbit **equatorial coordinate system ** equatorial mount, of telescopes * equatorial ...

constellation of

Ophiuchus Ophiuchus () is a large constellation straddling the celestial equator. Its name comes from the Ancient Greek (), meaning "serpent-bearer", and it is commonly represented as a man grasping a snake. The serpent is represented by the constella ...

. The

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 ...

is +3.3, making it one of the brighter members of this constellation. Based upon parallax measurements made during the Hipparcos mission, this star is located about from

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 ...

Properties

Nu Ophiuchi has about three times the mass of the Sun and is roughly 330 million years old. The

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors ...

of the star matches a stellar classification of K0 IIIa, indicating it is a

giant star A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Press ...

that has exhausted the supply of hydrogen at its core and

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

away from the main sequence of stars. Unusually, it displays an anomalously low abundance of

cyanogen Cyanogen is the chemical compound with the formula ( C N)2. It is a colorless and highly toxic gas with a pungent odor. The molecule is a pseudohalogen. Cyanogen molecules consist of two CN groups – analogous to diatomic halogen molecu ...

for a star of its type. The star's outer envelope has expanded to around 14 times the Sun's radius and now radiates with a luminosity 123 times that of the Sun. This energy is emitted from its outer envelope at an effective temperature of 4,928 K, giving it the cool, orange hue of a

K-type star In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

Companions

This is not a binary star system in the sense of having a gravitationally-bound stellar companion. However, in November 2003, a

brown dwarf Brown dwarfs (also called failed stars) are substellar objects that are not massive enough to sustain nuclear fusion of ordinary hydrogen ( 1H) into helium in their cores, unlike a main-sequence star. Instead, they have a mass between the most ...

companion Nu Ophiuchi b was discovered. This sub-stellar companion has at least 21.9 times the mass of Jupiter and takes 536 days (1.47 years) to complete an

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...

. A second brown dwarf companion was discovered in 2010, orbiting further from the star with a period of 3,169 days (8.68 years). These have been confirmed in 2012. Two brown dwarfs are locked in 1:6

orbital resonance In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly, this relationsh ...

. This star is following an orbit through the galaxy that carries the star between from the

Galactic Center The Galactic Center or Galactic Centre is the rotational center, the barycenter, of the Milky Way galaxy. Its central massive object is a supermassive black hole of about 4 million solar masses, which is called Sagittarius A*, a compact ra ...

. As a probable member of the Milky Way's thin disk population, it has a low

orbital inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth ...

that carries it no more than about above the

galactic plane The galactic plane is the plane on which the majority of a disk-shaped galaxy's mass lies. The directions perpendicular to the galactic plane point to the galactic poles. In actual usage, the terms ''galactic plane'' and ''galactic poles'' usual ...

Naming

This star is sometimes called by the name Sinistra, meaning ''left side'' in

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

, although authors like

Jim Kaler James Bailey "Jim" Kaler (December 29, 1938 — November 26, 2022) was an American astronomer and science writer. After elementary and high-school education in Albany, New York, Kaler earned his A.B. at the University of Michigan in 1960. He atte ...

recommend not using this name, and instead stick to the Bayer designation only (Nu Ophiuchi). In China, the star is part of (), meaning '' Left Wall of Heavenly Market Enclosure.'' The stars in this group include ν Ophiuchi,

δ Herculis Delta Herculis (δ Herculis, abbreviated Delta Her, δ Her) is a multiple star system in the constellation of Hercules. Its light produces to us apparent magnitude 3.12, as such the third-brightest star in the large, fairly dim constell ...

λ Herculis Lambda Herculis (λ Herculis. abbreviated Lambda Her, λ Her), formally named Maasym , is a star in the constellation of Hercules. From parallax measurements taken during the Gaia mission, it is approximately 393 light-years from the S ...

μ Herculis Mu Herculis (μ Herculis) is a nearby quadruple star system about 27.1 light years from Earth in the constellation Hercules. Its main star, Mu Herculis A is fairly similar to the Sun although more highly evolved with a ste ...

, ο Herculis,

112 Herculis 112 Herculis is a binary star system in the northern constellation of Hercules. It is dimly visible to the naked eye with a combined apparent visual magnitude of 5.43. The secondary component is about two magnitudes fainter than the pr ...

ζ Aquilae Zeta Aquilae, or ζ Aquilae, is a binary star system in the equatorial constellation of Aquila. It is readily visible with the naked eye, being of the third magnitude. Based on parallax measurements obtained during the Hipparcos miss ...

, θ¹ Serpentis, η Serpentis, ξ Serpentis and

η Ophiuchi Eta Ophiuchi (η Ophiuchi, abbreviated Eta Oph, η Oph) is a binary star in the constellation of Ophiuchus. Based on parallax measurements taken during the Hipparcos mission, it is approximately 88 light-years from the Sun. Eta Op ...

. Consequently, ν Ophiuchi itself is known as (, en, the Ninth Star of Left Wall of Heavenly Market Enclosure), and together with ζ Capricorni represents the state

Yan Yan may refer to: Chinese states * Yan (state) (11th century – 222 BC), a major state in northern China during the Zhou dynasty * Yan (Han dynasty kingdom), first appearing in 206 BC * Yan (Three Kingdoms kingdom), officially claimed indepe ...

(燕) in the '' Twelve States'' constellation.

References

{{DEFAULTSORT:Nu Ophiuchi Ophiuchi, Nu Ophiuchus (constellation) K-type giants Brown dwarfs Planetary systems with two confirmed planets Ophiuchi, 64 088048 6698 163917 Durchmusterung objects J17590160-0946249

Properties

Companions

Naming

See also

References