Scholz's Star ( WISE designation WISE 0720−0846 or fully WISE J072003.20−084651.2) is a dim binary stellar system 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 ...

in the

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 ...

Monoceros Monoceros ( Greek: , "unicorn") is a faint constellation on the celestial equator. Its definition is attributed to the 17th-century cartographer Petrus Plancius. It is bordered by Orion to the west, Gemini to the north, Canis Major to the s ...

near the

galactic plane The galactic plane is the plane (geometry), 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 ''galac ...

. It was discovered in 2013 by astronomer Ralf-Dieter Scholz. In 2015, Eric Mamajek and collaborators reported that the system passed through the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

Oort cloud The Oort cloud (pronounced or ), sometimes called the Öpik–Oort cloud, is scientific theory, theorized to be a cloud of billions of Volatile (astrogeology), icy planetesimals surrounding the Sun at distances ranging from 2,000 to 200,000 A ...

roughly 70,000 years ago in a stellar encounter, and dubbed it ''Scholz's Star''.

Characteristics

The primary is a

red dwarf A red dwarf is the smallest kind of star on the main sequence. Red dwarfs are by far the most common type of fusing star in the Milky Way, at least in the neighborhood of the Sun. However, due to their low luminosity, individual red dwarfs are ...

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 M and

Jupiter mass The Jupiter mass, also called Jovian mass, is the unit of mass equal to the total mass of the planet Jupiter. This value may refer to the mass of the planet alone, or the mass of the entire Jovian system to include the moons of Jupiter. Jupiter ...

es. The secondary is probably a T5 brown dwarf with Jupiter masses. The system has 0.15

solar mass 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, galaxie ...

es. The pair orbit at a distance of about with a period of roughly 4 years. The system has an

apparent magnitude Apparent magnitude () is a measure of the Irradiance, 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 (astronomy), ...

of 18.3, and is estimated to be between 3 and 10 billion years old. With a parallax of 166

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), ...

(0.166 arcseconds), about 80 star systems are known to be closer to the Sun. It is a late discovery, as far as nearby stars go, because of its dim magnitude and that past efforts concentrated on high-proper-motion objects.

Solar System flyby

Estimates indicate that the WISE 0720−0846 system passed about from the Sun about 70,000 years ago. Ninety-eight percent of mathematical simulations of the star system's trajectory indicated that it passed through the Solar System's

, or within of the Sun. Comets perturbed from the Oort cloud would require roughly two million years to get to the inner Solar System. Consisting of the smaller and dimmer red and a brown dwarf star even at closest approach the system would have only had an apparent magnitude of about 11.4, too dim for the unaided eye, but with instruments would have been best viewed from high latitudes in the northern hemisphere. However 70,000 years ago humans were still Stone Age Middle Paleolithic hunter-gathers. In 2018, research was published indicating that disturbance of the Oort cloud will have a greater effect than initial research had indicated. In a recent estimate, WISE J0720−0846AB passed within 68.7 ± 2.0 kAU of the Sun 80.5 ± 0.7 kyr ago. A later recalculation of the impact parameters using updated Solar System data showed that the perihelion distance during the encounter had a median value of 0.330 pc with a 90% probability of having come within 0.317–0.345 pc of the Sun; the associated time of perihelion passage was determined to be between 78.6–81.1 kyr ago with 90% confidence, with a most likely value of 79.9 kyr. A star is expected to pass through the Oort cloud every 100,000 years or so. An approach as close or closer than 52,000 AU is expected to occur about every 9 million years. In about 1.4 million years,

Gliese 710 Gliese 710, or HIP 89825, is an orange star in the constellation Serpens Cauda. It is projected to pass near the Sun in about 1.29 million years at a predicted minimum distance of 0.051 parsecs— (about 1.6 trillion km)—about 1/25th o ...

will come to a perihelion of between 8,800 and 13,700 AU.

Naming

The star was first discovered to be a nearby one by astronomer Ralf-Dieter Scholz, announced on

arXiv arXiv (pronounced as "archive"—the X represents the Chi (letter), Greek letter chi ⟨χ⟩) is an open-access repository of electronic preprints and postprints (known as e-prints) approved for posting after moderation, but not Scholarly pee ...

in November 2013. Given the importance of the system having passed so close to the Solar System in prehistorical times, Eric Mamajek and collaborators dubbed the system Scholz's star in their paper discussing the star's velocity and past trajectory.

References

{{DEFAULTSORT:Scholz's Star 201311?? Binary stars Brown dwarfs M-type main-sequence stars T-type brown dwarfs Monoceros Stars with proper names WISE objects J07200325-0846499 Oort cloud

Characteristics

Solar System flyby

Naming

See also

References