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 center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
in the
constellation Monoceros
Monoceros (Greek: Μονόκερως, "unicorn") is a faint constellation on the celestial equator. Its definition is attributed to the 17th-century Dutch cartographer Petrus Plancius. It is bordered by Orion to the west, Gemini to the north, ...
near 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 ...
.
It was discovered in 2013 by astronomer Ralf-Dieter Scholz. In 2015, Eric Mamajek and collaborators reported the system passed through the
Solar System
The Solar System Capitalization 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 "Solar ...
's
Oort cloud
The Oort cloud (), sometimes called the Öpik–Oort cloud, first described in 1950 by the Dutch astronomer Jan Oort, is a theoretical concept of a cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from ...
roughly 70,000 years ago,
and dubbed it ''Scholz's Star''.
Characteristics
The primary is a
red dwarf with a
stellar classification of M and
Jupiter mass
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 is by ...
es.
The secondary is probably a
T5 brown dwarf with Jupiter masses.
The system has 0.15
solar masses.
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 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 ...
of 18.3,
and is estimated to be between 3 and 10 billion years old.
With a parallax of 166
mas (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 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
Oort cloud
The Oort cloud (), sometimes called the Öpik–Oort cloud, first described in 1950 by the Dutch astronomer Jan Oort, is a theoretical concept of a cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from ...
, or within of the Sun.
Comets
perturbed from the Oort cloud would require roughly two million years to get to the inner Solar System.
At closest approach the system would have had an apparent magnitude of about 11.4, and would have been best viewed from high latitudes in the northern hemisphere.
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 2018, a research was published indicating that disturbance of the Oort cloud will have a greater effect than initial research had indicated.
[Dvorsky, George (2018-03-21). ]
A Visiting Star Jostled Our Solar System 70,000 Years Ago
', Gizmodo, 21 March 2018.
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.
As a side note, 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 1.60 trillion km) – about 1/25 ...
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 "archive"—the X represents the 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 peer review. It consists of ...
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.
See also
*
List of nearest stars and brown dwarfs#Distant future and past encounters
*
HIP 85605
*
Stars named after people
Over the past few centuries, a small number of stars have been named after individual people. It is common in astronomy for objects to be given names, in accordance with accepted astronomical naming conventions. Most stars have not been given prope ...
References
{{DEFAULTSORT:Scholz's Star
201311??
Binary stars
Brown dwarfs
M-type main-sequence stars
T-type stars
Monoceros (constellation)
Stars with proper names
WISE objects
J07200325-0846499
Oort cloud