Gliese 752 is a binary star system in the Aquila

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 ...

. This system is relatively nearby, at a distance of . The Gliese 752 system consists of two M-type stars. The primary star is the

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

9 ''Gliese (GJ) 752 A''. The secondary star is the dim

17 ''Gliese (GJ) 752 B'', more commonly referred to as '' VB 10''. This stellar pair form a

binary star system A binary star or binary star system is a Star system, system of two stars that are gravity, 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 ...

separated by about 74 arc seconds (~434 AU). This system is also known for its high

proper motion Proper motion is the astrometric measure of changes in the apparent places of stars or other celestial objects as they move relative to the center of mass of the Solar System. It is measured relative to the distant stars or a stable referenc ...

of about 1 arc second a year. Component A has one known exoplanet. The name and number are from the '' Catalogue of Nearby Stars'', published by German astronomer

Wilhelm Gliese Wilhelm Gliese (, English ; 21 June 1915 – 12 June 1993) was a German astronomer who specialized in the study and cataloging of nearby stars. Life Gliese was born in Goldberg, now in Polish Silesia, the son of judge Wilhelm Gliese. He wo ...

in 1969.

Gliese 752 A characteristics

The primary star, also known as ''Wolf 1055'', is a type M2.5

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 about half the size and mass as 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 ...

and considerably cooler at . This star was first observed to be a high

star by the German astronomer

Max Wolf Maximilian Franz Joseph Cornelius Wolf (21 June 1863 – 3 October 1932) was a German astronomer and a pioneer in the field of astrophotography. He was the chairman of astronomy at the University of Heidelberg and director of the Heidelberg-K� ...

with his pioneering use of

astrophotography Astrophotography, also known as astronomical imaging, is the photography or imaging of astronomical objects, celestial events, or areas of the night sky. The first photograph of an astronomical object (the Moon) was taken in 1839, but it was no ...

. He added this star to his extensive catalog of such stars in 1919. It is a variable star with the

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...

catalog name ''V1428 Aquilae''. It is a '' BY Draconis'' type

subject to flare events.

Planetary system

In August 2018, a group of scientists using measurements taken from the CARMENES spectrograph, on the

Calar Alto Observatory The Calar Alto Observatory (Centro Astronómico Hispano en Andalucía or "Spanish Astronomical Centre in Andalusia") is an astronomical observatory located in Almería province in Spain on Calar Alto, a mountain in the Sierra de Los Filabre ...

located in Spain, announced they had detected a planet orbiting the larger of the stars, HD 180617 (Gliese 752 A). The measurements indicated the presence of a planet with a

minimum mass In astronomy, minimum mass is the lower-bound calculated mass of observed objects such as planets, stars, binary systems, nebulae, and black holes. Minimum mass is a widely cited statistic for extrasolar planets detected by the radial velocit ...

comparable to Neptune on an orbit partly located within the habitable zone.

Gliese 752 B characteristics

Gliese 752 was not known to be a binary star system until the discovery of a small dim secondary star by George Van Biesbroeck in 1944. This star is identified as '' VB 10'' in Van Biesbroeck's star catalog. This star is notable for its very low mass. At .08 solar masses, it is near the lower mass limit for a star. It is also quite small at 10% of the solar radius. A type M8V

, the star is known for its very low luminosity (one of the least luminous stars yet observed) with an absolute magnitude of nearly 19, due to its very cool surface temperature of only 2600K. It is a

with the

catalog name ''V1298 Aquilae''. This star is a '' UV Ceti'' type

also subject to flare events. It shares the large

, along with the tendency to

flare A flare, also sometimes called a fusée, fusee, or bengala, bengalo in several European countries, is a type of pyrotechnic that produces a bright light or intense heat without an explosion. Flares are used for distress signaling, illuminatio ...

, with the primary star. In 2009, the discovery of the

extrasolar planet An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first detect ...

, ''VB 10b'', was announced in orbit around this star. However a subsequent spectrographic survey failed to confirm the presence of any large planets in orbit around this star.

Magnetic field

In 1994, the

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

observed a

solar flare A solar flare is a relatively intense, localized emission of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and ot ...

on Gliese 752 B. This suggests that the star has a strong

magnetic field A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular ...

, which came as a surprise to astronomers. It had previously been assumed that low mass red dwarfs would have insignificant or nonexistent magnetic fields. These tiny dwarfs are supposed to lack the radiative zone just outside the star's core that creates the magnetic field-creating

dynamo "Dynamo Electric Machine" (end view, partly section, ) A dynamo is an electrical generator that creates direct current using a commutator. Dynamos employed electromagnets for self-starting by using residual magnetic field left in the iron cores ...

s in more massive stars like the

. Nevertheless, the detection of solar flares indicates that as yet unknown process allows low mass stars to produce sufficient magnetic fields to power such outbursts, even if solely by convection, without a radiative core.

References

{{DEFAULTSORT:Gliese 752 Aquila (constellation) 094761 M-type main-sequence stars Flare stars 180617 0752 Binary stars Planetary systems with one confirmed planet BD+04 4048 Aquilae, V1428/V1298 BY Draconis variables

1055 1055 (Roman numerals, MLV) was a common year starting on Sunday of the Julian calendar. Events By place Byzantine Empire * January 11 – Emperor Constantine IX Monomachos dies after a 12½-year reign at Constantinople. He is succee ...

Gliese 752 A characteristics

Planetary system

Gliese 752 B characteristics

Magnetic field

See also

References