1SWASP J140747.93−394542.6 (also known as 1SWASP J140747, J1407 and Mamajek's Object) is a star similar to 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

Centaurus Centaurus is a bright constellation in the southern sky. One of the largest constellations, Centaurus was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. ...

at a distance of about 434 light-years from Earth. A relatively young star, its age is estimated to be 16 million years, and its mass is about 90% that of the Sun. The star 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 12.3 and requires a telescope to be seen. The star's name comes from the SuperWASP (

Wide Angle Search for Planets WASP or Wide Angle Search for Planets is an international consortium of several academic organisations performing an ultra-wide angle search for exoplanets using transit photometry. The array of robotic telescopes aims to survey the entire sky, ...

) program and the star's coordinates. The star is variable due to the planet orbiting around it and has been given the variable star designation V1400 Centauri. In 2007, J1407 was observed to be eclipsed and orbited by at least one major body, 1SWASP J1407b (J1407b), thought to be either a large

gas giant A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" ...

planet or 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 ...

, with an immense ring system. Subsequent observations have not successfully detected J1407b, suggesting that it is on a highly eccentric orbit around the star. By 2021, it was discovered the parent star is strongly variable, with a 5.4-year long magnetic activity cycle, and no evidence was detected of additional planets or a repeat of the deep eclipses attributed to a transiting ring system.

Suspected planetary system

The discovery of the J1407 system and its unusual

eclipses An eclipse is an astronomical event that occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three ce ...

were first reported by a team led by

University of Rochester The University of Rochester (U of R, UR, or U of Rochester) is a private university, private research university in Rochester, New York. The university grants Undergraduate education, undergraduate and graduate degrees, including Doctorate, do ...

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, moons, comets and galaxies – in either ...

Eric Mamajek in 2012. The existence and parameters of the ring system around the substellar companion J1407b were deduced from the observation of a very long and complex eclipse of the parent star lasting 56 days during April and May 2007. The low-mass companion J1407b has been referred to as a " Saturn on steroids" or " Super Saturn" due to its massive system of circumplanetary rings with a radius of approximately 90 million km (0.6 AU). The orbital period of J1407b is estimated to be around a decade (3.5 to 13.8 years), and its most probable mass is approximately 13 to 26

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...

masses, but with considerable uncertainty. The ringed body can be ruled out as being a star with mass of over 80

masses at greater than 99% confidence. The ring system has an estimated mass similar to that of the Earth. A major gap in the rings at about 61 million km (0.4 AU) from its centre is considered to be indirect evidence of the existence of an

exomoon An exomoon or extrasolar moon is a natural satellite that orbits an exoplanet or other non-stellar extrasolar body. Exomoons are difficult to detect and confirm using current techniques, and to date there have been no confirmed exomoon detecti ...

with mass up to 0.8 Earth masses. J1407b is the first exoplanet or

discovered with a

ring system A ring system is a disc or ring, orbiting an astronomical object, that is composed of solid material such as dust and moonlets, and is a common component of satellite systems around giant planets. A ring system around a planet is also known as ...

by the

transit method Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty o ...

. A sequence of occultations (eclipses) of the star occurred over a 56-day period in 2007. The pattern was consistent with that expected for the transit of a large array of multiple rings, indicating the substellar companion dubbed "J1407b". The J1407b ring system has an outer radius of approximately 90 million km (about 640 times the extent of Saturn's rings). Cleared gaps in the rings indicate satellites (" exomoons") have accreted from denser rings. The young age of the stellar system (about 16 million years) and the high mass of the ring system (roughly an Earth mass) are more consistent with it being an early (proto-)exomoon or moons, rather than a long-term stable ring system in an evolved planetary system (such as Saturn's rings). J1407b has not been observed since its transit in 2007, suggesting that it is on a highly eccentric orbit around the star. Such an orbit could disrupt the ring system of J1407b. Dynamical simulations run by astronomers Steven Rieder and Matthew Kenworthy indicate that in order for J1407b's ring system to be stable, the rings must orbit J1407b in a

retrograde motion Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is, the central object (right figure). It may also describe other motions such as precession ...

, opposite to the direction J1407b orbits its host star. This retrograde solution for the ring system of J1407b allows for longer ring lifetimes as well as further constraints to the age of the ring system. The rings may be replenished over timescales as a result of processes that produce additional debris around J1407b, such as the tidal disruption of

comets A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...

. From Earth's point of view, the ring system of J1407b would have an

angular diameter The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is ...

of about 3.7

milliarcsecond A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The n ...

s across. For comparison, if Saturn were as many light years away, its rings in full breadth would be 0.006 milliarcseconds across, and the diameter of

Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Sun. It is the largest ...

from earth varies between 60 and 110 milliarcseconds across.Pluto Fact Sheet
NASA No additional transits from Jupiter-sized or larger planets were discovered in a 19-year long observational series by 2021.

Notes

:1.J1407b ring system diameter = 0.0000190 ly; distance = ~439 ly. 0.0000190/439=0.000000043 of the sky; 0.00000104 degrees; 0.000062

arcminute A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The n ...

s; 0.00374 arcseconds; 3.74 milliarcseconds
Saturn's main ring system diameter ( D-F rings) = 0.0000000296 ly; distance = 439 ly. 0.0000000296/439=0.0000000000674 of the sky; 0.00000000162 degrees; 0.000000097 arcminutes; 0.00000583 arcseconds; 0.00583 milliarcseconds

References

External links

Extrasolar Planet Encyclopedia page on J1407b, (Accessed January 29, 2015)

Exoring model for J1407b
on ''

Vimeo Vimeo, Inc. () is an American video hosting, sharing, and services platform provider headquartered in New York City. Vimeo focuses on the delivery of high-definition video across a range of devices. Vimeo's business model is through software a ...

''.
'Saturn on Steroids': 1st Ringed Planet Beyond Solar System Possibly Found

{{DEFAULTSORT:1SWASP J140747.93-394542.6 Centaurus (constellation) Hypothetical planetary systems Planetary rings Exoplanets discovered in 2012 K-type subgiants Variable stars Centauri, V1400

Suspected planetary system

See also

Notes

References

External links