1SWASP J140747.93−394542.6 is a star similar to the Sun in the constellation Centaurus 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 of 12.3 and requires a telescope to be seen. The star's name comes from the SuperWASP program and the star's coordinates. The star is variable due to the planet orbiting around it and has been given the variable star designationV1400 Centauri. In 2007, J1407 was observed to be eclipsed and orbited by at least one major body, 1SWASP J1407b, thought to be either a large gas giant planet or a brown dwarf with an immense ring system. Subsequent observations have not successfully detected J1407b, suggesting that it is on a highly eccentric orbit around the star.
1SWASP J140747.93−394542.6 b
The discovery of the J1407 system and its unusual eclipses were first reported by a team led by University of RochesterastronomerEric 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. The orbital period of J1407b is estimated to be around a decade, and its most probable mass is approximately 13 to 26 Jupiter masses, but with considerable uncertainty. The ringed body can be ruled out as being a star with mass of over 80 Jupiter 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 from its centre is considered to be indirect evidence of the existence of an exomoon with mass up to 0.8 Earth masses. J1407b is the first exoplanet or brown dwarf discovered with a ring system by the transit method. A sequence of occultations 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. Cleared gaps in the rings indicate satellites have formed accreted from denser rings. The young age of the stellar system and the high mass of the ring system are more consistent with it being an early exomoon or moons, rather than a long-term stable ring system in an evolved planetary system. J1407b has not been observed since its transit in 2007, suggesting that it is on a highly eccentric orbit around the star. Such a highly eccentric orbit around the star could disrupt the ring system of J1407b. Dynamical simulations ran 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, 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. From Earth's point of view, the ring system of J1407b would have an angular diameter of about 3.7 milliarcseconds across. For comparison, if Saturn were as many light years away, its rings in full breadth would be 0.006 milliarcseconds across.
