1SWASP J140747.93-394542.6 b, also known as 1SWASP J1407b and J1407b, is an unconfirmed giant extrasolar planet orbiting the star V1400 Centauri. It is approximately 434 light years (or 133 parsecs) away from Earth in the constellation Centaurus.
Overview[]
Discovery[]
The discovery of the J1407 system and its bizarre eclipses were first discovered in 2012 by a team led by University of Rochester astronomer Eric Mamajek. The existence of a ring system around the planet were deduced from the observation of a very long and complex eclipse of the parent star, lasting 56 days between April and May 2007.
Characteristics[]
The planet has been described as a "Saturn on steroids", or a "Super Saturn", due to its massive circumplanetary ring system, which has a radius of approximately 90 million km (0.6 AU), or 640 times the extent of Saturn's rings. The orbital period of 1SWASP J140747.93-394542.6 b b is estimated to be somewhere between 3.5 to 13.8 years and it has a probable mass between 13 to 26 Jupiter masses, although the true mass is very uncertain. 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 is estimated to have a mass similar to that of Earth. An unexplained major gap in the rings at about 61 million km (0.4 AU) from its center could be indirect evidence of an exomoon with a mass of up to 0.8 Earth masses.
1SWASP J140747.93-394542.6 b b is the first exoplanet (or brown dwarf) discovered with a ring system using the transit method. A sequence of occultations (eclipses) of the star occurred over a 56-day period, in 2007.
Cleared gaps in the rings indicate that natural satellites ("exomoons") have accreted from denser ring. 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).
The planet has not been observed since its transit in 2007, suggesting it is in a highly eccentric orbit around the star. Such an eccentric orbit could disrupt the ring system of the planet. Dynamical simulations ran by astronomers Steven Rieder and Matthew Kenworthy indicate that in order for the planet's ring system to be stable, the rings must orbit it in a retrograde motion, opposite to the direction 1SWASP J140747.93-394542.6 b b orbits its star. This retrograde solution for the ring system of the planet 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 1SWASP J140747.93-394542.6 b b, such as the tidal disruption of comets.
From the Earth's point of view the ring system of 1SWASP J140747.93-394542.6 b b would have an angular diameter of about 3.7 milliarcseconds across. For comparison, if Saturn were as many light years away as 1SWASP J140747.93-394542.6 b b, its rings in full breadth would be about 0.006 milliarcseconds away.
Brown Dwarf Theory[]
One theory suggests that the planet can be a rogue sub-brown dwarf with a protoplanetary disk. One of the leading reasons for the theory is that it has only transited in 2007, though data of V1400 Centauri has been around since the 1850s.