* Astronomy

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RE: 1SWASP J140747.93-394542.6

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Distant exoplanet hosts giant ring system

Astronomers say they have discovered a planet with a gigantic ring system that is 200 times larger than that around Saturn.
It is the first such structure detected around a planet beyond our Solar System.
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Gigantic ring system around J1407b much larger, heavier than Saturn's

Astronomers at the Leiden Observatory, The Netherlands, and the University of Rochester, USA, have discovered that the ring system that they see eclipse the very young Sun-like star J1407 is of enormous proportions, much larger and heavier than the ring system of Saturn. The ring system - the first of its kind to be found outside our solar system - was discovered in 2012 by a team led by Rochester's Eric Mamajek.
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Eclipsing Ring System J1407

1SWASP J140747.93-394542.6 ("J1407") is a recently discovered young variable star that had an extraordinarily deep, long, and complex eclipse in early 2007. The eclipses took place over a ~52 day period, with the deepest portion being ~3.3 magnitudes fainter than the out-of-eclipse mean brightness (V ~ 12.3 mag).
In Mamajek et al. (2012), we propose that the eclipse sequence in 2007 appears to be due to the presence of a low-mass object (probably substellar object - likely a brown dwarf or giant planet) with a series of discrete rings orbiting it. If it is a giant planet, this may be the first instance of a "protoexosatellite disk" - i.e. a circumplanetary disk where moon formation is taking place (small bodies are likely present to dynamically sculpt the ring system). If it is a brown dwarf, then we are similarly seeing the dust signatures of the formation of a miniature planetary system. Either way, this is an interesting and, so far, unique system.
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Scientists Discover a Saturn-like Ring System Eclipsing a Sun-like Star

A team of astrophysicists from the University of Rochester and Europe has discovered a ring system in the constellation Centaurus that invites comparisons to Saturn.
The scientists, led by Assistant Professor of Physics and Astronomy Eric Mamajek of Rochester and the Cerro Tololo Inter-American Observatory, used data from the international SuperWASP (Wide Angle Search for Planets) and All Sky Automated Survey (ASAS) project to study the light curves of young Sun-like stars in the Scorpius-Centaurus association - the nearest region of recent massive star formation to the Sun.
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Scientists Discover a Saturn-Like Ring System Eclipsing a Sun-Like Star

New York-A team of astrophysicists from the University of Rochester and Europe has discovered a ring system in the constellation Centaurus that invites comparisons to Saturn.
The scientists, led by Assistant Professor of Physics and Astronomy Eric Mamajek of Rochester and the Cerro Tololo Inter-American Observatory, used data from the international SuperWASP (Wide Angle Search for Planets) and All Sky Automated Survey (ASAS) project to study the light curves of young Sun-like stars in the Scorpius-Centaurus association - the nearest region of recent massive star formation to the Sun.
If a spherical object merely passed in front of the star, the intensity of the light would gradually dim and reach a low point before gradually increasing. That was not the case with the star identified as 1SWASP J140747.93-394542.6. The Rochester team discovered a long, deep, and complex eclipse event with significant on-and-off dimming. At the deepest parts of the eclipse, at least 95% of the light from the star was being blocked by dust.
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Title: Planetary Construction Zones in Occultation: Eclipses by Circumsecondary and Circumplanetary Disks and a Candidate Eclipse of a Pre-Main Sequence Star in Sco-Cen
Authors: Eric E. Mamajek, Alice C. Quillen, Mark Pecaut, Fred Moolekamp, Erin L. Scott, Matthew Kenworthy, Andrew Collier Cameron, Neil Parley

The large relative sizes of circumstellar and circumplanetary disks imply that they might be seen in eclipse in stellar light curves. We present photometric and spectroscopic data for a pre-main sequence K5 star (1SWASP J140747.93-394542.6 = ASAS J140748-3945.7), a newly discovered ~0.9 Msun member of the ~16 Myr-old Upper Centaurus-Lupus subgroup of Sco-Cen at a distance of 128±13 pc. This star exhibited a remarkably long, deep, and complex eclipse event centred on 29 April 2007 (as discovered in SuperWASP photometry, and with portions of the dimming confirmed by ASAS data). At least 5 multi-day dimming events of >0.5 mag are identified, with a >3.3 mag deep eclipse bracketed by two pairs of ~1 mag eclipses symmetrically occurring ±12 days and ±26 days before and after. Hence, significant dimming of the star was taking place on and off over at least a ~54 day period in 2007, and a strong >1 mag dimming event occurring over a ~12 day span. We place a firm lower limit on the period of 850 days (i.e. the orbital radius of the eclipser must be >1.7 AU and orbital velocity must be <22 km/s). The shape of the light curve is similar to the lop-sided eclipses of the Be star EE Cep, and we suspect that this new star is being eclipsed by a low-mass object with an orbiting disk with significant substructure (thin dust debris belts or "rings"). In the new era of time-domain astronomy opened by surveys like SuperWASP, ASAS, etc., and soon to be revolutionised by LSST, it is likely that eclipses by circumplanetary and circumsecondary disks will provide us fine-scale (~AU to Rstar scales) observational constraints on the physical and chemical conditions of the dust and gas which spawn satellite systems around gas giant planets and planetary systems around stars.