The light curve of 1SWASP J140747.93-394542.6, a $sim$16 Myr old star in the Sco-Cen OB association, underwent a complex series of deep eclipses that lasted 56 days, centered on April 2007. This light curve is interpreted as the transit of a giant ri
ng system that is filling up a fraction of the Hill sphere of an unseen secondary companion, J1407b. We fit the light curve with a model of an azimuthally symmetric ring system, including spatial scales down to the temporal limit set by the stars diameter and relative velocity. The best ring model has 37 rings and extends out to a radius of 0.6 AU (90 million km), and the rings have an estimated total mass on the order of $100 M_{Moon}$. The ring system has one clearly defined gap at 0.4 AU (61 million km), which we hypothesize is being cleared out by a $< 0.8 M_{oplus}$ exosatellite orbiting around J1407b. This eclipse and model implies that we are seeing a circumplanetary disk undergoing a dynamic transition to an exosatellite-sculpted ring structure and is one of the first seen outside our Solar system.
The young (~16 Myr) pre-main-sequence star in Sco-Cen 1SWASP J140747.93-394542.6, hereafter referred to as J1407, underwent a deep eclipse in 2007 April, bracketed by several shallower eclipses in the surrounding 54 d. This has been interpreted as th
e first detection of an eclipsing ring system circling a substellar object (dubbed J1407b). We report on a search for this companion with Sparse Aperture Mask imaging and direct imaging with both the UT4 VLT and Keck telescopes. Radial velocity measurements of J1407 provide additional constraints on J1407b and on short period companions to the central star. Follow-up photometric monitoring using the PROMPT-4 and ROAD observatories during 2012-2014 has not yielded any additional eclipses. Large regions of mass-period space are ruled out for the companion. For circular orbits the companion period is constrained to the range 3.5-13.8 yr (a ~ 2.2-5.6 au), and masses greater than 80 M_Jup are ruled out at 3 sigma significance over these periods. The complex ring system appears to occupy more than 0.15 of its Hill radius, much larger than its Roche radius and suggesting a ring structure in transition. Further, we demonstrate that the radial velocity of J1407 is consistent with membership in the Upper Cen-Lup subgroup of the Sco-Cen association, and constraints on the rotation period and projected rotational velocity of J1407 are consistent with a stellar inclination of 68+-10 degrees.
We report on a search for low mass companions within 10 AU of the star Fomalhaut, using narrow band observations at 4.05 microns obtained with the Apodizing Phase Plate (APP) coronagraph on the VLT/NaCo. Our observations place a model dependent upper
mass limit of 12-20 Jupiter masses from 4 to 10 AU, covering the semi-major axis search space between interferometric imaging measurements and other direct imaging non-detections. These observations rule out models where the large semi-major axis for the putative candidate companion Fomalhaut b is explained by dynamical scattering from a more massive companion in the inner stellar system, where such giant planets are thought to form.
Gliese 569B is a multiple brown dwarf system whose exact nature has been the subject of several investigations over the past few years. Interpretation has partially relied on infra-red photometry and spectroscopy of the resolved components of the sys
tem. We present seeing limited Ks photometry over four nights, searching for variability in this young low mass substellar system. Our photometry is consistent with other reported photometry, and we report the tentative detection of several periodic signals consistent with rotational modulation due to spots on their surfaces. The five significant periods range from 2.90 hours to 12.8 hours with peak to peak variabilities from 28 mmag to 62 mmag in the Ks band. If both components are rotating with the shortest periods, then their rotation axes are not parallel with each other, and the rotation axis of the Bb component is not perpendicular to the Ba-Bb orbital plane. If Bb has one of the longer rotational periods, then the Bb rotation axis is consistent with being parallel to the orbital axis of the Ba-Bb system.
