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We present photometric observations and numerical simulations of 2016 SD$_{106}$, a low inclination ($i=4.8^{\circ}$) extreme trans-Neptunian Object with a large semi-major axis ($a=350$ au) and perihelion ($q= 42.6$ au). This object possesses a peculiar neutral color of $g-r = 0.45\pm0.05$ and $g-i=0.72\pm0.06$, in comparison with other distant trans-Neptunian objects, all of which have moderate-red to ultra-red colors. A numerical integration based on orbital fitting on astrometric data covering eight years of arc confirms that 2016 SD$_{106}$ is a metastable object without significant scattering evolution. Each of the clones survived at the end of the 1 Gyr simulation. However, very few neutral objects with inclinations $<5^{\circ}$ have been found in the outer solar system, even in the main Kuiper belt. Furthermore, most mechanisms which lift perihelion distances are expected to produce a very low number of extreme objects with inclinations $<5^{\circ}$. We thus explored the possibility that a hypothetical distant planet could increase the production of such objects. Our simulations show that no 2016 SD$_{106}$-like orbits can be produced from three Kuiper belt populations tested (i.e. plutinos, twotinos, and Haumea Family) without the presence of an hypothetical planet, while a few similar orbits can be obtained with it; however, the presence of the additional planet produces a wide range of large semimajor-axis / large perihelion objects, in apparent contradiction with the observed scarcity of objects in those regions of phase space. Future studies may determine if there is a connection between the existence of a perihelion gap and a particular orbital configuration of an hypothetical distant planet., Comment: 10 pages, 4 figures, 1 tables, accepted for publication in the ApJ Letters

We present variability measurements and partial light curves of Trans-Neptunian Objects (TNOs) from a two-night pilot study using Hyper Suprime-Cam (HSC) on the Subaru Telescope (Maunakea, Hawai'i, USA). Subaru's large aperture (8-m) and HSC's large field of view (1.77 square degrees) allow us to obtain measurements of multiple objects with a range of magnitudes in each telescope pointing. We observed 65 objects with m_r = 22.6--25.5 mag in just six pointings, allowing 20--24 visits of each pointing over the two nights. Our sample, all discovered in the recent Outer Solar System Origins Survey (OSSOS), span absolute magnitudes H_r = 6.2--10.8 mag and thus investigates smaller objects than previous light curve projects have typically studied. Our data supports the existence of a correlation between light curve amplitude and absolute magnitude seen in other works, but does not support a correlation between amplitude and orbital inclination. Our sample includes a number of objects from different dynamical populations within the trans-Neptunian region, but we do not find any relationship between variability and dynamical class. We were only able to estimate periods for 12 objects in the sample and found that a longer baseline of observations is required for reliable period analysis. We find that 31 objects (just under half of our sample) have variability greater than 0.4 magnitudes during all of the observations; in smaller 1.25 hr, 1.85 hr and 2.45 hr windows, the median variability is 0.13, 0.16 and 0.19 mags, respectively. The fact that variability on this scale is common for small TNOs has important implications for discovery surveys (such as OSSOS or the Large Synoptic Survey Telescope) and color measurements., Comment: 49 pages, 14 figures, 7 tables