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Abstract The trans-Neptunian object (58534) 1997 CQ₂₉(a.k.a. Logos) is a resolved wide binary in the dynamically Cold Classical population. With Hubble Space Telescope resolved observations where the primary Logos is well separated from its secondary Zoe it can be established that Logos has a time-variable brightness. Logos’ brightness varied by several tenths of a magnitude over a short timescale of hours while the brightness variability of Zoe was on a longer timescale. New unresolved ground-based observations obtained with the Lowell Discovery Telescope and the Magellan-Baade telescope confirm at least one highly variable component in this system. With our ground-based observations and photometric constraints from space-based observations, we suggest that the primary Logos is likely a close/contact binary whose rotational period is 17.43 ± 0.06 hr for a lightcurve amplitude of 0.70 ± 0.07 mag, while Zoe is potentially a (very) slow rotator with an unknown shape. Using theCandelasoftware, we model the Logos-Zoe system and predict its upcoming mutual events season using rotational, physical, and mutual orbit parameters derived in this work or already published. Zoe’s shape and rotational period are still uncertain, so we consider various options to better understand Zoe. The upcoming mutual event season for Logos-Zoe starts in 2026 and will last for four years with up to two events per year. Observations of these mutual events will allow us to significantly improve the physical and rotational properties of both Logos and Zoe. 

Abstract We present here the design, architecture, and first data release for the Solar System Notification Alert Processing System (SNAPS). SNAPS is a solar system broker that ingests alert data from all-sky surveys. At present, we ingest data from the Zwicky Transient Facility (ZTF) public survey, and we will ingest data from the forthcoming Legacy Survey of Space and Time (LSST) when it comes online. SNAPS is an official LSST downstream broker. In this paper we present the SNAPS design goals and requirements. We describe the details of our automatic pipeline processing in which the physical properties of asteroids are derived. We present SNAPShot1, our first data release, which contains 5,458,459 observations of 31,693 asteroids observed by ZTF from 2018 July to 2020 May. By comparing a number of derived properties for this ensemble to previously published results for overlapping objects we show that our automatic processing is highly reliable. We present a short list of science results, among many that will be enabled by our SNAPS catalog: (1) we demonstrate that there are no known asteroids with very short periods and high amplitudes, which clearly indicates that in general asteroids in the size range 0.3–20 km are strengthless; (2) we find no difference in the period distributions of Jupiter Trojan asteroids, implying that the L4 and L5 clouds have different shape distributions; and (3) we highlight several individual asteroids of interest. Finally, we describe future work for SNAPS and our ability to operate at LSST scale. 

Abstract The long‐term stability of coastal wetlands is determined by interactions among sea level, plant primary production, sediment supply, and wetland vertical accretion. Human activities in watersheds have significantly altered sediment delivery from the landscape to the coastal ocean, with declines along much of the U.S. East Coast. Tidal wetlands in coastal systems with low sediment supply may have limited ability to keep pace with accelerating rates of sea‐level rise (SLR). Here, we show that rates of vertical accretion and carbon accumulation in nine tidal wetland systems along the U.S. East Coast from Maine to Georgia can be explained by differences in the rate of relative SLR (RSLR), the concentration of suspended sediments in the rivers draining to the coast, and temperature in the coastal region. Further, we show that rates of vertical accretion have accelerated over the past century by between 0.010 and 0.083 mm yr⁻², at roughly the same pace as the acceleration of global SLR. We estimate that rates of carbon sequestration in these wetland soils have accelerated (more than doubling at several sites) along with accelerating accretion. Wetland accretion and carbon accumulation have accelerated more rapidly in coastal systems with greater relative RSLR, higher watershed sediment availability, and lower temperatures. These findings suggest that the biogeomorphic feedback processes that control accretion and carbon accumulation in these tidal wetlands have responded to accelerating RSLR, and that changes to RSLR, watershed sediment supply, and temperature interact to determine wetland vulnerability across broad geographic scales.