Telescopic and Laboratory Investigations of The Surfaces of Active and Cometary Near Earth Objects

In this Dissertation talk, we present new results from two ongoing projects pertaining to the reflective and material properties of comets and active asteroids among the Near Earth Objects (NEOs). First, we present a new laboratory dataset of reflectance spectra of an increasingly heated sample of the CI Chondrite Orgueil to study how near-Sun / low-perihelion objects might record how they have been thermally altered. This work was inspired by our obtaining the first near-infrared spectrum of (155140) 2005 UD, which found it to be red-sloped and without curvature, unlike its proposed parent (3200) Phaethon. The properties of these near-Sun NEOs provide a clear way to probe how objects with low perihelia (and thus high temperatures) can be altered from their initial states. This work is in revision at the Planetary Science Journal. Secondarily, we present the first near-infrared spectra of the barely-active comet P/2016 BA14 (PanSTARRS) taken during its close approach to the Earth. Despite this object’s very low activity state (and thus evolutionary state), BA14’s reflectance spectrum appears quite similar to that of 67P/C-G after accounting for phase-reddening. A new MCMC-based application of the Near Earth Asteroid Thermal Model (NEATM) retrieves an preliminary albedo of ~2-3% in agreement with what has been concluded from radar observations. This work is in preparation for submission by the meeting. Combining these telescopic case studies, our new laboratory measurements, other work in this Dissertation, and that in the literature, it seems inevitable that there is much greater spectral variability among currently and previously active NEOs, regardless of whether they originate in the Main Belt or trans-Neptunian region.