Confirmation of the Sublimation Activity of the Primitive Main-Belt Asteroids 779 Nina, 704 Interamnia, and 145 Adeona, as well as its Probable Spectral Signs on 51 Nemausa and 65 Cybele

Abstract

Abstract: This paper presents the results that confirm the sublimation activity at the perihelion of the primitive main-belt asteroids 779 Nina, 704 Interamnia, and 145 Adeona; this activity was first discovered in September 2012 (Busarev et al., 2015; Busarev et al., 2016). The new spectrophotometric and/or UBVRI photometric observations of Nina, Interamnia, and Adeona were carried out in 2016–2018 during a regular perihelion passage of these asteroids. Additionally, probable spectral signs of weak sublimation activity were discovered on another two primitive main-belt asteroids, 51 Nemausa and 65 Cybele. In this study, we discuss the conditions for the occurrence of a periodic and/or continuous sublimation process on main-belt asteroids with low-temperature mineralogy; in particular, the conditions that are associated with their formation close to the “snow line” or beyond. We also consider general evolution processes that are able sustain a sufficiently high concentration of water ice close to the surface of the bodies in question and, therefore, their continuous sublimation activity, or lead to the recurrence of extinct activity.