Thermal disruption of NEAs: Experimental results based on CI asteroid simulants

Over the past few years, the activity displayed by near-Earth asteroids has become the focal point of a considerable number of studies. From NEA population models ( e.g. Granvik et al. 2016), observational results (e.g. Jewitt et al. 2013, Wiegert et al. 2020, Lauretta et al. 2019), numerical investigations (e.g. Molaro et al. 2020), and experimental efforts (e.g. Delbo et al. 2014, Masiero et al. 2021) it is evident that the activity of NEAs, and more specifically the thermally-driven component, can provide useful insights on physical properties such as the bulk composition and internal structure of these objects.

We present experiments using the Space and High Irradiance Near-Sun Simulator (SHINeS; Tsirvoulis et al. 2022), where we study the effects of direct insolation at high intensity, simulating the solar irradiance at heliocentric distances in the range from 0.08 to 0.23 AU, on CI-type asteroid simulant material (Britt et al. 2019). We demonstrate that immediate erosion can take place under these circumstances, without the need of prior weakening of the material via other mechanisms such as crack growth over many heating cycles or micrometeoroid impacts. Furthermore, to assess the efficacy of the observed disruption process to lead to mass-loss from an asteroid surface, we developed particle-velocimetry algorithms that allow us to analyse high-speed footage of the experiments, and reconstruct the three-dimensional velocity field of the ejected particles.

With these methods we are able to examine the nature of the disruption mechanisms, and the rates of surface erosion and mass-loss as a function of the simulated heliocentric distance, in an effort to understand the effectiveness of direct thermal disruption of NEAs during their perihelion passages.

References:

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3) Wiegert, P. et al.: Supercatastrophic Disruption of Asteroids in the Context of SOHO Comet, Fireball, and Meteor Observations. AJ 159(4), 143 (2020).
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