Shape, size, physical properties and nature of low-perihelion near-Earth asteroid (3200) Phaethon

Hanus, Josef; Delbo, Marco; Vokrouhlicky, David; Pravec, Petr; Emery, Joshua P.; Ali-Lagoa, Victor; Bolin, Bryce T.; Devogele, Maxime; Dyvig, Ron; Galad, Adrian; Jedicke, Robert; Kornos, Leos; Kusnirak, Peter; Licandro, J.; Reddy, Vishnu; Warner, Brian D.; Rivet, Jean-Pierre; Vilagi, Jozef
Referencia bibliográfica

American Astronomical Society, DPS meeting #48, id.#516.08

Fecha de publicación:
10
2016
Número de autores
18
Número de autores del IAC
1
Número de citas
1
Número de citas referidas
1
Descripción
We apply the convex inversion method to the new optical data obtained by six instruments together with the already existing observations and derive convex shape model of low-perihelion near-Earth asteroid (3200) Phaethon. This shape model is then used as an input for the thermophysical modeling. We present new convex shape model and rotational state of Phaethon – sidereal rotation period of 3.603958(2) h and ecliptic coordinates of the preferred pole orientation of (319, ‑39) with a 5 degree uncertainty. Moreover, we derive its size (D=5.1±0.2 km), thermal inertia (Γ=600±200 J m-2s-1/2K-1), geometric visible albedo (pV=0.122±0.008), and estimate the macroscopic surface roughness by the thermophysical model. We also estimate the average size of the surface regolith to few centimeters. The Spitzer emission spectrum of Phaethon is similar to those of CV/CK carbonaceous chondrite meteorites, match with CI/CM carbonaceous chondrites is ruled out. We also study the long-term stability of Phaethon's orbit and spin axis by a numerical orbital and rotation-state integrator. We find that the Sun illumination at the perihelion passage during past thousands of years is not connected to a specific area on the surface implying non-preferential heating. Considering the most important meteor stream of the Geminids is associated with Phaethon, we predict that the meteorites dropped by Geminids are CVs or CKs. We also discuss the possible dynamical link between Phaethon and Pallas and its collisional family.