(47171) 1999 TC 36, A transneptunian triple
Abstract
We present new analysis of HST images of (47171) 1999 TC 36 that confirm it as a triple system. Fits to the point-spread function (PSF) consistently show that the apparent primary is itself composed of two similar-sized components. The two central components, A1 and A2, can be consistently identified in each of nine epochs spread over 7 years of time. In each instance, the component separation, ranging from 0.023 ± 0.002 to 0.031 ± 0.003 arcsec, is roughly one half of the Hubble Space Telescope's diffraction limit at 606 nm. The orbit of the central pair has a semi-major axis of a ∼ 867 km with a period of P ∼ 1.9 days. These orbital parameters yield a system mass that is consistent with M sys = 12.75 ± 0.06 × 10 18 kg derived from the orbit of the more distant secondary, component B. The diameters of the three components are d=286-38+45km,d=265-35+41kmandd=139-18+22km. The relative sizes of these components are more similar than in any other known multiple in the Solar System. Taken together, the diameters and system mass yield a bulk density of ρ=542-211+317kgm. HST photometry shows that component B is variable with an amplitude of ⩾0.17 ± 0.05 magnitudes. Components A1 and A2 do not show variability larger than 0.08 ± 0.03 magnitudes approximately consistent with the orientation of the mutual orbit plane and tidally distorted equilibrium shapes. The system has high specific angular momentum of J/ J' = 0.93, comparable to most of the known transneptunian binaries.
- Publication:
-
Icarus
- Pub Date:
- June 2010
- DOI:
- 10.1016/j.icarus.2009.12.017
- arXiv:
- arXiv:0912.2074
- Bibcode:
- 2010Icar..207..978B
- Keywords:
-
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 16 pages, 8 figures, 6 tables. Accepted to Icarus