Spin State of Returning Fly-by Near Earth Asteroid 2012 TC4
Abstract
The ten-meter class near-Earth asteroid 2012 TC4 will make a close approach to the Earth on October 12, 2017. As of July 2017, the close approach distance ranges from 0.003 to 0.64 lunar distances (LD) with a nominal value of 0.23 LD. However this is the second observable close approach that this object has made since its discovery. In particular, broadband photometry was obtained for 2012 TC4 on 10 and 11 October 2012 using the Magdalena Ridge Observatory (MRO) 2.4-meter telescope. A periodicity of ~12.2 minutes was immediately evident in the time-series data, which was in agreement with the reported values of Polishook (2013), Odden et al. (2012), Warner (2013), and Carbognani (2014). The lightcurve displays an amplitude of ~0.9 magnitude, which implies that it is highly elongated with an axial ratio of a/b>2.3. However, a second period is also clearly evident in the MRO data, indicating that the asteroid is in a state of non-principle axis rotation.The nature of its orbit has made 2012 TC4 an attractive Earth-impacting asteroid surrogate for an exercise testing the capabilities of the scientific and emergency response communities (Reddy, 2017). For this reason, it is anticipated that considerable resources, including MRO, will be utilized to take advantage of the 2017 flyby to study this asteroid. Here, we present the details of the tumbling nature of this fast-spinning object observed during the October 2012 discovery apparition. These data were acquired before closest approach in 2012 where the asteroid came within 0.25 lunar distances of Earth. Therefore, this analysis will be discussed in the context of the spin state observations planned for early October 2017 at MRO, for which preliminary results will also be reported. In particular, comparison of the observed rotation state from the two apparitions can be indicative of any effects of Earth’s gravity during the 2012 flyby.References:Odden, C.E., Verhaegh, J.C., McCullough, D.G., and Briggs, J.W. (2013). Minor Planet Bul. 40, 176-177.Warner, B.D. (2013). Minor Planet Bul. 40, 71-80.Polishook, D. (2013). Minor Planet Bul. 40, 42-43.Carbognani, A. (2014). Minor Planet Bul. 41, 4-8.Reddy, V. (2017), AMOS SSA Technical Conference, Maui, HI.
- Publication:
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AAS/Division for Planetary Sciences Meeting Abstracts #49
- Pub Date:
- October 2017
- Bibcode:
- 2017DPS....4920406R