Asteroid Watch: 2012 TC4 will Pass Offshore Over Southern Australia - New Update Oct. 5, 2017 - (+Video)

NEW UPDATE: At the time of closest approach, 2012 TC4 will be at high southern declinations.  The space rock  will pass offshore over southern Australia.

2012 TC4 will approach closely enough that tides from Earth may change its spin, and there’s a slim chance that material on its surface and perhaps even its shape could change if the interior is a rubble pile with low cohesive strength.  Astronomers at Goldstone  plan to check for spin changes using radar imaging before and after the closest approach.

The 2017 close approach will bend the asteroid’s trajectory due to Earth’s gravity, and the asteroid’s heliocentric orbit will change. The semimajor axis will increase, the eccentricity will decrease, the inclination will increase, and the orbital period will lengthen.  

2012 TC4 should be detectable at Goldstone from about Oct. 9 – 16, but not at the moment of closest approach, when it will be too far south for Goldstone to track. Scientists plan to observe this object with radar at Goldstone on several dates straddling the close approach.  

A preliminary schedule is available: Oct 9, 10, 11, and 14.  Additional time on Oct. 12 may be added. Radar observations at Arecibo will be possible starting on Oct. 12  at 13:22 UT.

Astronomers have reported a rotation period of 0.2 h and a large lightcurve amplitude of about 1.3 magnitudes.  This indicates that 2012 TC4 is an elongated and rapidly rotating object. 2012 TC4′s absolute magnitude of 26.7 suggests a diameter within a factor of two of 15 meters.  The spectral class is unknown. 

According to NASA: The close approach has generated some buzz on the internet but the chance of an impact in 2017 is zero.

2012 TC4 was discovered by Pan-STARRS 1 on October 4, 2012.   This object was tracked for about seven days during its discovery apparition but was not seen again until late July 2017, when it was recovered by O. Hainaut, D. Koschny, and M. Micheli using the 8.2 m Very Large Telescope in Chile.  

 It will approach within 7.87 Earth radii of Earth’s center (6.87 Earth radii from the surface) on Oct. 12, 2017 at 05:40:44 UT +- 16 s.
https://echo.jpl.nasa.gov/asteroids/2012TC4/tc4_planning.2017.html

Clips, images Credit: NASA, Goldstone Radar