Welcome to the website for the 2012 TC4 Observing Campaign. Our intention is to provide a central clearinghouse for basic information about the near Earth asteroid 2012 TC4 and about the observations that will be obtained during its upcoming apparition.

This site will contain background information about 2012 TC4, a list of observations that are planned/scheduled/obtained, and status reports on the events leading up to the close approach. We will also produce an email list where updates can be broadcast to subscribers.

What is special about 2012 TC4?

2012 TC4 is a near-Earth asteroid discovered in 2012
It has the potential to get very close to the Earth. There is significant interest in observing it this fall to improve its orbit so that future Earth encounters can be investigated.
2012 TC4 makes a very close approach to the Earth this fall
On 12 Oct 2017, it will pass within the orbit of the Moon, At closest approach, it will be ~50,000 km from Earth.
Observing conditions vary through the encounter
During its approach to the Earth, the observing conditions are good (near opposition for ~2 months, with Earth-facing surface mostly illuminated). After passing the Earth, however, it will be difficult to observe (small solar elongation, with most of the Earth-facing surface in shadow).

NASA Bulletins

2012 TC4 NASA Notification - Recovery - Exercise

2012 TC4 NASA Notification - Close Approach in 2 Weeks - Exercise

Updates & News

2019.06.21: The supplemental lightcurve data from Reddy et al., 2019 is available.

2018.02.06: TC4 Campaign Results & NEOO Program Annual Review, 14-16 February 2018, Tucson, AZ.

2017.10.16: New orbit solution precludes any Earth impact for the next 100 years. Orbit solution JPL#56, which included radar astrometry and close encounter optical data, has ruled out any impact with the Earth in the next 100 years. As of 16 Oct 2017, 2012 TC4 has been removed from the Sentry: Impact Monitoring List.

2017.10.13: lots of updates! Properties, new images and movies,...

2017.10.11: Two movies showing 2012 TC4 moving across the sky have been obtained. In both movies, the asteroid can be seen getting brighter and fainter, exhibiting its rapid rotation rate.

One was obtained by Ryou Ohsawa and collaborators at the Kiso observatory in Japan on Oct. 10 and 11, using a newly developed CMOS camera. It is available here.

The other is seen here, or enlarged on the Gallery Page.

Animated GIF of 2012 TC4 moving across the sky. Details: 2012 TC4 moving across the sky on Oct 11, 2017

Credit: Alberto Quijano Vodniza and Mario Rojas Pereira, University of Narino Observatory, Colombia

2017.09.29: New orbit solution precludes an Earth impact in 2050. Solution JPL#46 has refined the orbit precisely enough to show that the asteroid's passage in October will miss the critical keyhole that would have altered its orbit into one that would impact the Earth in 2050. Potential impacts farther in the future have not been ruled out. See Orbit page for more details.

2017.09.05: 2012 TC4 recovery confirmed by Spacewatch on Aug 30-31! See Current Status page for details and further updates.

2017.08.06: 2012 recovered by VLT observers!

2012 TC4 observed Credit: ESO / ESA NEOCC / Olivier Hainaut (ESO), Marco Micheli (ESA) and Detlef Koschny (ESA) Details: 2012 TC4 observed (annotated)

Credit: ESO / ESA NEOCC / Olivier Hainaut (ESO), Marco Micheli (ESA) and Detlef Koschny (ESA)

Related releases:
A Very Close Encounter