Anatomy of an Asteroid

Schematic view of asteroid (25143) Itokawa. Credit: ESO. Acknowledgement: JAXA





Asteroid (25143) Itokawa seen in close-up. Credit: JAXA






An additional view of Asteroid (25143) Itokawa seen in close-up. Credit: JAXA


[1] As well as the NTT, brightness measurements from the following telescopes were also used in this work: Palomar Observatory 60-inch Telescope (California, USA), Table Mountain Observatory (California, USA), Steward Observatory 60-inch Telescope (Arizona, USA), Steward Observatory 90-inch Bok Telescope (Arizona, USA), 2-metre Liverpool Telescope (La Palma, Spain), 2.5-metre Isaac Newton Telescope (La Palma, Spain) and the Palomar Observatory 5-metre Hale Telescope (California, USA).

[2] The density of the interior was found to vary from 1.75 to 2.85 grammes per cubic centimetre. The two densities refer to Itokawa’s two distinct parts.

[3] As a simple and rough analogy for the YORP effect, if one were to shine an intense enough light beam on a propeller it would slowly start spinning due to a similar effect.

[4] Lowry and colleagues were the first to observe the effect in action on a small asteroid known as 2000 PH5 (now known as 54509 YORP, see eso0711). ESO facilities also played a crucial role in this earlier study.
