The Rotation Axis of the Centaur 5145 Pholus

✍ Scribed by Tony L. Farnham

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 83 KB
• Volume: 152
• Category: Article
• ISSN: 0019-1035
• DOI: 10.1006/icar.2001.6656

✦ Synopsis

We present observations of the Centaur 5145 Pholus from January 2000 to August 2000. A rotational lightcurve was assembled from both V and R measurements, confirming previous period determinations of 0.416 day but exhibiting an amplitude over twice as high as previously measured. This lightcurve was then used in conjunction with previously published lightcurves to solve for a north pole position of λ 0 = 149 • , β 0 = +26 • (prograde rotation), and a sidereal period of 0.4159256 ± 0.0000016 day. As part of this analysis, the axial ratios of Pholus were found to be a/b = 1.8 and b/c = 1.0. Color analyses of the data give an average V -R color of 0.71 ± 0.03, which is slightly lower than the 0.75-0.84 range previously seen. This difference, combined with the fact that we see color variations as a function of rotation, suggest that Pholus' northern hemisphere contains bluer features than are seen in its southern hemisphere.