Dr. Stephen M. Slivan
MIT, Dept. of Earth, Atmospheric, and Planetary Sciences
These objects are small (diameters less than about 45 km) and too far away to appear as anything but star-like unresolved blots of light in a telescope. However, we can tell that they're irregularly shaped because each object's observed brightness varies as it rotates on its axis, alternately presenting side-on and end-on views. A series of brightness measurements of an asteroid as it rotates is called a rotation lightcurve; most of the Koronis member lightcurve periods known so far are between about 6 hours and 18 hours. With enough lightcurve data it's possible to determine not only the object's rotation period but also its spin axis orientation, the direction of spin about the axis, and a first-order estimate of the object's shape.
Analysis of rotation lightcurves has revealed that the spin vector orientations of several of the largest Koronis family asteroids are unexpectedly aligned in obliquity, which has led to the suggestion that thermal effects might be responsible (more information below). New observations of lightcurves are needed to determine spin vectors of the remaining large Koronis family members, as well those of smaller members and also of a statistical control sample of non-family asteroids. Materials and information at this site have been assembled in support of this ongoing observing program.
Objects in the "Highest priority" list are generally slated for one of several manuscripts in progress to be submitted and published in the refereed literature. Observers who obtain suitable data on such an object may be interested in publishing their work as a co-author of the corresponding manuscript. If so, those data and results should be treated as privileged information and not be published elsewhere, nor should they be made publicly available on the Web. Once the manuscript is submitted the "preprint" version is what's made available to others.
| Last modified 2006 Mar 08 |
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