DPS 35th Meeting, 1-6 September 2003
Session 39. KBO and Centaurs II
Poster, Highlighted on, Friday, September 5, 2003, 3:30-6:00pm, Sierra Ballroom I-II

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[39.21] HST Photometry of trans-Neptunian Objects

D.C. Stephens, K.S. Noll (STScI), W.M. Grundy, R.L. Millis, J. Spencer, M. Buie (Lowell), S.C. Tegler (NAU), W. Romanishin (U. OK), D.P. Cruikshank (NASA/Ames)

Trans-Neptunian Objects (TNOs) display a large range of colors from just blue of solar to extremely red, which suggests variations in the surface composition of these bodies that may be due to their orbital evolution. Correlations between the orbital parameters and colors of TNOs may help identify whether the range of colors is due to compositional differences and/or resurfacing effects. We will present the correlations with color that have been reported for the trans-Neptunian objects (TNOs) and discuss the relevance of using Spearman rank correlations and similar tests to identify and interpret trends between colors and orbital parameters. Using V, R, and I photometry obtained with the WFPC2 instrument on HST, we will show that Spearman rank correlations do not exist for any combination of orbital parameter with V-I, V-R, and R-I. However, while rank correlations do not exist, trends in color similar to those observed for the B-band colors do occur.

Extensive modeling, multi-wavlength observations, and accurate determinations of the albedos of TNOs will all be required to determine if the diversity in color observed for the TNOs is due to collisional resurfacing, excessive irradiation, compositional differences, or a combination of the three. The significance of the HST results presented here will be enhanced in the future by the inclusion of near-infrared J and H magnitudes, and albedo measurements from SIRTF. When combined, this data will help identify objects with different surface compositions, and ascertain whether the gray surfaces of TNOs are due to extensive irradiation or resurfacing. We will then be able to better identify the sources responsible for the diversity of TNO colors.

This research is supported by grants to STScI: GO-9060, GO-9386

If you would like more information about this abstract, please follow the link to http://www.stsci.edu/~stephens/tnophot.html. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: stephens@stsci.edu

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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.