We recently had a successful run of nights on the KPNO 4-m Mayall telescope with the Mosaic camera. These observations are designed to maximize the total number of trans-Neptunian objects discovered with this large field of view camera. We do not schedule followup time for these observations with Mosaic, preferring instead to use smaller field of view instruments and perhaps smaller telescopes once we know where to look. We are proceeding with our own followup efforts but the list of objects is quite long. We invite help from anyone in the community capable of making useful followup observations.
To request objects, contact buie@lowell.edu. Details of object status are available here.
As the floodgates open on KBO detections from mosaic cameras and the concomitant need for retrieval observations becomes acute, we wish to attract your attention toward the discoveries of very faint KBOs that we plan to make this May. Our particular goal is characterize the population beyond 50 AU, where perturbations by the giant planets should have been too weak to disturb the primordial dynamical state. Extensive surveys to R<24 mag have failed to find any KBOs beyond 50 AU, suggesting that we must seek fainter objects to probe the primordial Kuiper Belt. Followup observations of these very faint objects will be particularly difficult, so we are soliciting your efforts or collaboration if you have access to large telescopes.
In May, 1999, we will conduct a survey using the BTC camera at the CTIO 4-meter telescope, which should be complete to R=26 over roughly one square degree of the ecliptic. To date, only a very small area (~0.01 square degree, the Luu & Jewitt Keck data) has been surveyed to this depth. Current N(m) estimates suggest we will detect 30-50 new KBOs at this time, and an unknown number beyond 50 AU.
Retrieval observations and better orbit determinations are as critical to our study of the Kuiper Belt as new object discoveries. Their faintness requires use of either an 8m-class telescope, or a 4m-class telescope with a large enough field of view to facilitate simultaneous retrieval of large numbers of objects. In practice this means access to the Keck, VLT, or Subaru imagers, or the CFHT, KPNO, and CTIO 4m telescopes with mosaic cameras. While we will pursue several avenues toward retrieval resources, it seems prudent to set forth redundant proposals in order to improve our odds of being granted time and getting good weather.
We are able to detect very faint KBOs with the 4-meter CTIO telescope by using the "digital tracking" technique to combine many hours' worth of data (taken over more than one night) into a single image. The large FOV of the BTC mosaic camera permits coverage of large areas of sky in a single run. In May, 1998, we were able to detect 8 KBOs to a limiting magnitude of R=25.4 over 0.5 square degrees of sky, with only 2 nights of observing. All 8 objects were retrieved on images taken 10 nights earlier; the 10-day baseline permits extrapolation of the KBO position to an accuracy of a few arcminutes for most of the following year, sufficient for retrieval with most imagers. The 1998 BTC run was a complete success in that our software was able to find KBOs to the limits predicted by calculations of the Poisson noise limits. We thus have strong faith that our 1999 observations - with more fields, longer integration times, and a broader filter - will reach the goals stated above, if the weather cooperates. The contents of a colloquium describing our method and results may be viewed on my home page (http://www.astro.lsa.umich.edu/users/garyb).
Determinations of useful orbits for the 1999 objects will require a few half-nights per semester on 8m-class telescopes for a year or so, particularly in August 1999 (or earlier) and January 2000. If you are interested in helping fill this potential gap in our own followup capabilities, please contact us for details about field locations, etc. While we will post our discoveries to the MPC promptly, a strong effort toward detection of KBOs at R~26 probably calls for advance coordination of our efforts.
Thank you,
Gary Bernstein, Renu Malhotra, Lynne Allen
For further information, contact garyb@astro.lsa.umich.edu
Austin Albert Mardon
P.O. Box 1223, Main Post Office
Edmonton, Alberta, CANADA
T5J-2M4
email: mardon@freenet.edmonton.ab.ca
Send e-mail to: ekonews@boulder.swri.edu