The Spacewatch Wide-Area Survey for Bright Centaurs and Trans-Neptunian Objects
Abstract
We have conducted a large-area search for the brightest members of the trans-Neptunian and Centaur/scattered-disk asteroid populations by reprocessing archival scans from the Spacewatch 0.9 m telescope at Kitt Peak. Our survey encompasses 331 scans taken from 1995 September to 1999 September and has a raw sky coverage of 1483.8 deg2. We discovered five trans-Neptunians and five Centaur/scattered-disk objects using an automated motion detection code. In addition, we serendipitously found four trans-Neptunians and two Centaur/scattered-disk objects that had been previously discovered. This survey is unique in that it involves a method that has a reasonable chance to reacquire its lost objects. In this paper we develop techniques to aid our understanding of our software efficiency and survey procedures. We use this understanding to ``convolve'' our raw sky coverage with our measured detection efficiency and a model of our scan coverage to estimate what fraction of survey areas can be considered ``new.'' Our large sky coverage extends the cumulative luminosity function of the trans-Neptunians into a region previously constrained only by upper limits, and it allows a power-law fit to be attempted to the Centaur cumulative luminosity function. In objects per square degree brighter than R=21.5, we find cumulative surface densities of Centaurs to be 0.017+/-0.011, of trans-Neptunians to be 0.040+/-0.018, and scattered-disk objects to be 0.007+/-0.004. We extrapolate these values to estimate the number of each class in the ecliptic brighter than R=21.5: 100 Centaurs, 400 trans-Neptunians, and 70 scattered-disk objects. Orbit analysis by the Minor Planet Center suggests that three of our five trans-Neptunians are resonators: 1998 VG44 is in the 3:2, 1995 SM55 appears to be in the 5:3, and 1998 SN165 appears to be in the 7:5 resonance.
- Publication:
-
The Astronomical Journal
- Pub Date:
- January 2001
- DOI:
- 10.1086/318022
- Bibcode:
- 2001AJ....121..562L
- Keywords:
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- Kuiper Belt;
- Oort Cloud;
- Minor Planets;
- Asteroids