The Peculiar Photometric Properties of 2010 WG9: A Slowly Rotating Trans-Neptunian Object from the Oort Cloud
Abstract
We present long-term BVRI observations of 2010 WG9, an ~100 km diameter trans-Neptunian object (TNO) with an extremely high inclination of 70° discovered by the La Silla-QUEST southern sky survey. Most of the observations were obtained with ANDICAM on the SMARTS 1.3 m at Cerro Tololo, Chile from 2010 December to 2012 November. Additional observations were made with EFOSC2 on the 3.5 m NTT telescope of the European Southern Observatory at La Silla, Chile in 2011 February. The observations reveal a sinusoidal light curve with amplitude 0.14 mag and period 5.4955 ± 0.0025 days, which is likely half the true rotation period. Such long rotation periods have previously been observed only for tidally evolved binary TNOs, suggesting that 2010 WG9 may be such a system. We predict a nominal separation of at least 790 km, resolvable with the Hubble Space Telescope and ground-based systems. We measure B - R = 1.318 ± 0.029 and V - R = 0.520 ± 0.018, consistent with the colors of modestly red Centaurs and Damocloids. At I-band wavelengths, we observe an unusually large variation of color with rotational phase, with R - I ranging from 0.394 ± 0.025 to 0.571 ± 0.044. We also measure an absolute R-band absolute magnitude of 7.93 ± 0.05 and solar phase coefficient of 0.049 ± 0.019 mag deg-1.
- Publication:
-
The Astronomical Journal
- Pub Date:
- July 2013
- DOI:
- 10.1088/0004-6256/146/1/17
- arXiv:
- arXiv:1305.5134
- Bibcode:
- 2013AJ....146...17R
- Keywords:
-
- Kuiper Belt: general;
- Kuiper Belt objects: individual: 2010 WG9;
- Oort Cloud;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 17 pages, 5 figures