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Abstract We report the rotational lightcurves of 21 trans-Neptunian objects (TNOs) in Neptune’s 2:1 mean motion resonance obtained with the 6.5 m Magellan-Baade telescope and the 4.3 m Lowell Discovery Telescope. The main survey’s goal is to find objects displaying a large lightcurve amplitude that is indicative of contact binaries or highly elongated objects. In our sample, two 2:1 resonant TNOs showed a significant short-term lightcurve amplitude: 2002 VD130and (531074) 2012 DX98. The full lightcurve of 2012 DX98infers a periodicity of 20.80 ± 0.06 hr and amplitude of 0.56 ± 0.03 mag, whereas 2002 VD130rotates in 9.85 ± 0.07 hr with a 0.31 ± 0.04 mag lightcurve amplitude. Based on lightcurve morphology, we classify (531074) 2012 DX98as a likely contact binary but 2002 VD130as a likely single elongated object. Based on our sample and the lightcurves reported in the literature, we estimate the lower percentage of nearly equal-sized contact binaries at only 7%–14% in the 2:1 resonance, which is comparable to the low fraction reported for the dynamically cold classical TNOs. This low contact binary fraction in the 2:1 Neptune resonance is consistent with the lower estimate of the recent numerical modeling. We report the Sloang′,r′, andi′ surface colors of 2002 VD130, which is an ultra-red TNO whereas 2012 DX98is a very red object based on published surface colors.
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Rotational Study of 5:3 and 7:4 Resonant Objects within the Main Classical Trans-Neptunian Belt
Abstract The 5:3 and 7:4 mean motion resonances of Neptune are at 42.3 and 43.7 au, respectively, and overlap with objects in the classical trans-Neptunian belt (Kuiper Belt). We report the complete/partial lightcurves of 13 and 14 trans-Neptunian objects (TNOs) in the 5:3 and 7:4 resonances, respectively. We report a most likely contact binary in the 7:4 resonance, 2013 FR28, with a periodicity of 13.97 ± 0.04 hr and a lightcurve amplitude of 0.94 ± 0.02 mag. With a V-/U-shaped lightcurve, 2013 FR28has one of the largest well-sampled TNO amplitudes observed with ground-based observations, comparable to the well-determined contact binary 2001 QG298. 2013 FR28has a mass ratioq∼ 1 with a densityρ∼ 1 g cm−3. We find several objects with large amplitudes and classify 2004 SC60, 2006 CJ69, and 2013 BN82as likely contact binaries and 2001 QF331, 2003 YW179, and 2015 FP345as likely elongated objects. We observe the 17:9 resonant or classical object 2003 SP317that we classify as a likely contact binary. A lower estimate of 10%–50% and 20%–55% for the fraction of (nearly) equal-sized contact binaries is calculated in the 5:3 and 7:4 resonances, respectively. Surface colors of 2004 SC60, 2013 BN82, 2014 OL394, and 2015 FP345have been obtained. Including these colors with ones from the literature reveals that elongated objects and contact binaries share the same ultrared surface color, except Manwë–Thorondor and 2004 SC60. Not only are the colors of the 7:4 and 5:3 TNOs similar to the cold classicals, but we demonstrate that the rotational properties of the 5:3 and 7:4 resonants are similar to those of the cold classicals, inferring a clear link between these subpopulations.
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- Award ID(s):
- 2109207
- PAR ID:
- 10498315
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Planetary Science Journal
- Volume:
- 5
- Issue:
- 4
- ISSN:
- 2632-3338
- Format(s):
- Medium: X Size: Article No. 84
- Size(s):
- Article No. 84
- Sponsoring Org:
- National Science Foundation
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