The Diverse Solar Phase Curves of Distant Icy Bodies. I. Photometric Observations of 18 Trans-Neptunian Objects, 7 Centaurs, and Nereid
The Diverse Solar Phase Curves of Distant Icy Bodies. I. Photometric Observations of 18 Trans-Neptunian Objects, 7 Centaurs, and Nereid
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遥远冰体的不同太阳相位曲线。
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发表时间：
2006
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通讯作者：
S. Tourtellotte
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作者：
D. Rabinowitz;B. Schaefer;S. Tourtellotte
我们已经测量了18个海王星外天体（TNOs），7个半人马座和Nereid的B，V和I的太阳相位曲线，并确定了其中10个目标的旋转曲线。对于每一个天体，我们在整个可见光范围内均匀地进行了1000次观测。我们发现，除了海卫二外，所有目标在小相位角（0.1°-2.0°）处都具有线性相位曲线，相位系数变化范围很大（0.0-0.4 mag deg-1）。在相位角为2°-3°时，半人马座（54598）Bienor和（32532）Thereus的相位曲线变平。最近发现的冥王星尺度天体（2005 FY 9、2003 EL 61和2003 UB 313-现在被称为136199 Eris），与冥王星一样，与大多数TNO相比，具有中性颜色和小相位系数（136199）。这两个特性结合在一起，可能表明大型TNO具有高溶解度，新覆盖的冰面。我们发现几个机构显着波长依赖的相位曲线。TNO（50000）Quaoar、（120348）2004 TY 364和（47932）2000 GN 171具有异常高的I波段相位系数，而在B和V波段具有低得多的系数。它们的相位系数与波长成正比增加0.5-0.8 mag deg-1 μm-1。具有小B波段相位系数（<0.1 mag deg-1）的TNO的相位曲线具有类似但较弱的波长依赖性。相干后向散射是所有这些物体的波长依赖性的可能原因。我们没有看到半人马的这种依赖性，它们的视觉偏差为0.05。
We have measured the solar phase curves in B, V, and I for 18 trans-Neptunian objects (TNOs), 7 Centaurs, and Nereid and determined the rotation curves for 10 of these targets. For each body we have made ∼100 observations uniformly spread over the entire visible range. We find that all the targets except Nereid have linear phase curves at small phase angles (0.1°-2.0°) with widely varying phase coefficients (0.0-0.4 mag deg-1). At phase angles of 2°-3°, the Centaurs (54598) Bienor and (32532) Thereus have phase curves that flatten. The recently discovered Pluto-scale bodies (2005 FY9, 2003 EL61, and 2003 UB313—now known as 136199 Eris), like Pluto, have neutral colors compared to most TNOs and small phase coefficients (≲0.1 mag deg-1). Together, these two properties are a likely indication of large TNOs with high-albedo, freshly coated icy surfaces. We find several bodies with significantly wavelength-dependent phase curves. The TNOs (50000) Quaoar, (120348) 2004 TY364, and (47932) 2000 GN171 have unusually high I-band phase coefficients and much lower coefficients in the B and V bands. Their phase coefficients increase in proportion to wavelength by 0.5-0.8 mag deg-1 μm-1 . The phase curves for TNOs with small B-band phase coefficients (<0.1 mag deg-1) have a similar but weaker wavelength dependence. Coherent backscatter is the likely cause for the wavelength dependence for all these bodies. We see no such dependence for the Centaurs, which have visual albedos of ∼0.05.