ASTEROID LIGHT CURVES from the PALOMAR TRANSIENT FACTORY SURVEY: ROTATION PERIODS and PHASE FUNCTIONS from SPARSE PHOTOMETRY

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/101593

Title:	ASTEROID LIGHT CURVES from the PALOMAR TRANSIENT FACTORY SURVEY: ROTATION PERIODS and PHASE FUNCTIONS from SPARSE PHOTOMETRY
Authors:	章展誥;Waszczak, Adam;Chang, Chan-Kao;Ofek, Eran O.;Laher, Russ;Masci, Frank;Levitan, David;Surace, Jason;Cheng, Yu-Chi;Ip, Wing-Huen;Kinoshita, Daisuke;Helou, George;Prince, Thomas A.;Kulkarni, Shrinivas
Contributors:	理學院天文研究所
Keywords:	ALBEDO;Amplitudes;ASTEROIDS;ASTROPHYSICS, COSMOLOGY AND ASTRONOMY;COLOR;COMPARATIVE EVALUATIONS;DENSITY;DIAGRAMS;Factories;Fittings;GRAVITATION;Industrial plants;Mathematical models;minor planets, asteroids: general;PHOTOMETRY;PLANETS;ROTATION;SPIN;STRESSES;surveys;TRANSIENTS;VISIBLE RADIATION
Date:	2015-09-01
Issue Date:	2026-04-21 14:38:33 (UTC+8)
Publisher:	IOP Publishing Ltd.;United States: The American Astronomical Society
Abstract:	摘要： ABSTRACT We fit 54,296 sparsely sampled asteroid light curves in the Palomar Transient Factory survey to a combined rotation plus phase-function model. Each light curve consists of 20 or more observations acquired in a single opposition. Using 805 asteroids in our sample that have reference periods in the literature, we find that the reliability of our fitted periods is a complicated function of the period, amplitude, apparent magnitude, and other light-curve attributes. Using the 805-asteroid ground-truth sample, we train an automated classifier to estimate (along with manual inspection) the validity of the remaining ∼53,000 fitted periods. By this method we find that 9033 of our light curves (of ∼8300 unique asteroids) have "reliable" periods. Subsequent consideration of asteroids with multiple light-curve fits indicates a 4% contamination in these "reliable" periods. For 3902 light curves with sufficient phase-angle coverage and either a reliable fit period or low amplitude, we examine the distribution of several phase-function parameters, none of which are bimodal though all correlate with the bond albedo and with visible-band colors. Comparing the theoretical maximal spin rate of a fluid body with our amplitude versus spin-rate distribution suggests that, if held together only by self-gravity, most asteroids are in general less dense than ∼2 g cm−3, while C types have a lower limit of between 1 and 2 g cm−3. These results are in agreement with previous density estimates. For 5-20 km diameters, S types rotate faster and have lower amplitudes than C types. If both populations share the same angular momentum, this may indicate the two types' differing ability to deform under rotational stress. Lastly, we compare our absolute magnitudes (and apparent-magnitude residuals) to those of the Minor Planet Center's nominal (G = 0.15, rotation-neglecting) model; our phase-function plus Fourier-series fitting reduces asteroid photometric rms scatter by a factor of ∼3. 其他題名： AJ 其他題名： Astron. J 出版者： United States: The American Astronomical Society 出版日期： 2015-09-01 出處： The Astronomical Journal, 2015-09, Vol.150 (3), p.75--35 資源來源： IoP Science journals 版權： 2015. The American Astronomical Society. All rights reserved. 識別號： ISSN: 0004-6256 識別號： ISSN: 1538-3881 識別號： EISSN: 1538-3881 識別號： DOI: 10.1088/0004-6256/150/3/75
Appears in Collections:	[Graduate Institute of Astronomy] journal & Dissertation

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