Stardust-NExT, Deep Impact, and the accelerating spin of 9P/Tempel 1

CORC > 云南天文台 > 中国科学院云南天文台 > 丽江天文观测站（南方基地）

	Stardust-NExT, Deep Impact, and the accelerating spin of 9P/Tempel 1
	Belton, MJS; Meech, KJ; Chesley, S; Pittichova, J; Carcich, B; Drahus, M; Harris, A; Gillam, S; Veverka, J; Mastrodemos, N
刊名	ICARUS
	2011-05
卷号	213 期号:1 页码:345-368
关键词	Comets Comets, Nucleus Rotational dynamics Comet Tempel 1
ISSN号	0019-1035
通讯作者	Belton, MJS (reprint author), Belton Space Explorat Initiat LLC, 430 S Randolph Way, Tucson, AZ 85716 USA.
产权排序	第九完成单位
英文摘要	The evolution of the spin rate of Comet 9P/Tempel 1 through two perihelion passages (in 2000 and 2005) is determined from 1922 Earth-based observations taken over a period of 13 year as part of a World-Wide observing campaign and from 2888 observations taken over a period of 50 days from the Deep Impact spacecraft. We determine the following sidereal spin rates (periods): 209.023 +/- 0.025 degrees/dy (41.335 +/- 0.005 h) prior to the 2000 perihelion passage, 210.448 +/- 0.016 degrees/dy (41.055 +/- 0.003 h) for the interval between the 2000 and 2005 perihelion passages, 211.856 +/- 0.030 degrees/dy (40.783 +/- 0.006 h) from Deep Impact photometry just prior to the 2005 perihelion passage, and 211.625 +/- 0.012 degrees/dy (40.827 +/- 0.002 h) in the interval 2006-2010 following the 2005 perihelion passage. The period decreased by 16.8 +/- 0.3 min during the 2000 passage and by 13.7 +/- 0.2 min during the 2005 passage suggesting a secular decrease in the net torque. The change in spin rate is asymmetric with respect to perihelion with the maximum net torque being applied on approach to perihelion. The Deep Impact data alone show that the spin rate was increasing at a rate of 0.024 +/- 0.003 degrees/dy/dy at JD2453530.60510 (i.e., 25.134 dy before impact), which provides independent confirmation of the change seen in the Earth-based observations. The rotational phase of the nucleus at times before and after each perihelion and at the Deep Impact encounter is estimated based on the Thomas et al. (Thomas et al. [2007]. Icarus 187, 4-15) pole and longitude system. The possibility of a 180 error in the rotational phase is assessed and found to be significant. Analytical and physical modeling of the behavior of the spin rate through of each perihelion is presented and used as a basis to predict the rotational state of the nucleus at the time of the nominal (i.e., prior to February 2010) Stardust-NExT encounter on 2011 February 14 at 20:42. We find that a net torque in the range of 0.3-2.5 x 10(7) kg m(2) s(-2) acts on the nucleus during perihelion passage. The spin rate initially slows down on approach to perihelion and then passes through a minimum. It then accelerates rapidly as it passes through perihelion eventually reaching a maximum post-perihelion. It then decreases to a stable value as the nucleus moves away from the Sun. We find that the pole direction is unlikely to precess by more than similar to 1 degrees per perihelion passage. The trend of the period with time and the fact that the modeled peak torque occurs before perihelion are in agreement with published accounts of trends in water production rate and suggests that widespread H(2)O out-gassing from the surface is largely responsible for the observed spin-up. (C) 2011 Elsevier Inc. All rights reserved.
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	SPACE-TELESCOPE OBSERVATIONS ; PERIOD DETERMINATION ; COMET 9P/TEMPEL-1 ; EJECTA PLUME ; NUCLEUS ; COMET-9P/TEMPEL-1 ; EVOLUTION ; ROTATION ; MISSION ; HALLEY
收录类别	SCI
原文出处	http://www.sciencedirect.com/science/article/pii/S0019103511000078?np=y
语种	英语
WOS记录号	WOS:000290190100021
内容类型	期刊论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/5411]
专题	云南天文台_丽江天文观测站（南方基地）
推荐引用方式 GB/T 7714	Belton, MJS,Meech, KJ,Chesley, S,et al. Stardust-NExT, Deep Impact, and the accelerating spin of 9P/Tempel 1[J]. ICARUS,2011,213(1):345-368.
APA	Belton, MJS.,Meech, KJ.,Chesley, S.,Pittichova, J.,Carcich, B.,...&Zhao, H.(2011).Stardust-NExT, Deep Impact, and the accelerating spin of 9P/Tempel 1.ICARUS,213(1),345-368.
MLA	Belton, MJS,et al."Stardust-NExT, Deep Impact, and the accelerating spin of 9P/Tempel 1".ICARUS 213.1(2011):345-368.