Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2015
Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2015
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DOI：
10.1007/s10569-017-9805-5
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发表时间：
2018-03-01
影响因子：
1.6
通讯作者：
Williams, I. P.
中科院分区：
文献类型：
--
作者：
Archinal, B. A.;Acton, C. H.;Williams, I. P.
这份报告延续了国际天文学联盟制图坐标和旋转要素工作组大约每三年修订一次关于行星、卫星、小行星和彗星专题的建议的做法。该工作组现已成为天文学联盟的一个“职能工作组”，其成员资格对任何有兴趣参加的人开放。我们描述了提交有关此处所提建议的问题或应用这些建议为特定机构创建新的或更新的坐标系的程序。关于天体方位，已更新了以下天体：水星，根据信使号的结果;火星，沿着精确的经度定义;火卫一;火卫二;（1）谷神星;（52）木卫二;（243）伊达;（2867）斯坦;海王星;（134340）冥王星及其卫星冥卫一;彗星9 P/坦普尔1，19 P/博雷利，67 P/丘留莫夫-格拉西缅科和103 P/哈特利2，注意到这些信息只在特定的时期之间有效。还讨论了与映射67 P/Churyumov-Gerasimenko相关的特殊挑战。为了避免混淆，地球的近似表达式已经被删除，月球方位的低精度系列表达式也被删除。以前网上唯一推荐的（4）灶神星的方向模型是重复的，并解释了它是如何更新的。关于体型，已纳入文本以解释此类信息的预期用途以及所引用不确定性信息的相关性。太阳的大小已经更新，并添加了符号，说明地球和木星的大小和椭圆轴已由IAU决议推荐。天体（这里指的是月球和土卫六）的参考半径在制图用途、正射投影和地球物理用途之间有区别。水星的推荐半径已经根据信使号的结果进行了更新。Titan的推荐半径将返回到其先前值。其他13颗土星卫星的尺寸信息已经更新，并为Aegaeon添加了尺寸信息。冥王星和冥卫一的大小已经更新。（1）谷神星的尺寸信息已经更新，（16）普绪客星和（52）木卫二的尺寸信息已经更新。（25143）Itokawa的大小已被更正。此外，对小天体极点（半球）术语的讨论也作了修改，并增加了对基本方向的讨论。虽然它们继续用于行星及其卫星，但假设行星和行星中心坐标系定义不适用于小天体。然而，根据右手定则，行星中心纬度和小行星纬度和纬度可用于此类天体。我们重申以前的建议，即应规划和努力制作有控制的制图产品;新建议应使用共同的公式确定方位和大小;继续建议就木星和土星的方位模型达成社区共识;最近建议为特定机构编制坐标系的历史摘要，并指出，对于行星和卫星，行星系统在历史上通常优于行星中心系统，并且在过去广泛使用行星坐标的情况下，改用行星中心坐标并没有明显的优势。工作组还要求社区对问题提交过程提供意见，在工作组网站上张贴最新情况，以及是否应就系外行星坐标系提出建议。
This report continues the practice where the IAU Working Group on Cartographic Coordinates and Rotational Elements revises recommendations regarding those topics for the planets, satellites, minor planets, and comets approximately every 3 years. The Working Group has now become a "functional working group" of the IAU, and its membership is open to anyone interested in participating. We describe the procedure for submitting questions about the recommendations given here or the application of these recommendations for creating a new or updated coordinate system for a given body. Regarding body orientation, the following bodies have been updated: Mercury, based on MESSENGER results; Mars, along with a refined longitude definition; Phobos; Deimos; (1) Ceres; (52) Europa; (243) Ida; (2867) Steins; Neptune; (134340) Pluto and its satellite Charon; comets 9P/Tempel 1, 19P/Borrelly, 67P/Churyumov-Gerasimenko, and 103P/Hartley 2, noting that such information is valid only between specific epochs. The special challenges related to mapping 67P/Churyumov-Gerasimenko are also discussed. Approximate expressions for the Earth have been removed in order to avoid confusion, and the low precision series expression for the Moon's orientation has been removed. The previously online only recommended orientation model for (4) Vesta is repeated with an explanation of how it was updated. Regarding body shape, text has been included to explain the expected uses of such information, and the relevance of the cited uncertainty information. The size of the Sun has been updated, and notation added that the size and the ellipsoidal axes for the Earth and Jupiter have been recommended by an IAU Resolution. The distinction of a reference radius for a body (here, the Moon and Titan) is made between cartographic uses, and for orthoprojection and geophysical uses. The recommended radius for Mercury has been updated based on MESSENGER results. The recommended radius for Titan is returned to its previous value. Size information has been updated for 13 other Saturnian satellites and added for Aegaeon. The sizes of Pluto and Charon have been updated. Size information has been updated for (1) Ceres and given for (16) Psyche and (52) Europa. The size of (25143) Itokawa has been corrected. In addition, the discussion of terminology for the poles (hemispheres) of small bodies has been modified and a discussion on cardinal directions added. Although they continue to be used for planets and their satellites, it is assumed that the planetographic and planetocentric coordinate system definitions do not apply to small bodies. However, planetocentric and planetodetic latitudes and longitudes may be used on such bodies, following the right-hand rule. We repeat our previous recommendations that planning and efforts be made to make controlled cartographic products; newly recommend that common formulations should be used for orientation and size; continue to recommend that a community consensus be developed for the orientation models of Jupiter and Saturn; newly recommend that historical summaries of the coordinate systems for given bodies should be developed, and point out that for planets and satellites planetographic systems have generally been historically preferred over planetocentric systems, and that in cases when planetographic coordinates have been widely used in the past, there is no obvious advantage to switching to the use of planetocentric coordinates.The Working Group also requests community input on the question submitting process, posting of updates to the Working Group website, and on whether recommendations should be made regarding exoplanet coordinate systems.