Non-gravitational acceleration in the trajectory of 1I/2017 U1 ('Oumuamua).
In: Nature, Jg. 559 (2018-07-01), Heft 7713, S. 223-226
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Zugriff:
'Oumuamua (1I/2017 U1) is the first known object of interstellar origin to have entered the Solar System on an unbound and hyperbolic trajectory with respect to the Sun 1 . Various physical observations collected during its visit to the Solar System showed that it has an unusually elongated shape and a tumbling rotation state 1-4 and that the physical properties of its surface resemble those of cometary nuclei 5,6 , even though it showed no evidence of cometary activity 1,5,7 . The motion of all celestial bodies is governed mostly by gravity, but the trajectories of comets can also be affected by non-gravitational forces due to cometary outgassing 8 . Because non-gravitational accelerations are at least three to four orders of magnitude weaker than gravitational acceleration, the detection of any deviation from a purely gravity-driven trajectory requires high-quality astrometry over a long arc. As a result, non-gravitational effects have been measured on only a limited subset of the small-body population 9 . Here we report the detection, at 30σ significance, of non-gravitational acceleration in the motion of 'Oumuamua. We analyse imaging data from extensive observations by ground-based and orbiting facilities. This analysis rules out systematic biases and shows that all astrometric data can be described once a non-gravitational component representing a heliocentric radial acceleration proportional to r -2 or r -1 (where r is the heliocentric distance) is included in the model. After ruling out solar-radiation pressure, drag- and friction-like forces, interaction with solar wind for a highly magnetized object, and geometric effects originating from 'Oumuamua potentially being composed of several spatially separated bodies or having a pronounced offset between its photocentre and centre of mass, we find comet-like outgassing to be a physically viable explanation, provided that 'Oumuamua has thermal properties similar to comets.
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Non-gravitational acceleration in the trajectory of 1I/2017 U1 ('Oumuamua).
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Autor/in / Beteiligte Person: | Micheli, M ; Farnocchia, D ; Meech, KJ ; Buie, MW ; Hainaut, OR ; Prialnik, D ; Schörghofer, N ; Weaver, HA ; Chodas, PW ; Kleyna, JT ; Weryk, R ; Wainscoat, RJ ; Ebeling, H ; Keane, JV ; Chambers, KC ; Koschny, D ; Petropoulos, AE |
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Zeitschrift: | Nature, Jg. 559 (2018-07-01), Heft 7713, S. 223-226 |
Veröffentlichung: | Basingstoke : Nature Publishing Group ; <i>Original Publication</i>: London, Macmillan Journals ltd., 2018 |
Medientyp: | academicJournal |
ISSN: | 1476-4687 (electronic) |
DOI: | 10.1038/s41586-018-0254-4 |
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