uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
The rotation state of 67P/Churyumov-Gerasimenko from approach observations with the OSIRIS cameras on Rosetta
Show others and affiliations
2014 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 569, L2- p.Article in journal (Refereed) Published
Abstract [en]

Aims. Approach observations with the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) experiment onboard Rosetta are used to determine the rotation period, the direction of the spin axis, and the state of rotation of comet 67P's nucleus. Methods. Photometric time series of 67P have been acquired by OSIRIS since the post wake-up commissioning of the payload in March 2014. Fourier analysis and convex shape inversion methods have been applied to the Rosetta data as well to the available ground-based observations. Results. Evidence is found that the rotation rate of 67P has significantly changed near the time of its 2009 perihelion passage, probably due to sublimation-induced torque. We find that the sidereal rotation periods P-1 = 12.76129 +/- 0.00005 h and P2 = 12.4043 +/- 0.0007 h for the apparitions before and after the 2009 perihelion, respectively, provide the best fit to the observations. No signs of multiple periodicity are found in the light curves down to the noise level, which implies that the comet is presently in a simple rotation state around its axis of largest moment of inertia. We derive a prograde rotation model with spin vector J2000 ecliptic coordinates lambda = 65 degrees +/- 15 degrees, beta = + 59 degrees +/- 15 degrees, corresponding to equatorial coordinates RA = 22 degrees, Dec = +76 degrees. However, we find that the mirror solution, also prograde, at lambda = 275 degrees +/- 15 degrees, beta = + 50 degrees +/- 15 degrees (or RA = 274 degrees, Dec = +27 degrees), is also possible at the same confidence level, due to the intrinsic ambiguity of the photometric problem for observations performed close to the ecliptic plane.

Place, publisher, year, edition, pages
2014. Vol. 569, L2- p.
Keyword [en]
comets: general, comets: individual: 67P/Churyumov-Gerasimenko, techniques: photometric
National Category
Astronomy, Astrophysics and Cosmology
URN: urn:nbn:se:uu:diva-237625DOI: 10.1051/0004-6361/201424590ISI: 000343092100128OAI: oai:DiVA.org:uu-237625DiVA: diva2:770026
Available from: 2014-12-09 Created: 2014-12-03 Last updated: 2014-12-09Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Davidsson, BjörnRickman, Hans
By organisation
Department of Physics and Astronomy
In the same journal
Astronomy and Astrophysics
Astronomy, Astrophysics and Cosmology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 173 hits
ReferencesLink to record
Permanent link

Direct link