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Homogeneity of 67P/Churyumov-Gerasimenko as seen by CONSERT: implication on composition and formation
- Source :
- Astronomy and Astrophysics-A&A, Astronomy and Astrophysics-A&A, EDP Sciences, 2019, 630, A6 (5 p.). ⟨10.1051/0004-6361/201834865⟩
- Publication Year :
- 2019
- Publisher :
- EDP Sciences, 2019.
-
Abstract
- Context. After the landing of Philae, CONSERT probed the nucleus of 67P/Churyumov-Gerasimenko (67P) and observed no heterogeneities at metric scale within the probed part of the small lobe of 67P. Further studies have then quantified the observed homogeneity in terms of maximum permittivity contrast versus the typical size of heterogeneities. Aims. The aim of this article is to interpret the sensitivity limits of CONSERT measurements in terms of composition, and to provide constraints on the maximum variability in composition, porosity, and local dust-to-ice ratio. Methods. The sensitivity of CONSERT measurements to local variations in density, dust-to-ice ratio, and composition was analyzed using permittivity modeling of mixtures. Results. We interpret the maximum detectable heterogeneity size and contrast in terms of composition and porosity of the nucleus. The sensitivity to porosity is ±10 percent points for heterogeneities with a characteristic length scale of a few meters; the sensitivity to local variations in the composition is limited. Conclusions. In terms of accretion, our results are compatible only with scenarios generating porosity heterogeneities at scales lower than one meter, or with porosity variations smaller than ±10 percent points. This is clearly compatible with an accretion model of a gentle gravitational collapse of a pebble cloud.
- Subjects :
- 67P/Churyumov-Gerasimenko
Physics
Permittivity
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]
010504 meteorology & atmospheric sciences
Characteristic length
Homogeneity (statistics)
Mineralogy
Astronomy and Astrophysics
Astrophysics
01 natural sciences
comet
Radar astronomy
Space and Planetary Science
0103 physical sciences
Gravitational collapse
radar astronomy
Porosity
010303 astronomy & astrophysics
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 14320746 and 00046361
- Volume :
- 630
- Database :
- OpenAIRE
- Journal :
- Astronomy & Astrophysics
- Accession number :
- edsair.doi.dedup.....5082aede8bf419f7b109af92f160a387
- Full Text :
- https://doi.org/10.1051/0004-6361/201834865