Albedo and atmospheric constraints of dwarf planet Makemake from a stellar occultation

Emilio, M.; Cacella, P.; Giacchini, B.; Pimentel, E.; Smiljanic, R.; Kerber, L. O.; Oliveira, A. S.; Lima, H. J. F.; Colazo, C.; Ortiz, M.; Alonso, M. L.; Bagatin, A. Campo; Harlingten, C.; Marsh, T. R.; Dhillon, V. S.; Hestroffer, D.; Santos-Sanz, P.; Roques, F.; Widemann, T.; Vieira-Martins, R.; Roland, S.; Behrend, R.; Organero, F.; Bruzzone, S.; Salvo, R.; Milone, A.; Weaver, D.; Jacques, C.; Mueller, T.; Licandro, J.; Colas, F.; Maury, A.; Gillon, M.; Lecacheux, J.; Gutiérrez, P. J.; Thirouin, A.; Manfroid, J.; da Silva Neto, D. N.; Colque, J. P.; de La Cueva, I.; Gil-Hutton, R.; Tancredi, G.; Morales, N.; Jehin, E.; Unda-Sanzana, E.; Assafin, M.; Littlefair, S. P.; Camargo, J. I. B.; Ivanov, V. D.; Pinilla-Alonso, N.; Duffard, R.; Lellouch, E.; Alvarez-Candal, A.; Braga-Ribas, F.; Sicardy, B.; Ortiz, J. L.
Bibliographical reference

Nature, Volume 491, Issue 7425, pp. 566-569 (2012).

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11
2012
Journal
Number of authors
56
IAC number of authors
1
Citations
81
Refereed citations
74
Description
Pluto and Eris are icy dwarf planets with nearly identical sizes, comparable densities and similar surface compositions as revealed by spectroscopic studies. Pluto possesses an atmosphere whereas Eris does not; the difference probably arises from their differing distances from the Sun, and explains their different albedos. Makemake is another icy dwarf planet with a spectrum similar to Eris and Pluto, and is currently at a distance to the Sun intermediate between the two. Although Makemake's size (1,420+/-60km) and albedo are roughly known, there has been no constraint on its density and there were expectations that it could have a Pluto-like atmosphere. Here we report the results from a stellar occultation by Makemake on 2011 April 23. Our preferred solution that fits the occultation chords corresponds to a body with projected axes of 1,430+/-9km (1σ) and 1,502+/-45km, implying a V-band geometric albedo pV = 0.77+/-0.03. This albedo is larger than that of Pluto, but smaller than that of Eris. The disappearances and reappearances of the star were abrupt, showing that Makemake has no global Pluto-like atmosphere at an upper limit of 4-12nanobar (1σ) for the surface pressure, although a localized atmosphere is possible. A density of 1.7+/-0.3gcm-3 is inferred from the data.
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Minor Bodies of the Solar System
This project studies the physical and compositional properties of the so-called minor bodies of the Solar System, that includes asteroids, icy objects, and comets. Of special interest are the trans-neptunian objects (TNOs), including those considered the most distant objects detected so far (Extreme-TNOs or ETNOs); the comets and the comet-asteroid
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