10
July 2003
Pluto's atmosphere: The pressure builds
Opportunities to examine Pluto's atmosphere are rare. It's the only planet in the Solar System not yet visited by a spacecraft — though NASA's New Horizons probe may rectify that situation some time around 2016. Meanwhile astronomers have to wait for stellar occultations, when a planet's atmosphere can be probed by watching what happens to starlight that passes through it. Pluto's tenuous atmosphere was first detected during an occultation in 1985, and another in 1988 provided more details. Occultations occurred in July and August last year, and two groups report observations of those events at various wavelengths. There have been big changes. The predominantly nitrogen atmosphere has expanded, with atmospheric pressure doubling in the intervening 14 years, probably a seasonal effect as Pluto proceeds on its 248 (Earth) year orbit of the Sun.
The recent expansion of Pluto's atmosphere
J. L. ELLIOT , A. ATES, B. A. BABCOCK, A. S. BOSH, M. W. BUIE,
K. B. CLANCY, E. W. DUNHAM, S. S. EIKENBERRY, D. T. HALL, S. D. KERN, S. K. LEGGETT,
S. E. LEVINE, D.-S. MOON, C. B. OLKIN, D. J. OSIP, J. M. PASACHOFF, B. E. PENPRASE,
M. J. PERSON, S. QU, J. T. RAYNER, L. C. ROBERTS JR, C. V. SALYK, S. P. SOUZA,
R. C. STONE, B. W. TAYLOR, D. J. THOLEN, J. E. THOMAS-OSIP, D. R. TICEHURST &
L. H. WASSERMAN
Nature 424, 165–168 (2003); doi:10.1038/nature01762
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Large changes in Pluto's atmosphere as revealed by recent
stellar occultations
B. SICARDY, T. WIDEMANN, E.
LELLOUCH, C. VEILLET, J.-C. CUILLANDRE, F. COLAS, F. ROQUES, W. BEISKER, M. KRETLOW,
A.-M. LAGRANGE, E. GENDRON, F. LACOMBE, J. LECACHEUX, C. BIRNBAUM, A. FIENGA,
C. LEYRAT, A. MAURY, E. RAYNAUD, S. RENNER, M. SCHULTHEIS, K. BROOKS, A. DELSANTI,
O. R. HAINAUT, R. GILMOZZI, C. LIDMAN, J. SPYROMILIO, M. RAPAPORT, P. ROSENZWEIG,
O. NARANJO, L. PORRAS, F. D�AZ, H. CALDER�N, S. CARRILLO, A. CARVAJAL, E. RECALDE,
L. GAVIRIA CAVERO, C. MONTALVO, D. BARR�A, R. CAMPOS, R. DUFFARD & H. LEVATO
Nature 424, 168–170 (2003); doi:10.1038/nature01766
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Planetary science: Pluto's atmospheric surprise
WILLIAM HUBBARD
Last year, for the first time in 14 years,
an alignment of stars with Pluto created an opportunity to observe the atmosphere
of this most remote of planets. Though tenuous, the atmosphere has, remarkably,
expanded.
Nature 424, 137–138 (2003); doi:10.1038/424137a
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