Absence of an internal magnetic field at Callisto

被引:41
作者
Khurana, KK
Kivelson, MG
Russell, CT
Walker, RJ
Southwood, DJ
机构
[1] UNIV CALIF LOS ANGELES,DEPT EARTH & SPACE SCI,LOS ANGELES,CA 90095
[2] UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,DEPT PHYS,LONDON SW7 2BZ,ENGLAND
关键词
D O I
10.1038/387262a0
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Little is known about the internal properties of Callisto-the outermost of Jupiter's four large galilean moons-other than the average density (about 1.8 cm(-3)). The recent unexpected discovery(1-4) that Ganymede, and perhaps Io, has an internally generated magnetic field, combined with gravity results(5,6) suggesting that both Ganymede and Io are internally differentiated with metallic cores and rocky mantles, has heightened anticipation of the results obtained by the Galileo spacecraft in its recent fly-by of Callisto. Here we report that the spacecraft, passing the moon at a distance of only similar to 1,100 km from the surface, detected only a small enhancement of the field strength (similar to 7 nT), which may be related to changes in the jovian plasma environment caused by Callisto(7). Callisto does not have an internally generated magnetic field.
引用
收藏
页码:262 / 264
页数:3
相关论文
共 18 条
[1]   Gravitational constraints on the internal structure of Ganymede [J].
Anderson, JD ;
Lau, EL ;
Sjogren, WL ;
Schubert, G ;
Moore, WB .
NATURE, 1996, 384 (6609) :541-543
[2]   Gravitational evidence for an undifferentiated Callisto [J].
Anderson, JD ;
Lau, EL ;
Sjogren, WL ;
Schubert, G ;
Moore, WB .
NATURE, 1997, 387 (6630) :264-266
[3]   ON THE INJECTION AND SCATTERING OF PROTONS IN JUPITERS MAGNETOSPHERE [J].
BARBOSA, DD .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 1981, 86 (NA11) :8981-8990
[4]  
Belcher J. W., 1983, Physics of the Jovian Magnetosphere, P68
[5]   DIAMAGNETIC SOLAR-WIND CAVITY DISCOVERED BEHIND MOON [J].
COLBURN, DS ;
CURRIE, RG ;
MIHALOV, JD ;
SONETT, CP .
SCIENCE, 1967, 158 (3804) :1040-&
[6]  
Dessler A. J., 1983, Coordinate systems. Physics of the Jovian magnetosphere, P498, DOI 10.1017/CBO9780511564574.016
[7]   Plasma observations at Io with the Galileo spacecraft [J].
Frank, LA ;
Paterson, WR ;
Ackerson, KL ;
Vasyliunas, VM ;
Coroniti, FV ;
Bolton, SJ .
SCIENCE, 1996, 274 (5286) :394-395
[8]   Absence of a magnetic-field signature in plasma-wave observations at Callisto [J].
Gurnett, DA ;
Kurth, WS ;
Roux, A ;
Bolton, SJ .
NATURE, 1997, 387 (6630) :261-262
[9]   Evidence for a magnetosphere at Ganymede from plasma-wave observations by the Galileo spacecraft [J].
Gurnett, DA ;
Kurth, WS ;
Roux, A ;
Bolton, SJ ;
Kennel, CF .
NATURE, 1996, 384 (6609) :535-537
[10]  
KIVELSON MG, 1992, SPACE SCI REV, V60, P357, DOI 10.1007/BF00216862