20000 Varuna - Size

Size

Size estimates for Varuna:
Year Diameter (km) Notes
2001 900 Jewitt
2002 1060 Lellouch
2005 936 Grundy
2005 >621 Spitzer 2-Band
2007 502 Spitzer 1-Band
2010 1003 Chord

The size of the large Kuiper belt objects can be determined by simultaneous observations of thermal emission and reflected sunlight. Unfortunately, thermal measures, intrinsically weak for distant objects, are further hampered by the absorption of the Earth's atmosphere as only the weak 'tail' of the emissions is accessible to Earth-based observations. In addition, the estimates are model-dependent with the unknown parameters (e.g. pole orientation and thermal inertia) to be assumed. Consequently, the estimates of the albedo vary resulting in sometimes substantial differences in the inferred size. Estimates for the size of Varuna have varied from 500 to 1060 km. The two most recent estimates from Spitzer are closer to the 500 kilometres (310 mi) range and inconsistent with the 2005 estimate of a size of 936 +238
−324 km, based on earlier results (900 +129
−145) and (1060 +180
−220). This inconsistency of the Spitzer results with the earlier (sub-millimetre) observations was recently addressed by the original authors (Stansberry et al.); given a number of difficulties in Varuna case, the authors are inclined to favor the sub-millimetre results (Jewitt, Lellouch) for this object over those from Spitzer.

Read more about this topic:  20000 Varuna

Famous quotes containing the word size:

    One writes of scars healed, a loose parallel to the pathology of the skin, but there is no such thing in the life of an individual. There are open wounds, shrunk sometimes to the size of a pin-prick but wounds still. The marks of suffering are more comparable to the loss of a finger, or the sight of an eye. We may not miss them, either, for one minute in a year, but if we should there is nothing to be done about it.
    F. Scott Fitzgerald (1896–1940)

    The obese is ... in a total delirium. For he is not only large, of a size opposed to normal morphology: he is larger than large. He no longer makes sense in some distinctive opposition, but in his excess, his redundancy.
    Jean Baudrillard (b. 1929)

    There are obvious places in which government can narrow the chasm between haves and have-nots. One is the public schools, which have been seen as the great leveler, the authentic melting pot. That, today, is nonsense. In his scathing study of the nation’s public school system entitled “Savage Inequalities,” Jonathan Kozol made manifest the truth: that we have a system that discriminates against the poor in everything from class size to curriculum.
    Anna Quindlen (b. 1952)