Mars: A possible discrepancy between the radio spectrum and elementary theory

Epstein, E. E.

doi:10.1016/0019-1035(71)90057-1

Cited by 16 publications

(6 citation statements)

References 34 publications

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“…The two brightness temperatures measured in 1967 are in good agreement with previously published data, which indicate that the Martian brightness temperature at wavelengths between 1 and 21 cm is approximately 190°K (Hobbs, McCullough, and Waak, 1968). The weighted average of the 1.85-and 3.75-cm temperatures reported in this paper is 193" f 10°K.…”

Section: Resultsand Conclusionsupporting

confidence: 91%

“…However, these new measurements should help define the microwave spectrum of Mars more accurately. The importance of determining the radio spectrum has recently been emphasized by Epstein (1971), who suggests that measurements of the brightness temperature at millimeter wavelengths do not tend to conform to the spectra predicted by theoretical models. Thus the proper interpretation of the microwave spectrum may reveal new information about the properties of the Martian surface.…”

Section: Resultsand Conclusionmentioning

confidence: 99%

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Mars: Measurements of its brightness temperature at 1.85 and 3.75 cm wavelength

Klein

1971

Icarus

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Section: Resultsand Conclusionsupporting

confidence: 91%

Section: Resultsand Conclusionmentioning

confidence: 99%

Mars: Measurements of its brightness temperature at 1.85 and 3.75 cm wavelength

Klein

1971

Icarus

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“…For convenience, we summarize our findings for these sources in Table 7. Our brightness temperature for Mars has been corrected from a mean heliocentric radius of 1.658 AU for the epochs of observation to a fiducial heliocentric radius of 1.524 AU using an r 0.25 law (Epstein, 1971) to facilitate comparison with other measurements. In this table we have adopted the more precise Leitch (1998) values for S 3c286 /S cas and T Jup /S cas .…”

Section: Epoch Datesmentioning

confidence: 99%

An Absolute Flux Density Measurement of the Supernova Remnant Cassiopeia A at 32 GH[CLC]z[/CLC]

Mason¹,

Leitch²,

Myers³

et al. 1999

The Astronomical Journal

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We report 32 GHz absolute flux density measurements of the supernova remnant Cas A, with an accuracy of 2.5%. The measurements were made with the 1.5-meter telescope at the Owens Valley Radio Observatory. The antenna gain had been measured by NIST in May 1990 to be 0.505 ± 0.007 mK Jy . Our observations of Cas A in May 1998 yield S cas,1998 = 194 ± 5 Jy. We also report absolute flux density measurements of 3C48, 3C147, 3C286, Jupiter, Saturn and Mars.Subject headings: standards -ISM: individual (Cassiopeia A) -planets and satellites: individual (Jupiter, Mars, Saturn) -quasars: individual (3C48, 3C147, 3C273, 3C286, 3C345) -galaxies: individual (3C84, 3C218, 3C353)

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“…Density sc on equation shown in figure 2. Sagan & Veverka (1971) and Cuzzi & Muhleman (1972) have discussed the microwave temperature spectrum (illustrated in figure 11 after Epstein (1971)), showing a reasonably good fit to the data by a dielectric sphere of dielectric constant of 2.5 and very low loss. Sagan & Veverka (1971) note, however, that within the data set, a model could also be fitted (and possibly required to fit the data) which has a layer of 30 pm of precipitated water on the surface of Mars.…”

Section: Arsmentioning

confidence: 85%

“…Dashed line is for a two-layer model (1 m, K = 1.5 overlying a half-space Figure11. Brightness temperature against wavelength for Mars (fromEpstein 1971). Dashed line is the mode for a uniform dielectric sphere with K = 2.5.…”

mentioning

confidence: 99%

Electrical properties of planetary surfaces

Strangway

Olhoeft

1977

Phil. Trans. R. Soc. Lond. A

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The electrical properties of the lunar surface are those of very good dielectric insulators. The results of the Apollo programme and laboratory studies on lunar samples have confirmed the predictions of Earth-based and spacecraft measurements of the dielectric properties of the lunar surface, and helped to increase the reliability of such studies of the surfaces of other planetary bodies. It appears that the electrical properties of the surfaces of Mercury, Venus and Mars are all very similar to those found for the Moon. Mercury has no atmosphere and in this sense is very similar to the Moon; Mars has a mean atmospheric pressure and temperature at the surface that is far below the triple point of water; while Venus has surface temperatures and pressures that are far above the critical point of water. This means that water is unlikely to contribute to the dielectric properties of either planet. The dielectric constant of the surface of the Moon is determined largely by the bulk density and is related to the density by the formula = (1.93 ± 0.17) for dielectric constant, k,at density p g/cm3. Thus, most soils have k about 3, while solid rocks have k about 7.5. Loss tangents appear to be dependent upon density, frequency, temperature, and possibly ilmenite content, and thus are more difficult to predict than the dielectric constant. Typical loss tangents are likely about 0.005 for the Moon, Mars and Mercury, and about 0.01 to 0.2 for Venus.

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Mars: A possible discrepancy between the radio spectrum and elementary theory

Cited by 16 publications

References 34 publications

Mars: Measurements of its brightness temperature at 1.85 and 3.75 cm wavelength

Mars: Measurements of its brightness temperature at 1.85 and 3.75 cm wavelength

An Absolute Flux Density Measurement of the Supernova Remnant Cassiopeia A at 32 GH[CLC]z[/CLC]

Electrical properties of planetary surfaces

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