Mercury: Thermal emission at radio wavelengths

Epstein, E. E.; Andrew, B. H.

doi:10.1016/0019-1035(85)90187-3

Cited by 4 publications

(15 citation statements)

References 11 publications

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“…A few observations close to upper conjunction apparently show a real "anomaly", of up to ∼30% (see Fig. 4, hot region), as also mentioned by Epstein & Andrew (1985).…”

Section: Observationssupporting

confidence: 49%

“…Combining our 3 mm data with those of Epstein & Andrew (1985), and accounting for the phase efffect, we derive at 3 mm the variation of the disk-averaged brightness temperature as a function of Mercury's longitude. From the combination of the mm-observations with published longer wavelength observations we are able to derive the midnight and noon brightness temperature as a function of wavelength.…”

Section: Article Published By Edp Sciencesmentioning

confidence: 99%

“…(which assumes a homogeneous body of Mercury with no longitude and latitude dependence of the surface properties), Epstein & Andrew (1985) binned their 99 observed 3.3 mm brightness temperatures into the hot surface regions (330…”

Section: The 90 Ghz Intervalmentioning

confidence: 99%

“…Mercury has been observed at radio wavelengths down to 3.3 mm during the years ∼1960 to 1985, thereafter the interest in single-dish observations had somewhat faded (Soter & Ulrichs 1967;Morrison 1970;Klein 1970;Morrison & Klein 1970;Epstein et al 1970;Epstein & Andrew 1985). Single-dish observations must extend over long time intervals in order to cover the diurnal thermal behaviour of specific surface areas, while interferometer observations (Ledlow et al 1992;Mitchell & de Pater 1994) provide snapshots of the diurnal cycle with, when specially chosen, the effect of surface areas in sunshine and in shadow.…”

Section: Introductionmentioning

confidence: 99%

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The brightness temperature of Mercury at mm-wavelengths

Greve¹,

Thum²,

Moreno

et al. 2008

A&A

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We present observations of Mercury made with the IRAM 30-m telescope at 3, 2 and 1.3 mm wavelength (90, 150 and 230 GHz) during the years 1985−2005; we derive from these data the disk-averaged brightness temperatures. The observations at 3 mm combined with those by Epstein & Andrew allow a separation of the data into 40• wide longitude intervals and by this an investigation of the diskaveraged brightness temperature with Mercury's longitude. From the new mm-wavelength data, and data taken from the literature, we derive the disk-averaged brightness temperature as a function of wavelength. On Mercury's night side a significant decrease in brightness temperature occurs towards shorter wavelengths. We use the three surface models (A,B,C) discussed by Mitchell & de Pater and calculate for the cool and hot surface region the corrresponding diurnal variation of the disk-averaged brightness temperature at 90 GHz. For the same models we calculate the variation of the disk-averaged brightness temperature with wavelength between 1.3 mm and 37 mm, on Mercury's midnight side and noon side. Although the scatter in the observations is large, there seems to be a marginally better agreement with model B and A.

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“…A few observations close to upper conjunction apparently show a real "anomaly", of up to ∼30% (see Fig. 4, hot region), as also mentioned by Epstein & Andrew (1985).…”

Section: Observationssupporting

confidence: 49%

Section: Article Published By Edp Sciencesmentioning

confidence: 99%

Section: The 90 Ghz Intervalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The brightness temperature of Mercury at mm-wavelengths

Greve¹,

Thum²,

Moreno

et al. 2008

A&A

View full text Add to dashboard Cite

show abstract

“…The disk-averaged brightness temperature of Mercury is more complicated, depending not only on heliocentric distance but also phase angle, since the Sun-facing side of Mercury is significantly warmer than its shadowed hemisphere. Consequently, models for Mercury's brightness temperature variation (Epstein & Andrew 1985) are more poorly constrained and this object is a less reliable calibrator. Therefore, we chose to use our Mars data to determine η mb for the 2003 season, and our Jupiter data to determine η mb for the 2004 season.…”

Section: Beam Efficiencymentioning

confidence: 99%

Beam Size, Shape and Efficiencies for the ATNF Mopra Radio Telescope at 86–115 GHz

Ladd

Purcell

Wong

et al. 2005

Publ. Astron. Soc. Aust

177

211

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Abstract:We present data characterising the performance of the Mopra Radio Telescope during the period 2000-2004, including measurements of the beam size and shape, as well as the overall beam efficiency of the telescope. In 2004 the full width half maximum of the beam was measured to be 36 ± 3 at 86 GHz, falling to 33 ± 2 at 115 GHz. Based on our observations of Jupiter we measured the beam efficiency of the Gaussian main beam to be 0.49 ± 0.03 at 86 GHz and 0.42 ± 0.02 at 115 GHz. Sources with angular sizes of ∼80 couple well to the main beam, while sources with angular sizes between ∼80 and ∼160 couple to the both the main beam and inner error beam. Measurements indicate that the inner error beam contains approximately one-third the power of the main beam. We also compare efficiency corrected spectra to measurements made at similar facilities and present standard spectra taken towards the molecular clouds Orion-KL and M17-SW.

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Mercury: full‐disk radar images and the detection and stability of ice at the North Pole

Butler¹,

Muhleman²,

Slade³

1993

J. Geophys. Res.

197

190

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The first full-disk radar images of Mercury were obtained on August 8 and 23, 1991. These images were constructed using the Very Large Array (VLA) in Socorro, New Mexico, to receive and map radar flux at 3.5 cm (X band) which was continuously transmitted from the 70-m Jet Propulsion Laboratory/Deep Space Network antenna at Goldstone, California. Approximately 77% of the surface was imaged, at resolutions as good as 150 km. About half of the hemisphere photographed by Mariner 10 was imaged, as well as most of the hemisphere which has not previously been photographed. At the time of the observations, the north pole was visible, and the feature with the highest same sense (SS) circular reflectivity in the images is near the nominal polar position. The peak SS reflectivity of this feature was 7.9%, and the circular polarization ratio throughout much of the feature is > 1. Our best estimate of the size of the feature is that its diameter is •<350 km. We interpret the feature to be indicative of the presence of ices because of the signal strength and polarization characteristics. The ices must be very clean and were thus probably deposited in a relatively short time period. The most likely place to find these ices is in any permanently shadowed areas in the polar regions, which would be very cold. In comparison to absolute refiectivities of other icy bodies and regions in the solar system, the reflectivity of the north polar feature is slightly depressed. This is probably because the ices do not fill an observational resolution cell (i.e., there is incomplete areal coverage), or are covered by a layer of dust or soil, which absorbs some of the incoming and outgoing radar energy, or both. A covering layer would also protect any ices from erosion by energetic sources. Other prominent features on the unphotographed hemisphere correspond to positions where atmospheric sodium enhancements have been measured from Earth. This may indicate that these locations are large basins similar to the Caloris basin, where an atmospheric potassium enhancement has been measured, which may be the result of increased degas sing in the disrupted surface and near surface. Direct comparison of the radar echoes from our features with those from the Caloris basin are hard to make, as Caloris was not imaged by us in a favorable geometry. Features on the photographed hemisphere are smaller and mostly associated with craters and crater complexes, most notably the Kuiper crater and its environs. 15,003

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Mercury: Thermal emission at radio wavelengths

Cited by 4 publications

References 11 publications

The brightness temperature of Mercury at mm-wavelengths

The brightness temperature of Mercury at mm-wavelengths

Beam Size, Shape and Efficiencies for the ATNF Mopra Radio Telescope at 86–115 GHz

Mercury: full‐disk radar images and the detection and stability of ice at the North Pole

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