Radio Observations of the Crab Nebula during a Lunar Occultation

Andrew, B. H.; Branson, N. J. B. A.; Wills, D.

doi:10.1038/203171b0

Cited by 30 publications

(14 citation statements)

References 4 publications

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“…In contrast to these studies are several radio occultation experiments performed with radio stars, in which the radio sources showed large angular shifts when they were occulted by the dayside lunar limb (Elsmore 1957; Andrew et al 1964). These angular shifts can be explained by the refraction of radio waves in the lunar ionosphere, provided that the ionosphere has electron densities of ∼1000 cm −3 and a thickness of several tens of kilometers (Vyshlov and Savich 1979).…”

Section: Introductionmentioning

confidence: 93%

Studying the Lunar Ionosphere with SELENE Radio Science Experiment

et al. 2010

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Radio occultation observations of the electron density near the lunar surface were conducted during the SELENE (Kaguya) mission using the Vstar and Rstar sub-satellites. Previous radio occultation measurements conducted in the Soviet lunar missions have indicated the existence of an ionosphere with peak densities of several hundreds of electrons per cubic centimeters above the dayside lunar surface. These densities are difficult to explain theoretically when the removal of plasma by the solar wind is considered, and thus the generation mechanism of the lunar ionosphere is a major issue, with even the validity of previous observations still under debate. The most serious error source in the measurement T. Imamura ( ) · T. Iwata · Z.-i. Yamamoto · N. Mochizuki

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Section: Introductionmentioning

confidence: 93%

Studying the Lunar Ionosphere with SELENE Radio Science Experiment

et al. 2010

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“…Large angular shifts in radio waves were routinely observed when stellar radio signals were occulted by the dayside lunar limb [Elsmore, 1957;Andrew et al, 1964] and were ascribed to the existence of lunar ionosphere with electron density of the order of 1000 cm −3 and thickness of several kilometers. The electron density near the Moon's surface, obtained on 31 July 2009 (∼300 cm −3 ), is compared with results from a model which includes production and recombination of 16 ions, solar wind proton charge exchange, and the electron impact ionization.…”

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confidence: 99%

“…Large angular shifts in radio waves were routinely observed when stellar radio signals were occulted by the dayside lunar limb [Elsmore, 1957;Andrew et al, 1964] and were ascribed to the existence of lunar ionosphere with electron density of the order of 1000 cm −3 and thickness of several kilometers. Large angular shifts in radio waves were routinely observed when stellar radio signals were occulted by the dayside lunar limb [Elsmore, 1957;Andrew et al, 1964] and were ascribed to the existence of lunar ionosphere with electron density of the order of 1000 cm −3 and thickness of several kilometers.…”

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confidence: 99%

On the origin of the ionosphere at the Moon using results from Chandrayaan‐1 S band radio occultation experiment and a photochemical model

Choudhary

Ambili

Choudhury

et al. 2016

Geophysical Research Letters

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The origin of the Moon's ionosphere has been explored using Chandrayaan‐1 radio occultation (RO) measurements and a photochemical model. The electron density near the Moon's surface, obtained on 31 July 2009 (∼300 cm−3), is compared with results from a model which includes production and recombination of 16 ions, solar wind proton charge exchange, and the electron impact ionization. The model calculations suggest that in the absence of transport, inert ions, namely Ar+, Ne+, and He+, dominate lunar ionosphere (density ∼5 × 104 cm−3). Interaction with solar wind, however, leads to their complete removal (∼2–3 cm−3). Assuming the Moon's exosphere to have CO2, H2O, O, OH, H2, CH4, and CO molecules in addition to the inert gases, the model calculations suggest that the lunar ionosphere is dominated by molecular ions, namely H2O+, CO 2+, and H3O+, with near‐surface density ∼250 cm−3. We surmise that lunar ionosphere can be molecular in nature.

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“…occulted by the dayside lunar limb (e.g., Elsmore, 1957;Andrew et al, 1964). These angular shifts can be explained by the refraction of radio waves in the lunar ionosphere, provided that the ionosphere has electron densities of ∼1000 cm −3 and a thickness of several tens of kilometers (Vyshlov and Savich, 1979).…”

Section: Introductionmentioning

confidence: 99%

The possibility of studying the lunar ionosphere with the SELENE radio science experiment

et al. 2008

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The electron density profiles above the lunar surface will be observed by the radio occultation technique during the SELENE mission using the Vstar sub-satellite. Previous radio occultation observations have indicated the existence of an ionosphere with densities of up to 1000 cm −3 above the dayside lunar surface. The measured densities are difficult to explain theoretically when the removal of plasma by the solar wind is considered, and thus the generation mechanism of the lunar ionosphere is a major issue, with even the validity of previous observations still under debate. The SELENE radio science experiment will establish the morphology of the lunar ionosphere and will reveal its relationship with various physical conditions to provide possible clues to the mechanism.

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Radio Observations of the Crab Nebula during a Lunar Occultation

Cited by 30 publications

References 4 publications

Studying the Lunar Ionosphere with SELENE Radio Science Experiment

Studying the Lunar Ionosphere with SELENE Radio Science Experiment

On the origin of the ionosphere at the Moon using results from Chandrayaan‐1 S band radio occultation experiment and a photochemical model

The possibility of studying the lunar ionosphere with the SELENE radio science experiment

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