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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Optical Polarimetry of the May 2022 Lunar Eclipse
AU - Steele, Iain
AU - Wiersema, Klaas
AU - McCall, Callum
AU - Newsam, Andrew
AU - Shrestha, Manisha
PY - 2023/1/31
Y1 - 2023/1/31
N2 - The sunlight reflected from the Moon during a total lunar eclipse has been transmitted through the Earth’s atmosphere on the way to the Moon. The combination of multiple scattering and inhomogeneous atmospheric characteristics during that transmission can potentially polarize that light. A similar (although much smaller) effect should also be observable from the atmosphere of a transiting exoplanet. We present the results of polarization observations during the first 15 min of totality of the lunar eclipse of 2022 May 16. We find degrees of polarization of 2.1 ± 0.4 per cent in B, 1.2 ± 0.3 per cent in V, 0.5 ± 0.2 per cent in R, and 0.2 ± 0.2 per cent in I. Our polarization values lie in the middle of the range of those reported for previous eclipses, providing further evidence that the induced polarization can change from event to event. We found no significant polarization difference (<0.02 per cent) between a region of dark Mare and nearby bright uplands or between the lunar limb and regions closer to the disc centre due to the different angle of incidence. This further strengthens the interpretation of the polarization’s origin being due to scattering in the Earth’s atmosphere rather than by the lunar regolith.
AB - The sunlight reflected from the Moon during a total lunar eclipse has been transmitted through the Earth’s atmosphere on the way to the Moon. The combination of multiple scattering and inhomogeneous atmospheric characteristics during that transmission can potentially polarize that light. A similar (although much smaller) effect should also be observable from the atmosphere of a transiting exoplanet. We present the results of polarization observations during the first 15 min of totality of the lunar eclipse of 2022 May 16. We find degrees of polarization of 2.1 ± 0.4 per cent in B, 1.2 ± 0.3 per cent in V, 0.5 ± 0.2 per cent in R, and 0.2 ± 0.2 per cent in I. Our polarization values lie in the middle of the range of those reported for previous eclipses, providing further evidence that the induced polarization can change from event to event. We found no significant polarization difference (<0.02 per cent) between a region of dark Mare and nearby bright uplands or between the lunar limb and regions closer to the disc centre due to the different angle of incidence. This further strengthens the interpretation of the polarization’s origin being due to scattering in the Earth’s atmosphere rather than by the lunar regolith.
U2 - 10.1093/mnras/stac2816
DO - 10.1093/mnras/stac2816
M3 - Journal article
VL - 518
SP - 1214
EP - 1221
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 1
ER -