Polarized Transmission Spectrum of Earth as Observed during a Lunar Eclipse

Takahashi, Jun; Itoh, Yoichi; Hosoya, Kensuke; Yanamandra-Fisher, P. A.; Hattori, Takashi

doi:10.3847/1538-3881/aa91d6

Cited by 3 publications

(12 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This line polarization is not to be confused with the 2% disk-integrated continuum polarization first seen by Coyne & Pellicori (1970) which is explained by double scattering in the Earth's atmosphere. We extracted continuum polarization from our Foster beam splitter alone, that is without a λ/2 retarder, and obtained a 6.3σ 0.12% degree of continuum polarization in the O 2 A-band during umbral eclipse, significantly weaker than the 1-3 % seen by Takahashi et al (2017) for the lunar eclipse in 2014. We consider our continuum polarization very uncertain though.…”

Section: Discussionmentioning

confidence: 99%

“…Previous low resolution observations used a long-slit or a multi-slit set-up in which one end of the slit, or one of the slits, was positioned just outside the Moon and thus record sky, which then can be used for telluric subtraction. Several authors proceeded in this way for intensity and polarimetric observations (e.g., Pallé et al 2009, Sterzik et al 2012, Takahashi et al 2017. High-resolution fiber-fed spectrographs usually can not do this because their fibers are too close together on the sky, in particular PEPSI cannot do this if used in spectro-polarimetric mode.…”

Section: Instrumental Set Upmentioning

confidence: 99%

Section: Instrumental Set Upmentioning

confidence: 99%

“…After this first detection of polarization during lunar eclipses it took nearly 50 years until Coyne & Pellicori's results were confirmed with modern observations. Takahashi et al (2017) used the 8.2 m Subaru telescope to monitor the total lunar eclipse from April 4, 2015. They observed polarization degrees of 2-3 % at wavelengths of 500−600 nm and, in addition, an enhanced feature at the O 2 Aband near 760 nm consistent with the explanation of polarization caused by double scattering during the first transmission through Earth's atmosphere.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

High-resolution spectroscopy and spectropolarimetry of the total lunar eclipse January 2019

Strassmeier

Ilyin

Keles

et al. 2020

A&A

View full text Add to dashboard Cite

Context. Observations of the Earthshine off the Moon allow for the unique opportunity to measure the large-scale Earth atmosphere. Another opportunity is realized during a total lunar eclipse which, if seen from the Moon, is like a transit of the Earth in front of the Sun. Aims. We thus aim at transmission spectroscopy of an Earth transit by tracing the solar spectrum during the total lunar eclipse of January 21, 2019. Methods. Time series spectra of the Tycho crater were taken with the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in its polarimetric mode in Stokes IQUV at a spectral resolution of 130 000 (0.06 Å). In particular, the spectra cover the red parts of the optical spectrum between 7419-9067 Å. The spectrograph's exposure meter was used to obtain a light curve of the lunar eclipse.Results. The brightness of the Moon dimmed by 10. m 75 during umbral eclipse. We found both branches of the O 2 A-band almost completely saturated as well as a strong increase of H 2 O absorption during totality. A pseudo O 2 emission feature remained at a wavelength of 7618 Å, but it is actually only a residual from different P-branch and R-branch absorptions. It nevertheless traces the eclipse. The deep penumbral spectra show significant excess absorption from the Na i 5890-Å doublet, the Ca ii infrared triplet around 8600 Å, and the K i line at 7699 Å in addition to several hyper-fine-structure lines of Mn i and even from Ba ii. The detections of the latter two elements are likely due to an untypical solar center-to-limb effect rather than Earth's atmosphere. The absorption in Ca ii and K i remained visible throughout umbral eclipse. Our radial velocities trace a wavelength dependent Rossiter-McLaughlin effect of the Earth eclipsing the Sun as seen from the Tycho crater and thereby confirm earlier observations. A small continuum polarization of the O 2 A-band of 0.12 % during umbral eclipse was detected at 6.3σ. No line polarization of the O 2 A-band, or any other spectral-line feature, is detected outside nor inside eclipse. It places an upper limit of ≈0.2% on the degree of line polarization during transmission through Earth's atmosphere and magnetosphere.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Instrumental Set Upmentioning

confidence: 99%

Section: Instrumental Set Upmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

High-resolution spectroscopy and spectropolarimetry of the total lunar eclipse January 2019

Strassmeier

Ilyin

Keles

et al. 2020

A&A

View full text Add to dashboard Cite

show abstract

“…The polarization of the reflected light from the Moon during a total lunar eclipse can act as a probe of the effect of the Earth's atmosphere on the transmission of light from the Sun. Takahashi et al (2017) show that a double scattering in the Earths atmosphere combined with some form of large scale atmospheric inhomogeneity (for example due to latitudinal temperature variability) can in theory produce linear polarization 1 fractions of a few percent. Since the situation in a lunar eclipse is analogous to an exoplanet transit in front of its host star, we might also expect a polarization signal associated with the exoplanet atmosphere.…”

Section: Introductionmentioning

confidence: 97%

Optical polarimetry of the May 2022 lunar eclipse

Steele

Wiersema

McCall

et al. 2022

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

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 minutes 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 percent) between a region of dark Mare and nearby bright uplands or between the lunar limb and regions closer to the disk 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.

show abstract

Comparison of polarization at two lunar eclipse events

Takahashi

Itoh

Watanabe

et al. 2019

Publications of the Astronomical Society of Japan

View full text Add to dashboard Cite

We present the results of imaging polarimetry of the eclipsed Moon on 2014 October 8. The observed polarization degree was less than 1% in both the V and R bands, which contrasts with the reported 2%–3% polarization during the eclipse of 2015 April 4. We examined the Earth’s atmospheric data on the two dates and found that the high (≥7 km) cloud distribution was more inhomogeneous for the 2015 eclipse than it was for the 2014 eclipse. The polarization position angle observed during the 2015 eclipse can be explained if the major polarizing source was high clouds with an intermediate horizontal optical thickness. We suggest a possible dependence of the lunar eclipse polarization on the Earth’s high cloud distribution.

show abstract

Polarized Transmission Spectrum of Earth as Observed during a Lunar Eclipse

Cited by 3 publications

References 27 publications

High-resolution spectroscopy and spectropolarimetry of the total lunar eclipse January 2019

High-resolution spectroscopy and spectropolarimetry of the total lunar eclipse January 2019

Optical polarimetry of the May 2022 lunar eclipse

Comparison of polarization at two lunar eclipse events

Contact Info

Product

Resources

About