J/A+A/635/A156 Total lunar eclipse January 2019 spectra (Strassmeier+, 2020)
High-resolution spectroscopy and spectropolarimetry of the total lunar eclipse
January 2019.
Strassmeier K.G., Ilyin I., Keles E., Mallonn M., Jaervinen A., Weber M.,
Mackebrandt F., Hill J.M.
<Astron. Astrophys. 635, A156 (2020)>
=2020A&A...635A.156S 2020A&A...635A.156S (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Sun ; Spectroscopy
Keywords: solar-terrestrial relations - Sun: atmosphere - Earth - Moon -
eclipses - polarization
Abstract:
Observations of the Earthshine o 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.
We thus aim at transmission spectroscopy of an Earth transit by
tracing the solar spectrum during the total lunar eclipse of January
21, 2019.
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 130000 (0.06Å). In particular, the spectra
cover the red parts of the optical spectrum between 7419-9067Å. The
spectrograph's exposure meter was used to obtain a light curve of the
lunar eclipse.
The brightness of the Moon dimmed by 10.75m during umbral eclipse. We
found both branches of the O2 A-band almost completely saturated as
well as a strong increase of H2O absorption during totality. A
pseudo O2 emission feature remained at a wavelength of 7618Å, 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 NaI 5890Å
doublet, the CaII infrared triplet around 8600Å, and the KI line at
7699Å in addition to several hyper-fine-structure lines of MnI and
even from BaII. The detections of the latter two elements are likely
due to an untypical solar center-to-limb eect rather than Earth's
atmosphere. The absorption in CaII and KI remained visible throughout
umbral eclipse. Our radial velocities trace a wavelength dependent
Rossiter-McLaughlin eect of the Earth eclipsing the Sun as seen from
the Tycho crater and thereby confirm earlier observations. A small
continuum polarization of the O2 A-band of 0.12% during umbral
eclipse was detected at 6.3. No line polarization of the O2 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.
Description:
All observations were obtained with PEPSI (Strassmeier et al.,
2015AN....336..324S 2015AN....336..324S) at the 28.4m LBT (Hill et al., 2012, Proc. SPIE,
8444-1) in Arizona.
Observations of the Moon commenced between UT 3:25 and 7:41 on January
21, 2019. Maximum of the total eclipse was at UT 5:12.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 124 127 List of spectra
fits/* . 127 Individual spectra
s1s.tab 2880 17 Fits table with informations
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Description of file:
fits/* :
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Col Unit Label Explanations
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1 Angstroms Arg Wavelength in the laboratory wavelength scale
2 Intensity Fun Continuum normalized intensity
3 Variance Var Variance for each wavelength pixel
4 Byte Mask A mask column for data processing
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Nx Number of pixels along X-axis
4- 9 I6 --- Ny Number of pixels along Y-axis
11- 31 A21 "datime" Obs.date Observation date
33- 36 I4 Kibyte size Size of FITS file
38- 68 A31 --- FileName Name of FITS file, in subdirectory fits
70-124 A55 --- Title Title of the FITS file
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Acknowledgements:
Ilya Ilyin, ilyin(at)aip.de
(End) Patricia Vannier [CDS] 24-Feb-2020