%0 Generic %1 youngblood2020hubble %A Youngblood, Allison %A Arney, Giada N. %A Muñoz, Antonio García %A Stocke, John T. %A France, Kevin %A Roberge, Aki %D 2020 %K science %R 10.3847/1538-3881/aba0b4 %T The Hubble Space Telescope's near-UV and optical transmission spectrum of Earth as an exoplanet %U http://arxiv.org/abs/2008.01837 %X We observed the 2019 January total lunar eclipse with the Hubble Space Telescope's STIS spectrograph to obtain the first near-UV (1700-3200 $A$) observation of Earth as a transiting exoplanet. The observatories and instruments that will be able to perform transmission spectroscopy of exo-Earths are beginning to be planned, and characterizing the transmission spectrum of Earth is vital to ensuring that key spectral features (e.g., ozone, or O$_3$) are appropriately captured in mission concept studies. O$_3$ is photochemically produced from O$_2$, a product of the dominant metabolism on Earth today, and it will be sought in future observations as critical evidence for life on exoplanets. Ground-based observations of lunar eclipses have provided the Earth's transmission spectrum at optical and near-IR wavelengths, but the strongest O$_3$ signatures are in the near-UV. We describe the observations and methods used to extract a transmission spectrum from Hubble lunar eclipse spectra, and identify spectral features of O$_3$ and Rayleigh scattering in the 3000-5500 A region in Earth's transmission spectrum by comparing to Earth models that include refraction effects in the terrestrial atmosphere during a lunar eclipse. Our near-UV spectra are featureless, a consequence of missing the narrow time span during the eclipse when near-UV sunlight is not completely attenuated through Earth's atmosphere due to extremely strong O$_3$ absorption and when sunlight is transmitted to the lunar surface at altitudes where it passes through the O$_3$ layer rather than above it.

@misc{youngblood2020hubble, abstract = {We observed the 2019 January total lunar eclipse with the Hubble Space Telescope's STIS spectrograph to obtain the first near-UV (1700-3200 $\r{A}$) observation of Earth as a transiting exoplanet. The observatories and instruments that will be able to perform transmission spectroscopy of exo-Earths are beginning to be planned, and characterizing the transmission spectrum of Earth is vital to ensuring that key spectral features (e.g., ozone, or O$_3$) are appropriately captured in mission concept studies. O$_3$ is photochemically produced from O$_2$, a product of the dominant metabolism on Earth today, and it will be sought in future observations as critical evidence for life on exoplanets. Ground-based observations of lunar eclipses have provided the Earth's transmission spectrum at optical and near-IR wavelengths, but the strongest O$_3$ signatures are in the near-UV. We describe the observations and methods used to extract a transmission spectrum from Hubble lunar eclipse spectra, and identify spectral features of O$_3$ and Rayleigh scattering in the 3000-5500 \r{A} region in Earth's transmission spectrum by comparing to Earth models that include refraction effects in the terrestrial atmosphere during a lunar eclipse. Our near-UV spectra are featureless, a consequence of missing the narrow time span during the eclipse when near-UV sunlight is not completely attenuated through Earth's atmosphere due to extremely strong O$_3$ absorption and when sunlight is transmitted to the lunar surface at altitudes where it passes through the O$_3$ layer rather than above it.}, added-at = {2020-08-06T09:52:08.000+0200}, author = {Youngblood, Allison and Arney, Giada N. and Muñoz, Antonio García and Stocke, John T. and France, Kevin and Roberge, Aki}, biburl = {https://www.bibsonomy.org/bibtex/2b0c9b65e70e15330dcb5cd3df1a86812/d31fva}, description = {The Hubble Space Telescope's near-UV and optical transmission spectrum of Earth as an exoplanet}, doi = {10.3847/1538-3881/aba0b4}, interhash = {118dec19148bdbd08070d973a479cb91}, intrahash = {b0c9b65e70e15330dcb5cd3df1a86812}, keywords = {science}, note = {cite arxiv:2008.01837Comment: 27 pages, 14 figures, 1 table, published in the Astronomical Journal}, timestamp = {2020-08-06T09:52:08.000+0200}, title = {The Hubble Space Telescope's near-UV and optical transmission spectrum of Earth as an exoplanet}, url = {http://arxiv.org/abs/2008.01837}, year = 2020 }