Earthshine observation of vegetation and implication for life detection on other planets - A review of 2001 - 2006 works
Invited talk in "Strategies for Life Detection" (ISSI Bern, 24-28 April 2006) to appear in a hardcopy volume of the ISSI Space Science Series, Eds, J. Bada et al., and also in an issue of Space Science Reviews. 13 pages, 8 figures, 1 table. V2 and V3: a few typos corrected. The detection o...
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ftunivaixmarseil:oai:HAL:hal-00157499v3 2023-12-17T10:51:14+01:00 Earthshine observation of vegetation and implication for life detection on other planets - A review of 2001 - 2006 works Arnold, Luc Observatoire de Haute-Provence (OHP) Institut Pythéas (OSU PYTHEAS) Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS) 2007-06-26 https://hal.science/hal-00157499 https://hal.science/hal-00157499v3/document https://hal.science/hal-00157499v3/file/arnold_issi2006_revised.pdf en eng HAL CCSD info:eu-repo/semantics/altIdentifier/arxiv/0706.3798 hal-00157499 https://hal.science/hal-00157499 https://hal.science/hal-00157499v3/document https://hal.science/hal-00157499v3/file/arnold_issi2006_revised.pdf ARXIV: 0706.3798 info:eu-repo/semantics/OpenAccess https://hal.science/hal-00157499 2007 vegetation red edge global biomarker biosignature extrasolar planet Earthshine Earth's spectrum [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] info:eu-repo/semantics/preprint Preprints, Working Papers, . 2007 ftunivaixmarseil 2023-11-21T23:50:31Z Invited talk in "Strategies for Life Detection" (ISSI Bern, 24-28 April 2006) to appear in a hardcopy volume of the ISSI Space Science Series, Eds, J. Bada et al., and also in an issue of Space Science Reviews. 13 pages, 8 figures, 1 table. V2 and V3: a few typos corrected. The detection of exolife is one of the goals of very ambitious future space missions that aim to take direct images of Earth-like planets. While associations of simple molecules present in the planet's atmosphere ($O_2$, $O_3$, $CO_2$ etc.) have been identified as possible global biomarkers, we review here the detectability of a signature of life from the planet's surface, i.e. the green vegetation. The vegetation reflectance has indeed a specific spectrum, with a sharp edge around 700 nm, known as the "Vegetation Red Edge" (VRE). Moreover vegetation covers a large surface of emerged lands, from tropical evergreen forest to shrub tundra. Thus considering it as a potential global biomarker is relevant. Earthshine allows to observe the Earth as a distant planet, i.e. without spatial resolution. Since 2001, Earthshine observations have been used by several authors to test and quantify the detectability of the VRE in the Earth spectrum. The vegetation spectral signature is detected as a small 'positive shift' of a few percents above the continuum, starting at 700 nm. This signature appears in most spectra, and its strength is correlated with the Earth's phase (visible land versus visible ocean). The observations show that detecting the VRE on Earth requires a photometric relative accuracy of 1\% or better. Detecting something equivalent on an Earth-like planet will therefore remain challenging, moreover considering the possibility of mineral artifacts and the question of 'red edge' universality in the Universe. Report Tundra Aix-Marseille Université: HAL |
institution |
Open Polar |
collection |
Aix-Marseille Université: HAL |
op_collection_id |
ftunivaixmarseil |
language |
English |
topic |
vegetation red edge global biomarker biosignature extrasolar planet Earthshine Earth's spectrum [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] |
spellingShingle |
vegetation red edge global biomarker biosignature extrasolar planet Earthshine Earth's spectrum [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] Arnold, Luc Earthshine observation of vegetation and implication for life detection on other planets - A review of 2001 - 2006 works |
topic_facet |
vegetation red edge global biomarker biosignature extrasolar planet Earthshine Earth's spectrum [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] |
description |
Invited talk in "Strategies for Life Detection" (ISSI Bern, 24-28 April 2006) to appear in a hardcopy volume of the ISSI Space Science Series, Eds, J. Bada et al., and also in an issue of Space Science Reviews. 13 pages, 8 figures, 1 table. V2 and V3: a few typos corrected. The detection of exolife is one of the goals of very ambitious future space missions that aim to take direct images of Earth-like planets. While associations of simple molecules present in the planet's atmosphere ($O_2$, $O_3$, $CO_2$ etc.) have been identified as possible global biomarkers, we review here the detectability of a signature of life from the planet's surface, i.e. the green vegetation. The vegetation reflectance has indeed a specific spectrum, with a sharp edge around 700 nm, known as the "Vegetation Red Edge" (VRE). Moreover vegetation covers a large surface of emerged lands, from tropical evergreen forest to shrub tundra. Thus considering it as a potential global biomarker is relevant. Earthshine allows to observe the Earth as a distant planet, i.e. without spatial resolution. Since 2001, Earthshine observations have been used by several authors to test and quantify the detectability of the VRE in the Earth spectrum. The vegetation spectral signature is detected as a small 'positive shift' of a few percents above the continuum, starting at 700 nm. This signature appears in most spectra, and its strength is correlated with the Earth's phase (visible land versus visible ocean). The observations show that detecting the VRE on Earth requires a photometric relative accuracy of 1\% or better. Detecting something equivalent on an Earth-like planet will therefore remain challenging, moreover considering the possibility of mineral artifacts and the question of 'red edge' universality in the Universe. |
author2 |
Observatoire de Haute-Provence (OHP) Institut Pythéas (OSU PYTHEAS) Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS) |
format |
Report |
author |
Arnold, Luc |
author_facet |
Arnold, Luc |
author_sort |
Arnold, Luc |
title |
Earthshine observation of vegetation and implication for life detection on other planets - A review of 2001 - 2006 works |
title_short |
Earthshine observation of vegetation and implication for life detection on other planets - A review of 2001 - 2006 works |
title_full |
Earthshine observation of vegetation and implication for life detection on other planets - A review of 2001 - 2006 works |
title_fullStr |
Earthshine observation of vegetation and implication for life detection on other planets - A review of 2001 - 2006 works |
title_full_unstemmed |
Earthshine observation of vegetation and implication for life detection on other planets - A review of 2001 - 2006 works |
title_sort |
earthshine observation of vegetation and implication for life detection on other planets - a review of 2001 - 2006 works |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.science/hal-00157499 https://hal.science/hal-00157499v3/document https://hal.science/hal-00157499v3/file/arnold_issi2006_revised.pdf |
genre |
Tundra |
genre_facet |
Tundra |
op_source |
https://hal.science/hal-00157499 2007 |
op_relation |
info:eu-repo/semantics/altIdentifier/arxiv/0706.3798 hal-00157499 https://hal.science/hal-00157499 https://hal.science/hal-00157499v3/document https://hal.science/hal-00157499v3/file/arnold_issi2006_revised.pdf ARXIV: 0706.3798 |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1785576428764397568 |