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Floyd, L.; Reiser, P. A.; Crane, P. C.; Herring, L. C.; Prinz, D. K.; Brueckner, G. E.

doi:10.1023/a:1004907902440

Cited by 51 publications

(14 citation statements)

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“…Solar data are from the SUSIM instrument (Floyd et al 1998). The dependence of absorption and photodissociation crosssections and branching ratios with temperature are now included when they are known.…”

Section: The Photochemical Model Phoebementioning

confidence: 99%

Signature of life on exoplanets: Can Darwin produce false positive detections?

Selsis

Despois

Parisot

2002

A&A

178

209

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Abstract. Darwin (ESA) and Terrestrial Planet Finder-TPF (NASA) are two projects of space telescopes aiming at the detection of extra-solar terrestrial planets and some of their atmospheric components. In particular, they will be sensitive to the 9.6 µm band of O3 which may be the signature of an O2-rich atmosphere produced by photosynthetic life forms. In this paper, we point out that O2, and hence O3, can also be produced by photochemistry and we investigate the risk of "false positive" detection of life incurred by these missions. For this purpose, we have developed new photochemical and radiative-convective models of terrestrial planet atmospheres. By modelling the photochemistry of some realistic atmospheres, (including present and past Earth and Mars) we show that O2-rich atmospheres (up to 5%) and IR absorbing O3 layers can build up without life from H2O and CO2 photolysis. However, Darwin can still provide a reliable way to detect, through their mid-infrared signatures, ecosystems which have developed oxygenic photosynthesis. Indeed, the two photochemical sources of O2 are shown to interfere with each other; second, when the CO2 pressure is high enough (>50 mbar) to produce appreciable amounts of O2 and O3, it also masks the O3 feature; and third, the by-products of H2O photolysis destroy O3. As a result, whereas the unique detection of O2 remains ambiguous, the simultaneous infrared detection of O3, CO2 and H2O, provided by Darwin, is established to be a robust way to discriminate photochemical O2 production from biological photosynthesis: none of the atmospheres modelled exhibits this "triple signature", even in the most extreme "high risk" cases.

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Section: The Photochemical Model Phoebementioning

confidence: 99%

Signature of life on exoplanets: Can Darwin produce false positive detections?

Selsis

Despois

Parisot

2002

A&A

178

209

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“…The large rotational modulation of solar irradiances at ultraviolet wavelengths (Lean 1987;Lean et al 1992;Floyd et al 1998b) is the consequence of the enhanced surface brightness of solar active region plage compared to the quiet disk of the Sun. The degree of that enhancement is the solar contrast and often is defined in terms of the excess surface brightness (Chapman & McGuire 1977):…”

Section: Introductionmentioning

confidence: 99%

The center-to-limb behavior of solar active regions at ultraviolet wavelengths

Crane

Floyd²,

Cook

et al. 2004

A&A

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et al. ( , ApJ, 560, 1020) are found to be complementary and could be productively combined in future work. We also compare our results with a similar analysis based upon the semi-empirical model atmospheres of Fontenla et al. (1999, ApJ, 518, 480), further improved by Avrett. We compare the measurement-and model-based analyses and suggest the direction of improvements needed in the model atmospheres.

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“…The illumination of the diffuser by the HC lamp is performed using a fused-silica condenser and an optical fibre. In addition, the two deuterium lamps (Key & Preston 1980) were used as relative spectral irradiance standards to calibrate the radiometric response Floyd et al 1996). These lamps were originally designed for the SUSIM experiment by Cathodeon Ltd, UK, but instead a new batch of lamps was produced and delivered for SOLAR/SOLSPEC.…”

Section: Instrument Descriptionmentioning

confidence: 99%

“…The operating principle was to have one lamp that would be used monthly during the mission, while the second lamp was to be used after each solar spectrum measurement. We used an algorithm developed for the SUSIM experiment, described in detail by Floyd et al (1996) and Prinz et al (1996), and adapted for SOLSPEC by Bolsée (2012). The principle is that for lamps proven to have the same aging rate (such lamps were selected during flight model selection in the laboratory), the algorithm is used to monitor and correct the differential aging of the lamps themselves.…”

Section: Correction Of the Responsivity Degradation During The Solar mentioning

confidence: 99%

SOLAR/SOLSPEC mission on ISS: In-flight performance for SSI measurements in the UV

Bolsée

Pereira

Gillotay

et al. 2017

A&A

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Context. The SOLar SPECtrum (SOLSPEC) experiment is part of the Solar Monitoring Observatory (SOLAR) payload, and has been externally mounted on the Columbus module of the International Space Station (ISS) since 2008. SOLAR/SOLSPEC combines three absolutely calibrated double monochromators with concave gratings for measuring the solar spectral irradiance (SSI) from 166 nm to 3088 nm. This physical quantity is a key input for studies of climatology, planetary atmospheres, and solar physics. Aims. A general description of the instrument is given, including in-flight operations and performance of the ultraviolet (UV) channel from 175 nm to 340 nm. Methods. We developed a range of processing and correction methods, which are described in detail. For example, methods for correcting thermal behavior effects, instrument linearity, and especially the accuracy of the wavelength and absolute radiometric scales have been validated by modeling the standard uncertainties. Results. The deliverable is a quiet Sun UV reference solar spectrum as measured by SOLAR/SOLSPEC during the minimum of solar activity prior to cycle 24. Comparisons with other instruments measuring SSI are also presented.

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Cited by 51 publications

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Signature of life on exoplanets: Can Darwin produce false positive detections?

Signature of life on exoplanets: Can Darwin produce false positive detections?

The center-to-limb behavior of solar active regions at ultraviolet wavelengths

SOLAR/SOLSPEC mission on ISS: In-flight performance for SSI measurements in the UV

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