Publications by Neil Bowles


The EChO science case

EXPERIMENTAL ASTRONOMY 40 (2015) 329-391

G Tinetti, P Drossart, P Eccleston, P Hartogh, K Isaak, M Linder, C Lovis, G Micela, M Ollivier, L Puig, I Ribas, I Snellen, B Swinyard, F Allard, J Barstow, J Cho, A Coustenis, C Cockell, A Correia, L Decin, R de Kok, P Deroo, T Encrenaz, F Forget, A Glasse, C Griffith, T Guillot, T Koskinen, H Lammer, J Leconte, P Maxted, I Mueller-Wodarg, R Nelson, C North, E Palle, I Pagano, G Piccioni, D Pinfield, F Selsis, A Sozzetti, L Stixrude, J Tennyson, D Turrini, M Zapatero-Osorio, J-P Beaulieu, D Grodent, M Guedel, D Luz, HU Norgaard-Nielsen, T Ray, H Rickman, A Selig, M Swain, M Banaszkiewicz, M Barlow, N Bowles, G Branduardi-Raymont, VC du Foresto, J-C Gerard, L Gizon, A Hornstrup, C Jarchow, F Kerschbaum, G Kovacs, P-O Lagage, T Lim, M Lopez-Morales, G Malaguti, E Pace, E Pascale, B Vandenbussche, G Wright, G Ramos Zapata, A Adriani, R Azzollini, A Balado, I Bryson, R Burston, J Colome, M Crook, A Di Giorgio, M Griffin, R Hoogeveen, R Ottensamer, R Irshad, K Middleton, G Morgante, F Pinsard, M Rataj, J-M Reess, G Savini, J-R Schrader, R Stamper, B Winter, L Abe, M Abreu, N Achilleos, P Ade, V Adybekian, L Affer, C Agnor, M Agundez, C Alard, J Alcala, C Allende Prieto, FJ Alonso Floriano, F Altieri, CA Alvarez Iglesias, P Amado, A Andersen, A Aylward, C Baffa, G Bakos, P Ballerini, M Banaszkiewicz, RJ Barber, D Barrado, EJ Barton, V Batista, G Bellucci, JA Belmonte Aviles, D Berry, B Bezard, D Biondi, M Blecka, I Boisse, B Bonfond, P Borde, P Boerner, H Bouy, L Brown, L Buchhave, J Budaj, A Bulgarelli, M Burleigh, A Cabral, MT Capria, A Cassan, C Cavarroc, C Cecchi-Pestellini, R Cerulli, J Chadney, S Chamberlain, S Charnoz, NC Jessen, A Ciaravella, A Claret, R Claudi, A Coates, R Cole, A Collura, D Cordier, E Covino, C Danielski, M Damasso, HJ Deeg, E Delgado-Mena, C Del Vecchio, O Demangeon, A De Sio, J De Wit, M Dobrijevic, P Doel, C Dominic, E Dorfi, S Eales, C Eiroa, M Espinoza Contreras, M Esposito, V Eymet, N Fabrizio, M Fernandez, B Femena Castella, P Figueira, G Filacchione, L Fletcher, M Focardi, S Fossey, P Fouque, J Frith, M Galand, L Gambicorti, P Gaulme, RJ Garcia Lopez, A Garcia-Piquer, W Gear, J-C Gerard, L Gesa, E Giani, F Gianotti, M Gillon, E Giro, M Giuranna, H Gomez, I Gomez-Leal, J Gonzalez Hernandez, B Gonzalez Merino, R Graczyk, D Grassi, J Guardia, P Guio, J Gustin, P Hargrave, J Haigh, E Hebrard, U Heiter, RL Heredero, E Herrero, F Hersant, D Heyrovsky, M Hollis, B Hubert, R Hueso, G Israelian, N Iro, P Irwin, S Jacquemoud, G Jones, H Jones, K Justtanont, T Kehoe, F Kerschbaum, E Kerins, P Kervella, D Kipping, T Koskinen, N Krupp, O Lahav, B Laken, N Lanza, E Lellouch, G Leto, J Licandro Goldaracena, C Lithgow-Bertelloni, SJ Liu, U Lo Cicero, N Lodieu, P Lognonne, M Lopez-Puertas, MA Lopez-Valverde, IL Rasmussen, A Luntzer, P Machado, C MacTavish, A Maggio, J-P Maillard, W Magnes, J Maldonado, U Mall, J-B Marquette, P Mauskopf, F Massi, A-S Maurin, A Medvedev, C Michaut, P Miles-Paez, M Montalto, P Montanes Rodriguez, M Monteiro, D Montes, H Morais, JC Morales, M Morales-Calderon, G Morello, A Moro Martin, J Moses, A Moya Bedon, F Murgas Alcaino, E Oliva, G Orton, F Palla, M Pancrazzi, E Pantin, V Parmentier, H Parviainen, KY Pena Ramirez, J Peralta, S Perez-Hoyos, R Petrov, S Pezzuto, R Pietrzak, E Pilat-Lohinger, N Piskunov, R Prinja, L Prisinzano, I Polichtchouk, E Poretti, A Radioti, AA Ramos, T Rank-Lueftinger, P Read, K Readorn, R Rebolo Lopez, J Rebordao, M Rengel, L Rezac, M Rocchetto, F Rodler, VJ Sanchez Bejar, AS Lavega, E Sanroma, N Santos, J Sanz Forcada, G Scandariato, F-X Schmider, A Scholz, S Scuderi, J Sethenadh, S Shore, A Showman, B Sicardy, P Sitek, A Smith, L Soret, S Sousa, A Stiepen, M Stolarski, G Strazzulla, HM Tabernero, P Tanga, M Tecsa, J Temple, L Terenzi, M Tessenyi, L Testi, S Thompson, H Thrastarson, BW Tingley, M Trifoglio, J Martin Torres, A Tozzi, D Turrini, R Varley, F Vakili, M de Val-Borro, ML Valdivieso, O Venot, E Villaver, S Vinatier, S Viti, I Waldmann, D Waltham, D Ward-Thompson, R Waters, C Watkins, D Watson, P Wawer, A Wawrzaszek, G White, T Widemann, W Winek, T Wisniowski, R Yelle, Y Yung, SN Yurchenko


Exoplanet atmospheres with EChO: spectral retrievals using EChOSim

EXPERIMENTAL ASTRONOMY 40 (2015) 545-561

JK Barstow, NE Bowles, S Aigrain, LN Fletcher, PGJ Irwin, R Varley, E Pascale


The transit spectra of Earth and Jupiter

ICARUS 242 (2014) 172-187

PGJ Irwin, JK Barstow, NE Bowles, LN Fletcher, S Aigrain, J-M Lee


Modelling of an asteroid photoelectron sheath and implications for a sample return mission

PLANETARY AND SPACE SCIENCE 99 (2014) 103-111

KL Aplin, AJ Macfaden, NE Bowles


Design and performance of the Exoplanet Characterisation Observatory (ECHO) integrated payload

SPACE TELESCOPES AND INSTRUMENTATION 2014: OPTICAL, INFRARED, AND MILLIMETER WAVE 9143 (2014) ARTN 91432E

B Swinyard, M Tessenyi, G Tinetti, I Waldmann, P Eccleston, M Ferlet, R Irshad, T Lim, K Middleton, T Bradshaw, M Crook, T Hunt, B Winter, I Bryson, N Bezawada, W Taylor, N Bowles, E Pascale, G Morgante, E Pace, A Adriani, J-M Reessm, P Drossart, VC du Forestom, M Ivier, R Ottensamer, M Rataj, GR Zapata, J-R Schrader, A Selig, K Isaak, M Linder, L Puig, P Hartogh, C Lovis, G Micela, I Ribas, I Snellen, J-P Beaulieu


Global assessment of pure crystalline plagioclase across the Moon and implications for the evolution of the primary crust

JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS 119 (2014) 1516-1545

KLD Hanna, LC Cheek, CM Pieters, JF Mustard, BT Greenhagen, IR Thomas, NE Bowles


From spectra to atmospheres: Solving the underconstrained retrieval problem for exoplanets

Proceedings of the International Astronomical Union 8 (2013) 275-276

JK Barstow, S Aigrain, PGJ Irwin, N Bowles, LN Fletcher, JM Lee

Spectroscopic observations of transiting exoplanets have provided the first indications of their atmospheric structure and composition. Optimal estimation retrievals have been successfully applied to solar system planets to determine the temperature, composition and aerosol properties of their atmospheres, and have recently been applied to exoplanets. We show the effectiveness of the technique when combined with simulated observations from the proposed space telescope EChO, and also discuss the difficulty of constraining a complex system with sparse data and large uncertainties, using the super-Earth GJ 1214b as an example. Copyright © 2013, International Astronomical Union.


CHASER An Innovative Satellite Mission Concept to Measure the Effects of Aerosols on Clouds and Climate

BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY 94 (2013) 685-+

NO Renno, E Williams, D Rosenfeld, DG Fischer, J Fischer, T Kremic, A Agrawal, MO Andreae, R Bierbaum, R Blakeslee, A Boerner, N Bowles, H Christian, A Cox, J Dunion, A Horvath, X Huang, A Khain, S Kinne, MC Lemos, JE Penner, U Poeschl, J Quaas, E Seran, B Stevens, T Walati, T Wagner


On the potential of the EChO mission to characterize gas giant atmospheres

MNRAS 430 (2013) 1188-1207-1188-1207

JK Barstow, S Aigrain, PGJ Irwin, N Bowles, LN Fletcher, J-M Lee


Thermal infrared emissivity measurements under a simulated lunar environment: Application to the Diviner Lunar Radiometer Experiment

Journal of Geophysical Research E: Planets 117 (2012)

KL Donaldson Hanna, MB Wyatt, IR Thomas, NE Bowles, BT Greenhagen, A Maturilli, J Helbert, DA Paige

We present new laboratory thermal infrared emissivity spectra of the major silicate minerals identified on the Moon measured under lunar environmental conditions and evaluate their application to lunar remote sensing data sets. Thermal infrared spectral changes between ambient and lunar environmental conditions are characterized for the first time over the 400∼1700 cm -1 (6-25 m) spectral range for a fine-particulate mineral suite including plagioclase (albite and anorthite), pyroxene (enstatite and augite), and olivine (forsterite). The lunar environment introduces observable effects in thermal infrared emissivity spectra of fine particulate minerals, which include: (1) a shift in the Christiansen feature (CF) position to higher wave numbers (shorter wavelengths), (2) an increase in the overall spectral contrast, and (3) decreases in the spectral contrast of the reststrahlen bands and transparency features. Our new measurements demonstrate the high sensitivity of thermal infrared emissivity spectra to environmental conditions under which they are measured and provide important constraints for interpreting new thermal infrared data sets of the Moon, including the Diviner Lunar Radiometer Experiment onboard NASA's Lunar Reconnaissance Orbiter. Full resolution laboratory mineral spectra convolved to Diviner's three spectral channels show that spectral shape, CF position and band ratios can be used to distinguish between individual mineral groups and lunar lithologies. The integration of the thermal infrared CF position with near infrared spectral parameters allows for robust mineralogical identifications and provides a framework for future integrations of data sets across two different wavelength regimes. Copyright 2012 by the American Geophysical Union.


A new experimental setup for making thermal emission measurements in a simulated lunar environment.

Rev Sci Instrum 83 (2012) 124502-

IR Thomas, BT Greenhagen, NE Bowles, KL Donaldson Hanna, J Temple, SB Calcutt

One of the key problems in determining lunar surface composition for thermal-infrared measurements is the lack of comparable laboratory-measured spectra. As the surface is typically composed of fine-grained particulates, the lunar environment induces a thermal gradient within the near sub-surface, altering the emission spectra: this environment must therefore be simulated in the laboratory, considerably increasing the complexity of the measurement. Previous measurements have created this thermal gradient by either heating the cup in which the sample sits or by illuminating the sample using a solar-like source. This is the first setup able to measure in both configurations, allowing direct comparisons to be made between the two. Also, measurements across a wider spectral range and at a much higher spectral resolution can be acquired using this new setup. These are required to support new measurements made by the Diviner Lunar Radiometer, the first multi-spectral thermal-infrared instrument to orbit the Moon. Results from the two different heating methods are presented, with measurements of a fine-grained quartz sample compared to previous similar measurements, plus measurements of a common lunar highland material, anorthite. The results show that quartz gives the same results for both methods of heating, as predicted by previous studies, though the anorthite spectra are different. The new calibration pipeline required to convert the raw data into emissivity spectra is described also.


An integrated payload design for the Exoplanet Characterisation Observatory (EChO)

SPACE TELESCOPES AND INSTRUMENTATION 2012: OPTICAL, INFRARED, AND MILLIMETER WAVE 8442 (2012) ARTN 84421G

B Swinyard, G Tinetti, P Eccleston, A Adriani, J-P Beaulieu, A Coustenis, T Belenguer Davila, N Bowles, I Bryson, VC du Foresto, M Ferlet, P Hartogh, P-O Lagage, T Lim, G Malaguti, M Lopez-Morales, G Micela, G Morgante, HU Norgaard-Nielsen, M Ollivier, E Pace, E Pascale, G Piccioni, G Ramos Zapata, J-M Reess, I Ribas, A Sozzetti, J Tennyson, M Tessenyi, MR Swain, B Winter, I Waldmann, G Wright, M-R Zapatero Osorio


Laboratory emissivity measurements of the plagioclase solid solution series under varying environmental conditions

Journal of Geophysical Research E: Planets 117 (2012)

KL Donaldson Hanna, IR Thomas, NE Bowles, BT Greenhagen, CM Pieters, JF Mustard, CRM Jackson, MB Wyatt

New laboratory thermal infrared emissivity measurements of the plagioclase solid solution series over the 1700∼400cm-1 (6-25m) spectral range are presented. Thermal infrared (TIR) spectral changes for fine-particulate samples (0-25m) are characterized for the first time under different laboratory environmental conditions: ambient (terrestrial-like), half-vacuum (Mars-like), vacuum, and vacuum with cooled chamber (lunar-like). Under all environmental conditions the Christiansen Feature (CF) is observed to vary in a systematic way with Na-rich end-member (albite) having a CF position at the highest wave number (shortest wavelength) and the Ca-rich end-member (anorthite) having a CF position with the lowest wave number (longest wavelength). As pressure decreases to<10-3mbar four observations are made: (1) the CF position shifts to higher wave numbers, (2) the spectral contrast of the CF increases relative to the RB, (3) the spectral contrast of the RB in the ∼1200-900 spectral range decreases while the spectral contrast of the RB in the ∼800-400 spectral range either increases or remains the same and (4) the TF disappears. A relationship between the wavelength position of the CF measured under simulated lunar conditions and plagioclase composition (An#) is developed. Although its exact form may evolve with additional data, this linear relationship should be applied to current and future TIR data sets of the Moon. Our new spectral measurements demonstrate how sensitive thermal infrared emissivity spectra of plagioclase feldspars are to the environmental conditions under which they are measured and provide important constraints for interpreting current and future thermal infrared data sets. © 2012 American Geophysical Union. All Rights Reserved.


Investigation of new band parameters with temperature dependence for self-broadened methane gas in the range 9000 to 14,000cm <sup>-1</sup> (0.71 to 1.1μm)

Journal of Quantitative Spectroscopy and Radiative Transfer 113 (2012) 763-782

N Bowles, R Passmore, K Smith, G Williams, S Calcutt, PGJ Irwin

This paper describes new measurements and modelling of the absorption of methane gas, one of the most important gases observed in the atmospheres of the outer planets and Titan, between 9000 and 14,000cm -1 (0.7 to 1.1μm) and compares them with current best available spectral models.A series of methane spectra were measured at the UK's Natural Environment Research Council (NERC) Molecular Spectroscopy Facility (based at the Rutherford Appleton Laboratory, Oxfordshire, UK) using a Brüker 125HR Fourier transform spectrometer. To approximate the conditions found in outer planet atmospheres, the spectra were measured over a wide range of pressures (5bar to 38mbar) and temperatures (290-100K) with path lengths of 19.3, 17.6, 16.0 and 14.4m. The spectra were recorded at a moderate resolution of 0.12cm -1 and then averaged to 10cm -1 resolution prior to fitting a series of increasingly complex band-models including temperature dependence. Using the most complex model, a Goody line distribution with a Voigt line shape and two lower energy state levels, the typical rms residual error in the fit is between 0.01 and 0.02 in the wings of the main absorption bands.The new spectral parameters were then compared with the measured spectra and spectra calculated using existing data and shown to be able to accurately reproduce the measured absorption. The improvement in the temperature dependence included in the model is demonstrated by comparison with existing cold methane spectral data for a typical Jovian path. © 2012 Elsevier Ltd.


Investigation of new band parameters with temperature dependence for self-broadened methane gas in the range 9000 to 14,000 cm -1 (0.71 to 1.1 μm)

Journal of Quantitative Spectroscopy and Radiative Transfer (2012)

N Bowles, R Passmore, K Smith, G Williams, S Calcutt, PGJ Irwin


Lunar Net-a proposal in response to an ESA M3 call in 2010 for a medium sized mission

EXPERIMENTAL ASTRONOMY 33 (2012) 587-644

A Smith, IA Crawford, RA Gowen, R Ambrosi, M Anand, B Banerdt, N Bannister, N Bowles, C Braithwaite, P Brown, J Chela-Flores, T Cholinser, P Church, AJ Coates, T Colaprete, G Collins, G Collinson, T Cook, R Elphic, G Fraser, Y Gao, E Gibson, T Glotch, M Grande, A Griffiths, J Grygorczuk, M Gudipati, A Hagermann, J Heldmann, LL Hood, AP Jones, KH Joy, OB Khavroshkin, G Klingelhoefer, M Knapmeyer, G Kramer, D Lawrence, W Marczewski, S McKenna-Lawlor, K Miljkovic, S Narendranath, E Palomba, A Phipps, WT Pike, D Pullan, J Rask, DT Richard, K Seweryn, S Sheridan, M Sims, M Sweeting, T Swindle, D Talboys, L Taylor, N Teanby, V Tong, S Ulamec, R Wawrzaszek, M Wieczorek, L Wilson, I Wright


EnVision: Taking the pulse of our twin planet

Experimental Astronomy 33 (2012) 337-363

RC Ghail, C Wilson, M Galand, D Hall, C Cochrane, P Mason, J Helbert, F MontMessin, S Limaye, M Patel, N Bowles, D Stam, JE Wahlund, F Rocca, D Waltham, TA Mather, J Biggs, M Genge, P Paillou, K Mitchell, L Wilson, UN Singh

EnVision is an ambitious but low-risk response to ESA's call for a medium-size mission opportunity for a launch in 2022. Venus is the planet most similar to Earth in mass, bulk properties and orbital distance, but has evolved to become extremely hostile to life. EnVision's 5-year mission objectives are to determine the nature of and rate of change caused by geological and atmospheric processes, to distinguish between competing theories about its evolution and to help predict the habitability of extrasolar planets. Three instrument suites will address specific surface, atmosphere and ionosphere science goals. The Surface Science Suite consists of a 2.2 m 2 radar antenna with Interferometer, Radiometer and Altimeter operating modes, supported by a complementary IR surface emissivity mapper and an advanced accelerometer for orbit control and gravity mapping. This suite will determine topographic changes caused by volcanic, tectonic and atmospheric processes at rates as low as 1 mm a -1. The Atmosphere Science Suite consists of a Doppler LIDAR for cloud top altitude, wind speed and mesospheric structure mapping, complemented by IR and UV spectrometers and a spectrophotopolarimeter, all designed to map the dynamic features and compositions of the clouds and middle atmosphere to identify the effects of volcanic and solar processes. The Ionosphere Science Suite uses a double Langmiur probe and vector magnetometer to understand the behaviour and long-term evolution of the ionosphere and induced magnetosphere. The suite also includes an interplanetary particle analyser to determine the delivery rate of water and other components to the atmosphere. © 2011 Springer Science+Business Media B.V.


Lunar regolith thermal gradients and emission spectra: Modeling and validation

Journal of Geophysical Research E: Planets 116 (2011)

L Millán, I Thomas, N Bowles

The retrieval of surface composition from IR measurements of airless bodies requires a model capable of computing the significant thermal gradients present in the top few hundred microns of the regolith. In this study we introduce a model which reproduces most of the features found in controlled experiments made in the simulated lunar environment emission chamber (SLEEC). Although the model presented here is forced by a lower boundary held at a fixed temperature, we conclude that a similar algorithm driven by solar illumination may be used as a forward model to retrieve composition, particle size and effective thermal conductivity from IR measurements of airless bodies. Copyright 2011 by the American Geophysical Union.


Lunar regolith thermal gradients and emission spectra: Modeling and validation

JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS 116 (2011) ARTN E12003

L Millan, I Thomas, N Bowles


Asteroid electrostatic instrumentation and modelling

Journal of Physics: Conference Series 301 (2011)

KL Aplin, NE Bowles, E Urbak, D Keane, EC Sawyer

Asteroid surface material is expected to become photoelectrically charged, and is likely to be transported through electrostatic levitation. Understanding any movement of the surface material is relevant to proposed space missions to return samples to Earth for detailed isotopic analysis. Motivated by preparations for the Marco Polo sample return mission, we present electrostatic modelling for a real asteroid, Itokawa, for which detailed shape information is available, and verify that charging effects are likely to be significant at the terminator and at the edges of shadow regions for the Marco Polo baseline asteroid, 1999JU3. We also describe the Asteroid Charge Experiment electric field instrumentation intended for Marco Polo. Finally, we find that the differing asteroid and spacecraft potentials on landing could perturb sample collection for the short landing time of 20min that is currently planned.

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