Author
Maire N. Gorman
Other affiliations: University of New South Wales, University College London
Bio: Maire N. Gorman is an academic researcher from Aberystwyth University. The author has contributed to research in topics: Spectral line & Multireference configuration interaction. The author has an hindex of 8, co-authored 15 publications receiving 552 citations. Previous affiliations of Maire N. Gorman include University of New South Wales & University College London.
Papers
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TL;DR: The ExoMol database as mentioned in this paper provides extensive line lists of molecular transitions which are valid over extended temperature ranges, including lifetimes of individual states, temperature-dependent cooling functions, Lande g-factors, partition functions, cross sections, k-coefficients and transition dipoles with phase relations.
421 citations
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TL;DR: The ExoMol database as mentioned in this paper provides molecular data for spectroscopic studies of hot atmospheres, including 80 molecules and 190 isotopologues with over 700 billion transitions.
Abstract: The ExoMol database ( www.exomol.com ) provides molecular data for spectroscopic studies of hot atmospheres. While the data are intended for studies of exoplanets and other astronomical bodies, the dataset is widely applicable. The basic form of the database is extensive line lists; these are supplemented with partition functions, state lifetimes, cooling functions, Lande g-factors, temperature-dependent cross sections, opacities, pressure broadening parameters, k-coefficients and dipoles. This paper presents the latest release of the database which has been expanded to consider 80 molecules and 190 isotopologues totaling over 700 billion transitions. While the spectroscopic data are concentrated at infrared and visible wavelengths, ultraviolet transitions are being increasingly considered in response to requests from observers. The core of the database comes from the ExoMol project which primarily uses theoretical methods, albeit usually fine-tuned to reproduce laboratory spectra, to generate very extensive line lists for studies of hot bodies. The data have recently been supplemented by line lists derived from direct laboratory observations, albeit usually with the use of ab initiotransition intensities. A major push in the new release is towards accurate characterisation of transition frequencies for use in high resolution studies of exoplanets and other bodies.
117 citations
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TL;DR: In this article, a comprehensive line list for phosphorus monoxide and phosphorus monosulphide in their electronic ground state is presented based on new ab initio potential energy (PEC), spin-orbit (SOC) and dipole moment (DMC) curves computed using the MRCI+Q-r method with aug-cc-pwCV5Z and aug-c-pV5Z basis sets.
Abstract: Comprehensive line lists for phosphorus monoxide ($^{31}$P$^{16}$O) and phosphorus monosulphide ($^{31}$P$^{32}$S) in their $X$ $^2\Pi$ electronic ground state are presented. The line lists are based on new ab initio potential energy (PEC), spin-orbit (SOC) and dipole moment (DMC) curves computed using the MRCI+Q-r method with aug-cc-pwCV5Z and aug-cc-pV5Z basis sets. The nuclear motion equations (i.e. the rovibronic Schrodinger equations for each molecule) are solved using the program Duo. The PECs and SOCs are refined in least-squares fits to available experimental data. Partition functions, $Q(T)$, are computed up to $T=$ 5000 K, the range of validity of the line lists. These line lists are the most comprehensive available for either molecule. The characteristically sharp peak of the $Q$-branches from the spin-orbit split components give useful diagnostics for both PO and PS in spectra at infrared wavelengths. These line lists should prove useful for analysing observations and setting up models of environments such as brown dwarfs, low-mass stars, O-rich circumstellar regions and potentially for exoplanetary retrievals. Since PS is yet to be detected in space, the role of the two lowest excited electronic states ($a$ $^4\Pi$ and $B$ $^2\Pi$) are also considered. An approximate line list for the PS $X - B$ electronic transition, which predicts a number of sharp vibrational bands in the near ultraviolet, is also presented. he line lists are available from the CDS (this http URL) and ExoMol (this http URL) databases.
48 citations
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TL;DR: In this article, the authors presented a line list for the main isotopologues of silicon monohydride (SiH, SiD, SiH, ²µSiH and ² µµ SiD), which is applicable up to temperatures of 5000 K, making them relevant to exoplanetary atmospheres and cool stars.
Abstract: SiH has long been observed in the spectrum of our Sun and other cool stars. Computed line lists for the main isotopologues of silicon monohydride, ²⁸SiH, ²⁹SiH, ³⁰SiH and ²⁸SiD are presented. These line lists consider rotation–vibration transitions within the ground X²Π electronic state as well as transitions to the low-lying A²Δ and a⁴Σ⁻ states. Ab initio potential energy (PECs) and dipole moment curves along with spin–orbit and electronic angular momentum couplings between them are calculated using the multireference configuration interaction level of theory with the MOLPRO package. The PEC for the ground X²Π state is refined to available experimental data with a typical accuracy of around 0.01 cm⁻¹ or better. The ²⁸SiH line list includes 11 785 rovibronic states and 1724 841 transitions with associated Einstein-A coefficients for angular momentum J up to 82.5 and covering wavenumbers up to 31 340 cm⁻¹ (λ < 0.319 μm). Spectra are simulated using the new line list and comparisons made with various experimental spectra. These line lists are applicable up to temperatures of 5000 K, making them relevant to astrophysical objects such as exoplanetary atmospheres and cool stars and opening up the possibility of detection in the interstellar medium. These line lists, called SiGHTLY, are available at the ExoMol (www.exomol.com) and CDS data base websites.
28 citations
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TL;DR: In the ORBYTS project as discussed by the authors, students between the ages of 15 and 18 have been performing original research associated with the exploration of space since January 2016, where the student groups have each been led by junior researchers.
Abstract: Involving students in state-of-the-art research from an early age eliminates the idea that science is only for the scientists and empowers young people to explore STEM (Science, Technology, Engineering and Maths) subjects. It is also a great opportunity to dispel harmful stereotypes about who is suitable for STEM careers, while leaving students feeling engaged in modern science and the scientific method.
As part of the Twinkle Space Mission's educational programme, EduTwinkle, students between the ages of 15 and 18 have been performing original research associated with the exploration of space since January 2016. The student groups have each been led by junior researchers—PhD and post-doctoral scientists—who themselves benefit substantially from the opportunity to supervise and manage a research project. This research aims to meet a standard for publication in peer-reviewed journals. At present the research of two ORBYTS teams have been published, one in the Astrophysical Journal Supplement Series and another in JQSRT; we expect more papers to follow.
Here we outline the necessary steps for a productive scientific collaboration with school children, generalising from the successes and downfalls of the pilot ORBYTS projects.
26 citations
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28,685 citations
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TL;DR: The ExoMol database as mentioned in this paper provides extensive line lists of molecular transitions which are valid over extended temperature ranges, including lifetimes of individual states, temperature-dependent cooling functions, Lande g-factors, partition functions, cross sections, k-coefficients and transition dipoles with phase relations.
421 citations
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TL;DR: The HITRAN database is a compilation of molecular spectroscopic parameters as discussed by the authors , which is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres).
Abstract: The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. This paper describes the contents of the 2020 quadrennial edition of HITRAN. The HITRAN2020 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2016 (including its updates during the intervening years). All five components of HITRAN have undergone major updates. In particular, the extent of the updates in the HITRAN2020 edition range from updating a few lines of specific molecules to complete replacements of the lists, and also the introduction of additional isotopologues and new (to HITRAN) molecules: SO, CH3F, GeH4, CS2, CH3I and NF3. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. Also, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often featuring sub-percent uncertainties. Broadening parameters associated with the ambient pressure of water vapor were introduced to HITRAN for the first time and are now available for several molecules. The HITRAN2020 edition continues to take advantage of the relational structure and efficient interface available at www.hitran.org and the HITRAN Application Programming Interface (HAPI). The functionality of both tools has been extended for the new edition.
393 citations
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TL;DR: The ARIEL mission as mentioned in this paper was designed to observe a large number of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25-7.8 μm spectral range and multiple narrow-band photometry in the optical.
Abstract: Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.
298 citations
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TL;DR: In this article, a line list for H216O is presented, which includes transitions between rotational-vibrational energy levels up to 41 000 cm-1 and rotational angular momentum J up to 72.
Abstract: A new line list for H216O is presented. This line list, which is called POKAZATEL, includes transitions between rotational-vibrational energy levels up to 41 000 cm-1and is the most complete to date. The potential energy surface (PES) used for producing the line list was obtained by fitting a high-quality ab initio PES to experimental energy levels with energies of 41 000 cm-1and for rotational excitations up to J = 5. The final line list comprises all energy levels up to 41 000 cm-1and rotational angular momentum J up to 72. An accurate ab initio dipole moment surface was used for the calculation of line intensities and reproduces high-precision experimental intensity data with an accuracy close to 1 per cent. The final line list uses empirical energy levels, whenever they are available, to ensure that line positions are reproduced as accurately as possible. The POKAZATEL line list contains over 5 billion transitions and is available from the ExoMol website (www.exomol.com) and the CDS data base.
287 citations