| 1. |
- Meech, K. J., et al.
(author)
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EPOXI: Comet 103P/Hartley 2 Observations from a Worldwide Campaign
- 2011
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In: Astrophysical Journal Letters. - London : IOP. - 2041-8213 .- 2041-8205. ; 734:L1, s. 1-9
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Journal article (peer-reviewed)abstract
- Earth- and space-based observations provide synergistic information for space mission encounters by providing data over longer timescales, at different wavelengths and using techniques that are impossible with an in situ flyby. We report here such observations in support of the EPOXI spacecraft flyby of comet 103P/Hartley 2. The nucleus is small and dark, and exhibited a very rapidly changing rotation period. Prior to the onset of activity, the period was ~16.4?hr. Starting in 2010 August the period changed from 16.6?hr to near 19?hr in December. With respect to dust composition, most volatiles and carbon and nitrogen isotope ratios, the comet is similar to other Jupiter-family comets. What is unusual is the dominance of CO 2 -driven activity near perihelion, which likely persists out to aphelion. Near perihelion the comet nucleus was surrounded by a large halo of water-ice grains that contributed significantly to the total water production.
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| 2. |
- Tinetti, Giovanna, et al.
(author)
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The EChO science case
- 2015
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In: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 40:2-3, s. 329-391
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Journal article (peer-reviewed)abstract
- The discovery of almost two thousand exoplanets has revealed an unexpectedly diverse planet population. We see gas giants in few-day orbits, whole multi-planet systems within the orbit of Mercury, and new populations of planets with masses between that of the Earth and Neptune-all unknown in the Solar System. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? How do planetary systems work and what causes the exceptional diversity observed as compared to the Solar System? The EChO (Exoplanet Characterisation Observatory) space mission was conceived to take up the challenge to explain this diversity in terms of formation, evolution, internal structure and planet and atmospheric composition. This requires in-depth spectroscopic knowledge of the atmospheres of a large and well-defined planet sample for which precise physical, chemical and dynamical information can be obtained. In order to fulfil this ambitious scientific program, EChO was designed as a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planet sample within its 4-year mission lifetime. The transit and eclipse spectroscopy method, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allows us to measure atmospheric signals from the planet at levels of at least 10(-4) relative to the star. This can only be achieved in conjunction with a carefully designed stable payload and satellite platform. It is also necessary to provide broad instantaneous wavelength coverage to detect as many molecular species as possible, to probe the thermal structure of the planetary atmospheres and to correct for the contaminating effects of the stellar photosphere. This requires wavelength coverage of at least 0.55 to 11 mu m with a goal of covering from 0.4 to 16 mu m. Only modest spectral resolving power is needed, with R similar to 300 for wavelengths less than 5 mu m and R similar to 30 for wavelengths greater than this. The transit spectroscopy technique means that no spatial resolution is required. A telescope collecting area of about 1 m(2) is sufficiently large to achieve the necessary spectro-photometric precision: for the Phase A study a 1.13 m(2) telescope, diffraction limited at 3 mu m has been adopted. Placing the satellite at L2 provides a cold and stable thermal environment as well as a large field of regard to allow efficient time-critical observation of targets randomly distributed over the sky. EChO has been conceived to achieve a single goal: exoplanet spectroscopy. The spectral coverage and signal-to-noise to be achieved by EChO, thanks to its high stability and dedicated design, would be a game changer by allowing atmospheric composition to be measured with unparalleled exactness: at least a factor 10 more precise and a factor 10 to 1000 more accurate than current observations. This would enable the detection of molecular abundances three orders of magnitude lower than currently possible and a fourfold increase from the handful of molecules detected to date. Combining these data with estimates of planetary bulk compositions from accurate measurements of their radii and masses would allow degeneracies associated with planetary interior modelling to be broken, giving unique insight into the interior structure and elemental abundances of these alien worlds. EChO would allow scientists to study exoplanets both as a population and as individuals. The mission can target super-Earths, Neptune-like, and Jupiter-like planets, in the very hot to temperate zones (planet temperatures of 300-3000 K) of F to M-type host stars. The EChO core science would be delivered by a three-tier survey. The EChO Chemical Census: This is a broad survey of a few-hundred exoplanets, which allows us to explore the spectroscopic and chemical diversity of the exoplanet population as a whole. The EChO Origin: This is a deep survey of a subsample of tens of exoplanets for which significantly higher signal to noise and spectral resolution spectra can be obtained to explain the origin of the exoplanet diversity (such as formation mechanisms, chemical processes, atmospheric escape). The EChO Rosetta Stones: This is an ultra-high accuracy survey targeting a subsample of select exoplanets. These will be the bright "benchmark" cases for which a large number of measurements would be taken to explore temporal variations, and to obtain two and three dimensional spatial information on the atmospheric conditions through eclipse-mapping techniques. If EChO were launched today, the exoplanets currently observed are sufficient to provide a large and diverse sample. The Chemical Census survey would consist of > 160 exoplanets with a range of planetary sizes, temperatures, orbital parameters and stellar host properties. Additionally, over the next 10 years, several new ground- and space-based transit photometric surveys and missions will come on-line (e.g. NGTS, CHEOPS, TESS, PLATO), which will specifically focus on finding bright, nearby systems. The current rapid rate of discovery would allow the target list to be further optimised in the years prior to EChO's launch and enable the atmospheric characterisation of hundreds of planets.
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| 3. |
- Snodgrass, C., et al.
(author)
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The 67P/Churyumov-Gerasimenko observation campaign in support of the Rosetta mission
- 2017
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In: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 375:2097
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Journal article (peer-reviewed)abstract
- We present a summary of the campaign of remote observations that supported the European Space Agency's Rosetta mission. Telescopes across the globe (and in space) followed comet 67P/ Churyumov-Gerasimenko from before Rosetta's arrival until nearly the end of the mission in September 2016. These provided essential data for mission planning, large-scale context information for the coma and tails beyond the spacecraft and a way to directly compare 67P with other comets. The observations revealed 67P to be a relatively 'well-behaved' comet, typical of Jupiter family comets and with activity patterns that repeat from orbit to orbit. Comparison between this large collection of telescopic observations and the in situ results from Rosetta will allow us to better understand comet coma chemistry and structure. This work is just beginning as the mission ends-in this paper, we present a summary of the ground-based observations and early results, and point to many questions that will be addressed in future studies. This article is part of the themed issue 'Cometary science after Rosetta'.
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| 4. |
- Hartogh, P., et al.
(author)
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HIFI observations of water in the atmosphere of comet C/2008 Q3 (Garradd)
- 2010
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:Article Number: L150
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Journal article (peer-reviewed)abstract
- High-resolution far-infrared and sub-millimetre spectroscopy of water lines is an important tool to understand the physical and chemical properties of cometary atmospheres. We present observations of several rotational ortho- and para-water transitions in comet C/2008 Q3 (Garradd) performed with HIFI on Herschel. These observations have provided the first detection of the 2(12)-1(01) (1669 GHz) ortho and 1(11)-0(00) (1113 GHz) para transitions of water in a cometary spectrum. In addition, the ground-state transition 1(10)-1(01) at 557 GHz is detected and mapped. By detecting several water lines quasi-simultaneously and mapping their emission we can constrain the excitation parameters in the coma. Synthetic line profiles are computed using excitation models which include excitation by collisions, solar infrared radiation, and radiation trapping. We obtain the gas kinetic temperature, constrain the electron density profile, and estimate the coma expansion velocity by analyzing the map and line shapes. We derive water production rates of 1.7-2.8 x 10(28) s(-1) over the range r(h) = 1.83-1.85 AU.
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| 5. |
- Carter, Aarynn L., et al.
(author)
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A benchmark JWST near-infrared spectrum for the exoplanet WASP-39 b
- 2024
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In: Nature Astronomy. - 2397-3366. ; In Press
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Journal article (peer-reviewed)abstract
- A combined analysis of datasets across four JWST instrument modes provides a benchmark transmission spectrum for the Saturn-mass WASP-39 b. The broad wavelength range and high resolution constrain orbital and stellar parameters to below 1%.
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| 6. |
- Brahm, R., et al.
(author)
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HATS-43b, HATS-44b, HATS-45b, and HATS-46b : Four Short-period Transiting Giant Planets in the Neptune-Jupiter Mass Range
- 2018
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In: Astronomical Journal. - : American Astronomical Society. - 0004-6256 .- 1538-3881. ; 155:3
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Journal article (peer-reviewed)abstract
- We report the discovery of four short-period extrasolar planets transiting moderately bright stars from photometric measurements of the HATSouth network coupled to additional spectroscopic and photometric follow-up observations. While the planet masses range from 0.26 to 0.90 M-J, the radii are all approximately a Jupiter radii, resulting in a wide range of bulk densities. The orbital period of the planets ranges from 2.7 days to 4.7 days, with HATS-43b having an orbit that appears to be marginally non-circular (e = 0.173 +/- 0.089). HATS-44 is notable for having a high metallicity ([Fe/H]= 0.320 +/- 0.071). The host stars spectral types range from late F to early K, and all of them are moderately bright (13.3 < V < 14.4), allowing the execution of future detailed follow-up observations. HATS-43b and HATS-46b, with expected transmission signals of 2350 ppm and 1500 ppm, respectively, are particularly well suited targets for atmospheric characterization via transmission spectroscopy.
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| 7. |
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| 8. |
- Bento, J., et al.
(author)
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HATS-22b, HATS-23b and HATS-24b : three new transiting super-Jupiters from the HATSouth project
- 2017
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In: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 468:1, s. 835-848
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Journal article (peer-reviewed)abstract
- We report the discovery of three moderately high-mass transiting hot Jupiters from the HATSouth survey: HATS-22b, HATS-23b and HATS-24b. These planets add to the number of known planets in the similar to 2MJ regime. HATS-22b is a 2.74 +/- 0.11MJ mass and 0.953(-0.029)(+0.048) R-J radius planet orbiting a V = 13.455 +/- 0.040 sub-solar mass (M-* = 0.759 +/- 0.019M(circle dot); R-* = 0.759 +/- 0.019 R-circle dot) K-dwarf host star on an eccentric (e = 0.079 +/- 0.026) orbit. This planet's high planet-to-stellar mass ratio is further evidence that migration mechanisms for hot Jupiters may rely on exciting orbital eccentricities that bring the planets closer to their parent stars followed by tidal circularization. HATS-23b is a 1.478 +/- 0.080M(J) mass and 1.69 +/- 0.24 R-J radius planet on a grazing orbit around a V = 13.901 +/- 0.010 G-dwarf with properties very similar to those of the Sun (M* = 1.115 +/- 0.054; R-* = 1.145 +/- 0.070). HATS24b orbits a moderately bright V = 12.830 +/- 0.010 F-dwarf star (M-* = 1.218 +/- 0.036M circle dot; R-* = 1.194(-0.041)(+0.066) R circle dot). This planet has a mass of 2.39+0.21 -0.12MJ and an inflated radius of 1.516(-0.065)(+0.085) R-J.
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| 9. |
- de Val-Borro, M., et al.
(author)
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HATS-31B THROUGH HATS-35B : FIVE TRANSITING HOT JUPITERS DISCOVERED BY THE HATSOUTH SURVEY
- 2016
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In: Astronomical Journal. - : American Astronomical Society. - 0004-6256 .- 1538-3881. ; 152:6
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Journal article (peer-reviewed)abstract
- We report the discovery of five new transiting hot-Jupiter planets discovered by the HATSouth survey, HATS-31b through HATS-35b. These planets orbit moderately bright stars with V magnitudes within the range of 11.9-14.4 mag while the planets span a range of masses of. 0.88-1.22 M-J. and have somewhat inflated radii between 1.23 and 1.64 R-J. These planets can be classified as typical hot Jupiters, with HATS-31b and HATS-35b being moderately inflated gas giant planets with radii of 1.64 +/- 0.22 R-J and 1.464(-0.044)(+0.069) R-J, respectively, that can be used to constrain inflation mechanisms. All five systems present a higher Bayesian evidence for a fixed-circular-orbit model than for an eccentric orbit. The orbital periods range from 1.8209993 +/- 0.0000016 day for HATS-35b) to 3.377960 +/- 0.000012 day for HATS-31b. Additionally, HATS-35b orbits a relatively young F star with an age of 2.13 +/- 0.51 Gyr. We discuss the analysis to derive the properties of these systems and compare them in the context of the sample of well-characterized transiting hot Jupiters known to date.
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| 10. |
- Ginsburg, Adam, et al.
(author)
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astroquery: An Astronomical Web-querying Package in Python
- 2019
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In: Astronomical Journal. - : American Astronomical Society. - 1538-3881 .- 0004-6256. ; 157:3
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Journal article (peer-reviewed)abstract
- Astroquery is a collection of tools for requesting data from databases hosted on remote servers with interfaces exposed on the Internet, including those with web pages but without formal application program interfaces. These tools are built on the Python requests package, which is used to make HTTP requests, and astropy, which provides most of the data parsing functionality. astroquery modules generally attempt to replicate the web page interface provided by a given service as closely as possible, making the transition from browser-based to command-line interaction easy. astroquery has received significant contributions from throughout the astronomical community, including several from telescope archives. astroquery enables the creation of fully reproducible workflows from data acquisition through publication. This paper describes the philosophy, basic structure, and development model of the astroquery package. The complete documentation for astroquery can be found at http://astroquery.readthedocs.io/.
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