The GMT-Consortium Large Earth Finder (G-CLEF): an optical Echelle spectrograph for the Giant Magellan Telescope (GMT)

Szentgyorgyi, Andrew; Baldwin, D.F.; Barnes, Stuart; Bean, Jacob L.; Ben-Ami, Sagi; Brennan, Patricia; Budynkiewicz, Jamie A.; Chun, Moo Young; Conroy, Charlie; Crane, Jeffrey D.; Evans, I. N.; Evans, Janet D.; Foster, Jeff; Frebel, Anna; Gauron, Thomas; Guzmán, Dani; Hare, Tyson; Jang, Bi-Ho; Jang, Jeong Gyun; Jordán, Andrés; Kim, Jihun; Kim, Kang Miin; Oliveira, Claudia Mendes Mendes De; López‐Morales, Mercedes; McCracken, K. G.; McMuldroch, Stuart; Miller, Joseph B.; Mueller, Mark; Oh, Jae Sok; Onyuksel, Cem; Ordway, Mark; Park, Byeong Gon; Park, Chan; Park, Sung‐Joon; Paxson, Charles; Phillips, David F.; Plummer, David A.; Podgorski, William; Seifahrt, Andreas; Stark, Daniel P.; Steiner, J. E.; Uomoto, Alan; Walsworth, Ronald L.; Yu, Young Sam

doi:10.1117/12.2233506

Cited by 35 publications

(21 citation statements)

References 26 publications

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“…Future advances in the exoplanet census and RV instruments will expand the number of systems amenable to similar studies. Next-generation RV facilities at large telescopes such as VLT/ ESPRESSO (González Hernández et al 2017), Keck/KPF (Gibson et al 2016), and GMT/GCLEF (Szentgyorgyi et al 2016) will enable RV measurements of a large sample of faint Kepler planet hosts, including many TTV-active systems. Also, ESA's PLATO mission (Rauer 2013) will conduct a transit survey over ≈2000deg 2 for 2-3 years and add to the sample of planets with long baseline photometry.…”

Section: Discussionmentioning

confidence: 99%

Dynamics and Formation of the Near-resonant K2-24 System: Insights from Transit-timing Variations and Radial Velocities

Petigura

Benneke

Batygin

et al. 2018

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While planets between the size of Uranus and Saturn are absent within the solar system, the star K2-24 hosts two such planets, K2-24b and c, with radii equal to 5.4 Å R and 7.5 Å R , respectively. The two planets have orbital periods of 20.9days and 42.4days, residing only 1% outside the nominal 2:1 mean-motion resonance. In this work, we present results from a coordinated observing campaign to measure planet masses and eccentricities that combines radial velocity measurements from Keck/HIRES and transit-timing measurements from K2 and Spitzer. K2-24b and c have low, but nonzero, eccentricities of~ẽ e 0.08 1 2. The low observed eccentricities provide clues to the formation and dynamical evolution of K2-24b and K2-24c, suggesting that they could be the result of stochastic gravitational interactions with a turbulent protoplanetary disk, among other mechanisms. K2-24b and c are M , respectively; K2-24c is 20% less massive than K2-24b, despite being 40% larger. Their large sizes and low masses imply large envelope fractions, which we estimate at -+ 26 3 3 % and -+ 52 3 5 %. In particular, K2-24c's large envelope presents an intriguing challenge to the standard model of core-nucleated accretion that predicts the onset of runaway accretion when f env ≈50%.

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Section: Discussionmentioning

confidence: 99%

Dynamics and Formation of the Near-resonant K2-24 System: Insights from Transit-timing Variations and Radial Velocities

Petigura

Benneke

Batygin

et al. 2018

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“…The next generation of radial velocity spectrographs aspire to measure signals smaller than 10 cm/s. For example, the Giant Magellan Telescope‐Consortium Large Earth Finder has a precision goal of ~10 cm/s [ Szentgyorgyi et al ., ]. Additionally, the Eschelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations on the European Southern Observatory's Very Large Telescope array should have a precision of radial velocity variations of a few centimeters per second [ Pepe et al ., ].…”

Section: Future Outlookmentioning

confidence: 99%

The sustainability of habitability on terrestrial planets: Insights, questions, and needed measurements from Mars for understanding the evolution of Earth‐like worlds

et al. 2016

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What allows a planet to be both within a potentially habitable zone and sustain habitability over long geologic time? With the advent of exoplanetary astronomy and the ongoing discovery of terrestrial‐type planets around other stars, our own solar system becomes a key testing ground for ideas about what factors control planetary evolution. Mars provides the solar system's longest record of the interplay of the physical and chemical processes relevant to habitability on an accessible rocky planet with an atmosphere and hydrosphere. Here we review current understanding and update the timeline of key processes in early Mars history. We then draw on knowledge of exoplanets and the other solar system terrestrial planets to identify six broad questions of high importance to the development and sustaining of habitability (unprioritized): (1) Is small planetary size fatal? (2) How do magnetic fields influence atmospheric evolution? (3) To what extent does starting composition dictate subsequent evolution, including redox processes and the availability of water and organics? (4) Does early impact bombardment have a net deleterious or beneficial influence? (5) How do planetary climates respond to stellar evolution, e.g., sustaining early liquid water in spite of a faint young Sun? (6) How important are the timescales of climate forcing and their dynamical drivers? Finally, we suggest crucial types of Mars measurements (unprioritized) to address these questions: (1) in situ petrology at multiple units/sites; (2) continued quantification of volatile reservoirs and new isotopic measurements of H, C, N, O, S, Cl, and noble gases in rocks that sample multiple stratigraphic sections; (3) radiometric age dating of units in stratigraphic sections and from key volcanic and impact units; (4) higher‐resolution measurements of heat flux, subsurface structure, and magnetic field anomalies coupled with absolute age dating. Understanding the evolution of early Mars will feed forward to understanding the factors driving the divergent evolutionary paths of the Earth, Venus, and thousands of small rocky extrasolar planets yet to be discovered.

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“…1.9, [49]: multi-object spectrograph for Astrophysics, inter galactic medium, and cosmology. G-CLEF [50]: GMT consortium large earth finder; GMTIFS [51]: GMT integral-field spectrograph; GMACS [52]: GMT multi-object astronomical and cosmological spectrograph; GMTNIRS [53]: GMT near-infrared spectrograph. NFIRAOS [54]: narrow-field infrared AO system; IRIS [55]:infrared imager and spectrograph; IRMS [56]:infrared multi-object spectrograph; TMT-AGE [57]: TMT analyzer for galaxies in the early universe; WFOS: wide-field optical spectrometer.…”

Section: Error Budget In Aomentioning

confidence: 99%

Projected Pupil Plane Pattern: an alternative LGS wavefront sensing technique

Yang

Bharmal

Myers

2018

Monthly Notices of the Royal Astronomical Society

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any wayThe full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Abstract For the next generation of extremely large telescopes, Focal Anisoplanatism (FA) renders single Laser Guide Star AO useless. Here we analyze a novel LGS alternative configuration with corresponding wavefront sensing and reconstruction method, termed Projected Pupil Plane Pattern, to solve the problem of Focal Anisoplanatism. With PPPP, turbulence is sensed during uplink by a laser beam projected as a collimated beam from the whole telescope primary mirror. Phase changes due to the turbulence introduce intensity variations that then increase in amplitude with propagation distance. By observing the distribution of intensity at two distant planes, the Transport-of-Intensity equation can be used to determine the phase aberration encountered during the uplink path. A simple imaging camera can then be used to measure the wavefront by imaging the backscattered light patterns. We have successfully demonstrated PPPP works both by simulation and laboratory experiment, where we find that PPPP can achieve equivalent performance to a SH WFS associated with a NGS. However it is shown that the main problem of PPPP is its low Signal-to-Noise Ratio if a 20 W laser is used. To reduce the requirement for high laser power, an alternative reconstructor based upon nonlinear Artificial Neural Networks has been developed, and provides a wavefront with measurement error around 160 nm RMS with a single 200 W laser on a 4-m diameter telescope. PPPP is therefore ready for a practical onsky test, which we are currently undertaking at Electro Optical Systems (EOS) Debris Laser Ranging (DLR) system, Australia. Supervisors: Nazim Bharmal and Richard Myers ii Acknowledgements I acknowledge financial support from China Scholarship Council (CSC) for covering the living expenses during my first three years of study, and from Durham University for my last year, as well as the funding of STFC for my PhD project.

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The GMT-Consortium Large Earth Finder (G-CLEF): an optical Echelle spectrograph for the Giant Magellan Telescope (GMT)

Cited by 35 publications

References 26 publications

Dynamics and Formation of the Near-resonant K2-24 System: Insights from Transit-timing Variations and Radial Velocities

Dynamics and Formation of the Near-resonant K2-24 System: Insights from Transit-timing Variations and Radial Velocities

The sustainability of habitability on terrestrial planets: Insights, questions, and needed measurements from Mars for understanding the evolution of Earth‐like worlds

Projected Pupil Plane Pattern: an alternative LGS wavefront sensing technique

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