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Design and Construction of Absorption Cells for Precision Radial Velocities in the K Band Using Methane Isotopologues

Anglada-Escudé, Guillem and Plavchan, Peter and Mills, Sean and Gao, Peter and García-Berríos, Edgardo and Lewis, Nathan S. and Sung, Keeyoon and Ciardi, David and Beichman, Chas and Brinkworth, Carolyn and Johnson, John and Davison, Cassy and White, Russel and Prato, Lisa (2012) Design and Construction of Absorption Cells for Precision Radial Velocities in the K Band Using Methane Isotopologues. Publications of the Astronomical Society of the Pacific, 124 (916). pp. 586-597. ISSN 0004-6280. doi:10.1086/666489.

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We present a method to optimize absorption cells for precise wavelength calibration in the near-infrared. We apply it to design and optimize methane isotopologue cells for precision radial velocity measurements in the K band. We also describe the construction and installation of two such cells for the CSHELL spectrograph at NASA’s IRTF. We have obtained their high-resolution laboratory spectra, which we can then use in precision radial velocity measurements and which can also have other applications. In terms of obtainable RV precision, methane should outperform other proposed cells, such as the ammonia cell (^(14)NH_3) recently demonstrated on CRIRES/VLT. The laboratory spectra of the ammonia and methane cells show strong absorption features in the H band that could also be exploited for precision Doppler measurements. We present spectra and preliminary radial velocity measurements obtained during our first-light run. These initial results show that a precision down to 20-30 m s^(-1)can be obtained using a wavelength interval of only 5 nm in the K band and S/N ∼ 150. This supports the prediction that a precision down to a few meters per second can be achieved on late-M dwarfs using the new generation of NIR spectrographs, thus enabling the detection of terrestrial planets in their habitable zones. Doppler measurements in the NIR can also be used to mitigate the radial velocity jitter due to stellar activity, enabling more efficient surveys on young active stars.

Item Type:Article
Related URLs:
URLURL TypeDescription
Anglada-Escudé, Guillem0000-0002-3645-5977
Plavchan, Peter0000-0002-8864-1667
Mills, Sean0000-0002-4535-6241
Gao, Peter0000-0002-8518-9601
Lewis, Nathan S.0000-0001-5245-0538
Ciardi, David0000-0002-5741-3047
Beichman, Chas0000-0002-5627-5471
Johnson, John0000-0001-9808-7172
White, Russel0000-0001-5313-7498
Additional Information:© 2012 The Astronomical Society of the Pacific. Received 2011 August 18; accepted 2012 April 24; published 2012 May 22. Both G. Anglada-Escudé and P. Plavchan contributed equally to this work. G. A. would like to acknowledge the Carnegie Postdoctoral Fellowship Program and the support provided by the NASA Astrobiology Institute grant NNA09DA81A. Peter Plavchan would like acknowledge Wes Traub and Stephen Unwin for funding provided by the Jet Propulsion Laboratory’s (JPL’s) Center for Exoplanet Science and NASA Exoplanet Science Institute. K. Sung acknowledges the Planetary Atmospheric Research Program to support the laboratory spectroscopic calibrations. Part of the research at the JPL and California Institute of Technology was performed under contracts with National Aeronautics and Space Administration. We thank Anu Dudhia for making the Reference Forward Model code available to us and for his assistance with adapting it for gas cell spectral calculations. The stellar synthetic spectra were graciously provided by Peter Hauschildt (University of Hamburg) and the PHOENIX group. We also thank Linda Brown from JPL’s Laboratory Studies and Modeling group and Pin Chen from the Planetary Chemistry and Astrobiology group for their advice and support using the Fourier-transformed infrared spectrometer. We would like to thank Paul Butler (Carnegie Institution of Washington) and Gilian Nave (NIST) for their advice in gas optimization parameters and molecular spectroscopy in general. We would like to thank Stephen Kane (NExScI), Kaspar von Braun (NExScI), and Steve Osterman (University of Colorado) for their valuable discussions. We also thank John Rayner, Morgan Bonnet, George Koenig, and Alan Tokunaga from IfA, Hawaii, for their support during the CSHELL/IRTF cell design review, integration, and commissioning. We thank Rick Gerhart (California Institute of Technology), Scot Howell (Mindrum Precision), and Thurston Levy (Glass Instruments, Inc.) for their work in helping construct and fill the gas cells, as well as Joeff Zolkower (California Institute of Technology) for mechanical engineering advise.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:Exoplanets
Issue or Number:916
Record Number:CaltechAUTHORS:20120801-111847565
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Official Citation:Design and Construction of Absorption Cells for Precision Radial Velocities in the K Band Using Methane Isotopologues Guillem Anglada-Escudé, Peter Plavchan, Sean Mills, Peter Gao, Edgardo García-Berríos, Nathan S. Lewis, Keeyoon Sung, David Ciardi, Chas Beichman, Carolyn Brinkworth, John Johnson, Cassy Davison, Russel White and Lisa Prato Publications of the Astronomical Society of the Pacific , Vol. 124, No. 916 (June 2012), pp. 586-597 Published by: The University of Chicago Press on behalf of the Astronomical Society of the Pacific Article DOI: 10.1086/666489 Article Stable URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:32835
Deposited By: Jason Perez
Deposited On:01 Aug 2012 18:46
Last Modified:09 Nov 2021 21:30

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