Design and construction of absorption cells for precision radial velocities in the K band using methane isotopologues

Anglada-Escude, Guillem and Plavchan, Peter and Mills, Sean and Gao, Peter and Garcia-Berrios, 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


We present a method to optimize absorption cells for precise wavelength calibration in the nearinfrared. 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 ( 14NH 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.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 20 Jun 2017 05:48
Last Modified: 27 Jun 2017 01:03
Uncontrolled Keywords: Wavelength calibration; radial velocities; methane isotopologues
Fields of Research (2008): 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020102 Astronomical and Space Instrumentation
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5199 Other physical sciences > 519999 Other physical sciences not elsewhere classified
Socio-Economic Objectives (2008): E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
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