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

Anglada-Escudé, G.; Plavchan, Peter; Mills, Sean M.; Gao, Peter; García-Berríos, Edgardo; Lewis, Nathan S.; Sung, Keeyoon; Ciardi, David R.; Beichman, C. A.; Brinkworth, Carolyn; Johnson, John Asher; Davison, C.; White, R. J.; Prato, L.

doi:10.1086/666489

Cited by 41 publications

(25 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our team has recently developed a methane isotopologue gas cell that offers a high absorption line density in the NIR regime to achieve RV measurements of the order of a few m s −1 with the limited spectral grasp of CSHELL at the NASA InfraRed Telescope Facility (IRTF; Anglada-Escudé et al 2012;Plavchan et al 2013), as well as an iterative algorithm that allows for the simultaneous solving of the wavelength solution, the construction of an empirical stellar spectrum, and the measurement of stellar RVs (P.Gao et al, submitted to PASP). In this paper, we present the results of an NIR RV survey of 32 late-type, nearby stars using CSHELL at the IRTF using this new RV extraction pipeline.…”

Section: Introductionmentioning

confidence: 99%

A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

Gagné

Plavchan

Gao

et al. 2016

ApJ

Self Cite

233

View full text Add to dashboard Cite

We present the results of a precise near-infrared (NIR) radial velocity (RV) survey of 32 low-mass stars with spectral types K2-M4 using CSHELL at the NASA InfraRed Telescope Facility in the K band with an isotopologue methane gas cell to achieve wavelength calibration and a novel, iterative RV extraction method. We surveyed 14 members of young (≈25-150 Myr) moving groups, the young field star εEridani, and 18 nearby (<25 pc) low-mass stars and achieved typical single-measurement precisions of 8-15 m s −1 with a long-term stability of 15-50 m s −1 over longer baselines. We obtain the best NIR RV constraints to date on 27 targets in our sample, 19 of which were never followed by high-precision RV surveys. Our results indicate that very active stars can display long-term RV variations as low as ∼25-50 m s −1 at ≈2.3125 μm, thus constraining the effect of jitter at these wavelengths. We provide the first multiwavelength confirmation of GJ876bc and independently retrieve orbital parameters consistent with previous studies. We recovered RV variabilities for HD160934AB and GJ725AB that are consistent with their known binary orbits, and nine other targets are candidate RV variables with a statistical significance of 3σ-5σ. Our method, combined with the new iSHELL spectrograph, will yield long-term RV precisions of 5 m s −1 in the NIR, which will allow the detection of super-Earths near the habitable zone of mid-M dwarfs.

show abstract

Section: Introductionmentioning

confidence: 99%

A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

Gagné

Plavchan

Gao

et al. 2016

ApJ

Self Cite

233

View full text Add to dashboard Cite

show abstract

“…We recently presented our technique for achieving ∼50 m s −1 on late-K and early-M dwarfs using the CSHELL NIR spectrograph on the Infrared Telescope Facility (IRTF; Crockett et al 2011). Anglada-Escude et al (2012) also show very promising results with their successful efforts at obtaining 20-30 m s −1 precision in the K band, also on CSHELL, using a methane isotopologue gas cell.…”

Section: Introductionmentioning

confidence: 99%

A Search for Giant Planet Companions to T Tauri Stars

Crockett

Mahmud

Prato

et al. 2012

ApJ

View full text Add to dashboard Cite

We present results from an ongoing multiwavelength radial velocity (RV) survey of the Taurus-Auriga star-forming region as part of our effort to identify pre-main-sequence giant planet hosts. These 1-3 Myr old T Tauri stars present significant challenges to traditional RV surveys. The presence of strong magnetic fields gives rise to large, cool star spots. These spots introduce significant RV jitter which can mimic the velocity modulation from a planet-mass companion. To distinguish between spot-induced and planet-induced RV modulation, we conduct observations at ∼6700 Å and ∼2.3 μm and measure the wavelength dependence (if any) in the RV amplitude. CSHELL observations of the known exoplanet host Gl 86 demonstrate our ability to detect not only hot Jupiters in the near-infrared but also secular trends from more distant companions. Observations of nine very young stars reveal a typical reduction in RV amplitude at the longer wavelengths by a factor of ∼2-3. While we cannot confirm the presence of planets in this sample, three targets show different periodicities in the two wavelength regions. This suggests different physical mechanisms underlying the optical and the K-band variability.

show abstract

“…A Hawaii 2RG array records 29 cross-dispersed echelle orders (m = 212 − 240) spanning this spectral range. A methane isotopologue ( 13 CH 4 ) gas cell in the calibration unit with 90% continuum throughput is used to provide a common optical path wavelength reference and to constrain the variable line spread function (LSF) of the spectrograph (Anglada-Escudé et al 2012;Plavchan et al 2013). To minimize errors in the barycenter correction and telluric optical depths of individual spectra, integration times are limited to 5 minutes.…”

Section: Observationsmentioning

confidence: 99%

Precise Radial Velocities of Cool Low-mass Stars with iSHELL

Cale

Plavchan

LeBrun

et al. 2019

Self Cite

View full text Add to dashboard Cite

The coolest dwarf stars are intrinsically faint at visible wavelengths and exhibit rotationally modulated stellar activity from spots and plages. It is advantageous to observe these stars at near infrared (NIR) wavelengths (1-2.5 µm) where they emit the bulk of their bolometric luminosity and are most quiescent. In this work we describe our methodology and results in obtaining precise radial velocity (RV) measurements of low mass stars using K-band spectra taken with the R~80,000 iSHELL spectrograph and the NASA Infrared Telescope Facility (IRTF) using a methane isotopologue gas cell in the calibration unit. Our novel analysis pipeline extracts RVs by minimizing the RMS of the residuals between the observed spectrum and a forward model. The model accounts for the gas cell, tellurics, blaze function, multiple sources of quasi-sinusoidal fringing, and line spread function of the spectrograph (LSF). The stellar template is derived iteratively using the target observations themselves through averaging barycenter-shifted residuals. We have demonstrated 5 ms −1 precision over oneyear timescales for the M4 dwarf Barnard's Star and K dwarf 61 Cygni A, and 3 ms −1 over a month for the M2 dwarf GJ 15 A. This work demonstrates the potential for iSHELL to determine dynamical masses for candidate exoplanets discovered with the NASA TESS mission, and to search for exoplanets orbiting moderately active and/or young K & M dwarfs.

show abstract

Design and Construction of Absorption Cells for Precision Radial Velocities in theKBand Using Methane Isotopologues

Cited by 41 publications

References 36 publications

A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

A Search for Giant Planet Companions to T Tauri Stars

Precise Radial Velocities of Cool Low-mass Stars with iSHELL

Contact Info

Product

Resources

About