HISPEC is a new, high-resolution near-infrared spectrograph being designed for the W.M. Keck II telescope. By offering single-shot, R 100,000 spectroscopy between 0.98 – 2.5 μm, HISPEC will enable spectroscopy of transiting and non-transiting exoplanets in close orbits, direct high-contrast detection and spectroscopy of spatially separated substellar companions, and exoplanet dynamical mass and orbit measurements using precision radial velocity monitoring calibrated with a suite of state-of-the-art absolute and relative wavelength references. MODHIS is the counterpart to HISPEC for the Thirty Meter Telescope and is being developed in parallel with similar scientific goals. In this proceeding, we provide a brief overview of the current design of both instruments, and the requirements for the two spectrographs as guided by the scientific goals for each. We then outline the current science case for HISPEC and MODHIS, with focuses on the science enabled for exoplanet discovery and characterization. We also provide updated sensitivity curves for both instruments, in terms of both signal-to-noise ratio and predicted radial velocity precision.
The PAlomar Radial Velocity Instrument (PARVI) is a diffraction-limited, high-resolution spectrograph connected by single-mode fiber to the 200 inch Hale telescope at Palomar Observatory. Here, we present on-sky results for HD 189733 obtained during PARVI’s commissioning phase. We first describe the implementation of our spectral extraction and radial velocity (RV) generation codes. Through RV monitoring, we detect the Rossiter–Mclaughlin signal of the transiting planet HD 189733 b. We further detect the presence of water and carbon monoxide in the atmosphere of HD 189733 b via transmission spectroscopy. This work demonstrates PARVI’s high-resolution spectral capabilities at H band and current intra-night Doppler stability of ∼4 to 10 m s − 1 on an early K dwarf. Finally, we discuss the limitations to this work and ongoing efforts to characterize and improve the Doppler performance of PARVI to the design goal of ∼1 m s − 1 for late-type stars.
KEYWORDS: Sensors, Calibration, Image processing, Spectrographs, Single mode fibers, Point spread functions, Signal to noise ratio, Data acquisition, Absorption, Fiber science
We describe the data reduction pipeline (DRP) for the Palomar Radial Velocity instrument (PARVI). PARVI is a fiber-fed, high-resolution J and H band spectrometer that targets cool, low-mass stars for the purpose of measuring precise radial velocities to determine companion masses. The spectrograph is fed with four single-mode fibers and records science and laser frequency comb wavelength reference spectra simultaneously. We describe and report on the performances of the data reduction process from two-dimensional image acquisition to reduced, wavelength-calibrated one-dimensional spectra. At this time, a single wavelength solution provides a precision of 3.3 m / s.
KEYWORDS: Near infrared, Stars, Single mode fibers, Motion measurement, Frequency combs, Telescopes, Spectroscopy, Spectrographs, Spectral resolution, Signal detection
The field of precision radial velocities (PRVs) aims to detect radial velocity (RV) signals on the order of 1 m/s. The motivation for the push into PRV is to detect the reflex motion of stars induced by Earth-sized orbiting planets. Measuring PRVs in the near-infrared (NIR) provides a number of advantages over optical, such as reduced noise from stellar jitter, and wealth of RV information encoded in the NIR absorption features of cool, low-mass stars. The Palomar Radial Velocity Instrument (PARVI) implements three key strategies to achieve 1 m/s RV precision in the NIR: single-mode fiber (SMF) feeds, thermo-mechanical stabilization of the spectrograph, and a line-referenced, electro-optical modulation frequency comb (LR-EOFC). PARVI is a J & H band (1145-1766 nm) echelle spectrometer with spectral resolution 87,000–121,000. It was installed at the Hale 200" telescope summer 2019, and since then has undergone multiple hardware upgrades to maximize stability. Using the laser frequency comb (LFC) as a light source, we measure a science channel to reference channel stability of 0.001 pixels over the timespan of a single observing night. This measurement includes the motion of 2790 LFC lines over 17 spectral orders in the H band, and corresponds to a radial velocity precision of approximately 1 m/s at the LFC pump line (lambda_p = 1560 nm).
KEYWORDS: Sensors, Signal to noise ratio, Stars, Cameras, Cadmium sulfide, Spectrographs, Single mode fibers, Adaptive optics, Signal detection, Telescopes
A wave of precision radial velocity (RV) instruments will open the door to exploring the populations of companions of low-mass stars. The Palomar Radial Velocity Instrument (PARVI) will be optimized to detect RV signals of cool K and M stars with an instrument precision floor of 30 cm / s. PARVI will operate in the λ = 1.2- to 1.8-μm-wavelength range with a spectral resolution of λ / Δλ ∼ 100,000. It will operate on the Palomar 5.1-m Hale telescope and use Palomar’s PALM-3000 adaptive optics system, single-mode fibers, and an H-band laser frequency comb to probe and characterize the population of planets around cool, red stars. We describe the performance of the PARVI guide camera: a C-RED 2 from First Light Advanced Imagery. The C-RED 2 will be used in a tip-tilt loop, which requires fast readout at low noise levels to eliminate any residual guide errors and ensure the target starlight stays centered on the fiber. At −40 ° C and a frame rate of 400 frames per second in nondestructive read mode, the C-RED 2 has a combined dark and background current of 493 e − / s. Using up-the-ramp sampling, we are able to reduce the read noise to 21.2 e − . With the C-RED 2, PARVI will be able to guide using targets as faint as 14.6 H magnitude.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.