The Planet as Exoplanet Analog Spectrograph (PEAS): Design and First-Light
Emily C. Martin, Andrew J. Skemer, Matthew V. Radovan, Steven L. Allen, David Black, William T. S. Deich, Jonathan J. Fortney, Gabriel Kruglikov, Nicholas MacDo… 展开作者
Emily C. Martin, Andrew J. Skemer, Matthew V. Radovan, Steven L. Allen, David Black, William T. S. Deich, Jonathan J. Fortney, Gabriel Kruglikov, Nicholas MacDonald, David Marques, Evan C. Morris, Andrew C. Phillips, Dale Sandford, Julissa Villalobos Valencia, Jason J. Wang, Pavl Zachary
Exoplanets are abundant in our galaxy and yet characterizing them remains a technical challenge. Solar System planets provide an opportunity to test the practical limitations of exoplanet observations with high signal-to-noise data that we cannot access for exoplanets. However, data on Solar System planets differ from exoplanets in that Solar System planets are spatially resolved while exoplanets are unresolved point-sources. We present a novel instrument designed to observe Solar System planets as though they are exoplanets, the Planet as Exoplanet Analog Spectrograph (PEAS). PEAS consists of a dedicated 0.5-m telescope and off-the-shelf optics, located at Lick Observatory. PEAS uses an integrating sphere to disk-integrate light from the Solar System planets, producing spatially mixed light more similar to the spectra we can obtain from exoplanets. This paper describes the general system design and early results of the PEAS instrument.
Understanding the atmospheres of exoplanets is a milestone to decipher their formation history and potential habitability. High-contrast imaging and spectroscopy of exoplanets is the major pathway towards the goal. Directly imaging of an exoplanet requires high spatial resolution. Interferometry has proven to be an effective way of improving spatial resolution. However, means of combining interferometry, high-contrast imaging, and high-resolution spectroscopy have been rarely explored. To fill in the gap, we present the dual-aperture fiber nuller (FN) for current-generation 8-10 meter telescop…
The Near-Inrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST) is a very versatile instrument, offering multiobject and integral field spectroscopy with varying spectral resolution ($\sim$30 to $\sim$3000) over a wide wavelength range from 0.6 to 5.3 micron, enabling scientists to study many science themes ranging from the first galaxies to bodies in our own Solar System. In addition to its integral field unit and support for multiobject spectroscopy, NIRSpec features several fixed slits and a wide aperture specifically designed to enable high precision time-series and transi…
Integral field spectrographs are an important technology for exoplanet imaging, due to their ability to take spectra in a high-contrast environment, and improve planet detection sensitivity through spectral differential imaging. ALES is the first integral field spectrograph capable of imaging exoplanets from 3-5$μ$m, and will extend our ability to characterize self-luminous exoplanets into a wavelength range where they peak in brightness. ALES is installed inside LBTI/LMIRcam on the Large Binocular Telescope, taking advantage of existing AO systems, camera optics, and a HAWAII-2RG detector. Th…
Investigating the atmospheres of rocky exoplanets is key to performing comparative planetology between these worlds and the terrestrial planets that reside in the inner solar system. Terrestrial exoplanet atmospheres exhibit weak signals, and attempting to detect them pushes at the boundaries of what is possible for current instrumentation. We focus on the habitable-zone terrestrial exoplanet LHS 1140b. Given its 25-day orbital period and 2 hr transit duration, capturing transits of LHS 1140b is challenging. We observed two transits of this object, approximately 1 yr apart, which yielded four …
Ground-based, high-resolution spectrographs are providing us with an unprecedented view of the dynamics and chemistry of the atmospheres of planets outside the Solar System. While there is a large number of stable and precise high-resolution spectrographs on modest-size telescopes, it is the spectrographs at observatories with apertures larger than 3.5 metres that dominate the atmospheric follow-up of exoplanets. In this work, we explore the potential of characterising exoplanetary atmospheres with FIES, a high-resolution spectrograph at the 2.56 metre Nordic Optical Telescope. We observed two…
The ESPRESSO spectrograph at ESO's Very Large Telescope (VLT) has, since it began science operations in October 2018, revolutionised exoplanet science. The combination of the large VLT mirrors and the high resolution and stability of the spectrograph is enabling the detection of small, low-mass planets as well as detailed studies of the planets' atmospheres. In this article, we present a brief overview of the first results from ESPRESSO and a hopeful glimpse towards the ultimate goal of reaching the radial velocity precision of 10 cm/s needed to detect an Earth-like planet.
Photonic spectrographs offer a highly miniaturized, flexible, and stable on-chip solution for astronomical spectroscopy and can be used for various science cases such as determining the atmospheric composition of exoplanets to understand their habitability, formation, and evolution. Arrayed Waveguide Gratings (AWGs) have shown the best promise to be used as an astrophotonic spectrograph. We developed a publically-available tool to conduct a preliminary examination of the capability of the AWGs in spectrally resolving exoplanet atmospheres. We derived the Line-Spread-Function (LSF) as a functio…
ANDES, the high-resolution spectrograph of the ELT: simulated performance of the CORO module and overview of the high-contrast capabilities for exoplanet observations
Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange（蔚蓝海岸大学，蔚蓝海岸天文台，法国国家科学研究中心，拉格朗日实验室）；Lund Observatory, Division of Astrophysics, Department of Physics, Lund University（隆德大学，物理系，天体物理学部，隆德天文台）；INAF - Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所，阿切特里天文台）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；Instituto de Astronomía, Univ. Nacional Autónoma de México（墨西哥国立自治大学，天文研究所）；LUPM, Université de Montpellier, CNRS（蒙彼利埃大学，法国国家科学研究中心，LUPM实验室）；Université Grenoble Alpes, CNRS, IPAG（格勒诺布尔阿尔卑斯大学，法国国家科学研究中心，IPAG实验室）；INAF - Osservatorio Astrofisico di Brera（意大利国家天体物理研究所，布雷拉天文台）；Aix Marseille Université, CNRS, CNES, LAM（艾克斯马赛大学，法国国家科学研究中心，法国国家空间研究中心，LAM实验室）；INAF - Osservatorio Astronomico di Trieste（意大利国家天体物理研究所，的里雅斯特天文台）
介绍了 ANDES 高分辨率光谱仪日冕仪模块，其能结合高对比度成像与高色散光谱学研究系外行星特性，详细阐述设计、特征及模拟性能，展示初步模拟结果并讨论表征操作，以评估其对系外行星大气特征的探测能力。
Fulfilling the goals of space-based exoplanetary transit surveys, like Kepler and TESS, is impossible without ground-based spectroscopic follow-up. In particular, the first-step vetting of candidates could easily necessitate several hundreds of hours of telescope time -- an area where 2-m class telescopes can play a crucial role. Here, we describe the results from the science verification of the Ondřejov Echelle Spectrograph (OES) installed on the 2-m Perek telescope. We discuss the performance of the instrument as well as its suitability for the study of exoplanetary candidates from space-bas…
New generation exoplanet imagers on large ground-based telescopes are highly optimised for the detection of young giant exoplanets in the near-infrared, but they are intrinsically limited for their characterisation by the low spectral resolution of their integral field spectrographs ($R<100$). High-dispersion spectroscopy at $R \gg 10^4$ would be a powerful tool for the characterisation of these planets, but there is currently no high-resolution spectrograph with extreme adaptive optics and coronagraphy that would enable such characterisation. With project HiRISE we propose to use fiber coupli…
One limitation in characterizing exoplanet candidates is the availability of infrared, high-resolution spectrographs. An important factor in the scarcity of high precision IR spectrographs is the high cost of these instruments. We present a new optical design, which leads to a cost-effective solution. Our instrument is a high-resolution (R=60,000) infrared spectrograph with a R6 Echelle grating and an image slicer. We compare the best possible performance of quasi-Littrow and White Pupil setups, and prefer the latter because it achieves higher image quality. The instrument is proposed for the …
We introduce the RISTRETTO instrument for ESO VLT, an evolution from the original idea of connecting the SPHERE high-contrast facility to the ESPRESSO spectrograph (Lovis et al 2017). RISTRETTO is an independent, AO-fed spectrograph proposed as a visitor instrument, with the goal of detecting nearby exoplanets in reflected light for the first time. RISTRETTO aims at characterizing the atmospheres of Proxima b and several other exoplanets using the technique of high-contrast, high-resolution spectroscopy. The instrument is composed of two parts: a front-end to be installed on VLT UT4 providing …
HISPEC (High-resolution Infrared Spectrograph for Exoplanet Characterization) is a proposed diffraction-limited spectrograph for the W.M. Keck Observatory, and a pathfinder for the MODHIS facility project (Multi-Object Diffraction-limited High-resolution Infrared Spectrograph) on the Thirty Meter Telescope. HISPEC/MODHIS builds on diffraction-limited spectrograph designs which rely on adaptively corrected single-mode fiber feeds. Seeing-limited high-resolution spectrographs, by virtue of the conservation of beam etendue, grow in volume following a D^3 power law (D is the telescope diameter), a…
Within the ESPRESSO project a new flexible data reduction library is being built. ESPRESSO, the Echelle SPectrograph for Rocky Exoplanets and Stable Spectral Observations is a fiber-fed, high-resolution, cross-dispersed echelle spectrograph. One of its main scientific goals is to search for terrestrial exoplanets using the radial velocity technique. A dedicated pipeline is being developed. It is designed to be able to reduce data from different similar spectrographs: not only ESPRESSO, but also HARPS, HARPS-N and possibly others. Instrument specifics are configurable through an input static co…
The Prototype Imaging Spectrograph for Coronagraphic Exoplanet Studies (PISCES) is a high contrast integral field spectrograph (IFS) whose design was driven by WFIRST coronagraph instrument requirements. We present commissioning and operational results using PISCES as a camera on the High Contrast Imaging Testbed at JPL. PISCES has demonstrated ability to achieve high contrast spectral retrieval with flight-like data reduction and analysis techniques.
High-precision spectrographs play a key role in exoplanet searches and Doppler asteroseismology using the radial velocity technique. The 1 m/s level of precision requires very high stability and uniformity of the illumination of the spectrograph. In fiber-fed spectrographs such as SOPHIE, the fiber-link scrambling properties are one of the main conditions for high precision. To significantly improve the radial velocity precision of the SOPHIE spectrograph, which was limited to 5-6 m/s, we implemented a piece of octagonal-section fiber in the fiber link. We present here the scientific validatio…
High-resolution spectroscopy has proven to be a powerful avenue for atmospheric remote sensing of exoplanets. Recently, ESO commissioned the CRIRES+ high-resolution infrared spectrograph at VLT. CRIRES+ is a cross-dispersed spectrograph with high throughput and wide wavelength coverage across the near-infrared (0.95-5.3 $μ$m), designed to be particularly suited for atmospheric characterisation of exoplanets. In this work, we report early insights into the performance of CRIRES+ for exoplanet spectroscopy and conduct a detailed assessment of the data reduction procedure. Because of the novelty …
The World Space Observatory for Ultraviolet (WSO-UV) is an orbital optical telescope with a 1.7 m-diameter primary mirror currently under development. The WSO-UV is aimed to operate in the 115-310 nm UV spectral range. Its two major science instruments are UV spectrographs and a UV imaging field camera with filter wheels. The WSO-UV project is currently in the implementation phase, with a tentative launch date in 2023. Recently, two additional instruments devoted to exoplanets have been proposed for WSO-UV, which are the focus of this paper. UVSPEX, a UV-Spectrograph for Exoplanets, aims to de…
We present recent results obtained with the VLT/MUSE Integral Field Spectrograph fed by the 4LGSF and its laser tomography adaptive optics module GALACSI. While this so-called narrow-field mode of MUSE was not designed to perform directly imaging of exoplanets and outflows, we show that it can be a game changer to detect and characterize young exoplanets with a prominent emission lines (i.e Hα, tracer of accretion), at moderate contrasts. These performances are achieved thanks to the combo of a near-diffraction limited PSF and a medium resolution spectrograph and a cross-correlation approach i…
Exoplanet science is booming. In 20 years our knowledge has expanded considerably, from the first discovery of a Hot Jupiter, to the detection of a large population of Neptunes and super-Earths, to the first steps toward the characterization of exoplanet atmospheres. Between today and 2025, the field will evolve at an even faster pace with the advent of several space-based transit search missions, ground-based spectrographs, high-contrast imaging facilities, and the James Webb Space Telescope. Especially the ESA M-class PLATO mission will be a game changer in the field. From 2024 onwards, PLAT…
We outline the important role that ground-based, Doppler monitoring of exoplanetary systems will play in advancing our theories of planet formation and dynamical evolution. A census of planetary systems requires a well designed survey to be executed over the course of a decade or longer. A coordinated survey to monitor several thousand targets each at ~1000 epochs (~3-5 million new observations) will require roughly 40 dedicated spectrographs. We advocate for improvements in data management, data sharing, analysis techniques, and software testing, as well as possible changes to the funding str…
We summarize the red channel (2-5 micron) of the Planetary Systems Imager (PSI), a proposed second-generation instrument for the TMT. Cold exoplanets emit the majority of their light in the thermal infrared, which means these exoplanets can be detected at a more modest contrast than at other wavelengths. PSI-Red will be able to detect and characterize a wide variety of exoplanets, including radial-velocity planets on wide orbits, accreting protoplanets in nearby star-forming regions, and reflected-light planets around the nearest stars. PSI-Red will feature an imager, a low-resolution lenslet …
We present end-to-end simulations of SCALES, the third generation thermal-infrared diffraction limited imager and low/med-resolution integral field spectrograph (IFS) being designed for Keck. The 2-5 micron sensitivity of SCALES enables detection and characterization of a wide variety of exoplanets, including exoplanets detected through long-baseline astrometry, radial-velocity planets on wide orbits, accreting protoplanets in nearby star-forming regions, and reflected-light planets around the nearest stars. The simulation goal is to generate high-fidelity mock data to assess the scientific ca…
Direct imaging characterization of extrasolar planets is often done at low spectral resolution. We model the spectrograph for the Gemini Planet Imager upgrade (GPI 2.0) and assess the instrument's potential for allowing observers to constrain exoplanet properties through analysis of near-infrared spectra. We simulated noisy observations followed by calculations of posterior distributions from maximum likelihood comparison with the Sonora 2018 model grid. Preliminary results suggest that GPI 2.0 should allow observers to constrain temperature with sufficient accuracy, but gravity remains largel…
Recent developments in high-contrast imaging techniques now make possible both imaging and spectroscopy of planets around nearby stars. We present the conceptual design of the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS), a lenslet-based, cryogenic integral field spectrograph (IFS) for imaging exoplanets on the Subaru telescope. The IFS will provide spectral information for 140x140 spatial elements over a 1.75 arcsecs x 1.75 arcsecs field of view (FOV). CHARIS will operate in the near infrared (lambda = 0.9 - 2.5 microns) and provide a spectral resolution of R = 14, 33, …
KMOS (K-Band Multi Object Spectrograph) is a novel integral field spectrograph installed in the VLT's ANTU unit. The instrument offers an ability to observe 24 2.8"$\times$2.8" sub-fields positionable within a 7.2' patrol field, each sub-field producing a spectrum with a 14$\times$14-pixel spatial resolution. The main science drivers for KMOS are the study of galaxies, star formation, and molecular clouds, but its ability to simultaneously measure spectra of multiple stars makes KMOS an interesting instrument for exoplanet atmosphere characterization via transmission spectroscopy. We set to te…
Short-orbit gas giant planet formation/evolution mechanisms are still not well understood. One promising pathway to discriminate between mechanisms is to constrain the occurrence rate of these peculiar exoplanets at the earliest stage of the system's life. However, a major limitation when studying newly born stars is stellar activity. This cocktail of phenomena triggered by fast rotation, strong magnetic fields and complex internal dynamics, especially present in very young stars, compromises our ability to detect exoplanets. In this paper, we investigated the limitations of such detections in…
Precise Doppler radial-velocity (RV) instruments will continue to play an essential role in advancing our holistic understanding of exoplanetary systems. The combination of orbital parameters from transit surveys and follow-up RV measurements is vital to unlock mass and density estimates of detected planets, giving us insight into their environment and structure. However, the exoplanet field is reaching a critical juncture: the measurement sensitivity of existing radial-velocity instruments is becoming the limiting factor in further increasing our knowledge. Without improvement in delivered RV…
The MINiature Exoplanet Radial Velocity Array (MINERVA) is a dedicated observatory of four 0.7m robotic telescopes fiber-fed to a KiwiSpec spectrograph. The MINERVA mission is to discover super-Earths in the habitable zones of nearby stars. This can be accomplished with MINERVA's unique combination of high precision and high cadence over long time periods. In this work, we detail changes to the MINERVA facility that have occurred since our previous paper. We then describe MINERVA's robotic control software, the process by which we perform 1D spectral extraction, and our forward modeling Dopple…
High-contrast imaging techniques now make possible both imaging and spectroscopy of planets around nearby stars. We present the optical design for the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS), a lenslet-based, cryogenic integral field spectrograph (IFS) for imaging exoplanets on the Subaru telescope. The IFS will provide spectral information for 138x138 spatial elements over a 2.07 arcsec x 2.07 arcsec field of view (FOV). CHARIS will operate in the near infrared (lambda = 1.15 - 2.5 microns) and will feature two spectral resolution modes of R = 18 (low-res mode) and…
The direct detection of exoplanets with high-contrast instruments can be boosted with high spectral resolution. For integral field spectrographs yielding hyperspectral data, this means that the field of view consists of diffracted starlight spectra and a spatially localized planet. Analysis usually relies on cross-correlation with theoretical spectra. In a purely blind-search context, this supervised strategy can be biased with model mismatch and/or be computationally inefficient. Using an approach that is inspired by the remote-sensing community, we aim to propose an alternative to cross-corr…
Detection of weak radial velocity shifts of host stars induced by orbiting planets is an important technique for discovering and characterizing planets beyond our solar system. Optical frequency combs enable calibration of stellar radial velocity shifts at levels required for detection of Earth analogs. A new chip-based device, the Kerr soliton microcomb, has properties ideal for ubiquitous application outside the lab and even in future space-borne instruments. Moreover, microcomb spectra are ideally suited for astronomical spectrograph calibration and eliminate filtering steps required by con…
Observations of circumstellar environments to look for the direct signal of exoplanets and the scattered light from disks has significant instrumental implications. In the past 15 years, major developments in adaptive optics, coronagraphy, optical manufacturing, wavefront sensing and data processing, together with a consistent global system analysis have enabled a new generation of high-contrast imagers and spectrographs on large ground-based telescopes with much better performance. One of the most productive is the Spectro-Polarimetic High contrast imager for Exoplanets REsearch (SPHERE) desi…
Vortex fiber nulling is a method for spectroscopically characterizing exoplanets at small angular separations, $\lesssimλ/D$, from their host star. The starlight is suppressed by creating an optical vortex in the system point spread function, which prevents the stellar field from coupling into the fundamental mode of a single-mode optical fiber. Light from the planet, on the other hand, couples into the fiber and is routed to a spectrograph. Using a prototype vortex fiber nuller (VFN) designed for monochromatic light, we demonstrate coupling fractions of $6\times10^{-5}$ and $>0.1$ for the sta…
We search for transiting exoplanets around the star $β$ Pictoris using high resolution spectroscopy and Doppler imaging that removes the need for standard star observations. These data were obtained on the VLT with UVES during the course of an observing campaign throughout 2017 that monitored the Hill sphere transit of the exoplanet $β$ Pictoris b. We utilize line profile tomography as a method for the discovery of transiting exoplanets. By measuring the exoplanet distortion of the stellar line profile, we remove the need for reference star measurements. We demonstrate the method with white no…
The RISTRETTO project is aiming to build an instrument that will detect the reflected light from close-by exoplanet. It is a two stage instrument: An extreme AO system in the visible, followed by a seven spaxel single mode High resolution Spectrograph. In this paper we present the design of this spectrograph: a classical echelle spectrograph fed with single mode fibers. Standard single mode fibers have been chosen and are forming a long tilted slit in order to have the right order spacing on the detector. The instrument will be under vacuum and thermally controlled in order to make it stable.
Although there exists a large sample of known exoplanets, little spectroscopic data exists that can be used to study their global atmospheric properties. This deficiency can be addressed by performing phase-resolved spectroscopy -- continuous spectroscopic observations of a planet's entire orbit about its host star -- of transiting exoplanets. Planets with characteristics suitable for atmospheric characterization have orbits of several days, thus phase curve observations are highly resource intensive, especially for shared use facilities. In this work, we show that an infrared spectrograph ope…
