MuSCAT Intrument for Characterizing Exoplanet Atmosphere's Ready, Tested on Gliese 436b

MuSCAT: a multicolor simultaneous camera for studying atmospheres of transiting exoplanets

Authors:

Narita et al

Abstract:

We report a development of a multi-color simultaneous camera for the 188cm telescope at Okayama Astrophysical Observatory in Japan. The instrument, named MuSCAT, has a capability of 3-color simultaneous imaging in optical wavelength where CCDs are sensitive. MuSCAT is equipped with three 1024x1024 pixel CCDs, which can be controlled independently. The three CCDs detect lights in g′2 (400--550 nm), r′2 (550--700 nm), and zs,2 (820--920 nm) bands using Astrodon Photometrics Generation 2 Sloan filters. The field of view of MuSCAT is 6.1x6.1 arcmin2 with the pixel scale of 0.358 arcsec per pixel. The principal purpose of MuSCAT is to perform high precision multi-color transit photometry. For the purpose, MuSCAT has a capability of self autoguiding which enables to fix positions of stellar images within ~1 pix. We demonstrate relative photometric precisions of 0.101%, 0.074%, and 0.076% in g′2, r′2, and zs,2 bands, respectively, for GJ436 (magnitudes in g′=11.81, r′=10.08, and z′=8.66) with 30 s exposures. The achieved precisions meet our objective, and the instrument is ready for operation.

Improving Planet-Finding Spectrometers

Improving Planet-Finding Spectrometers

Author:

Crepp

Abstract:

Like the miniaturization of modern computers, next-generation radial velocity instruments will be significantly smaller and more powerful than their predecessors.

Simulating the Next Gen Exoplanet Detection Instrumentation of the Subaru Telescope

CHARIS Science: Performance Simulations for the Subaru Telescope's Third-Generation of Exoplanet Imaging Instrumentation

Authors:

Brandt et al

Abstract:

We describe the expected scientific capabilities of CHARIS, a high-contrast integral-field spectrograph (IFS) currently under construction for the Subaru telescope. CHARIS is part of a new generation of instruments, enabled by extreme adaptive optics (AO) systems (including SCExAO at Subaru), that promise greatly improved contrasts at small angular separation thanks to their ability to use spectral information to distinguish planets from quasistatic speckles in the stellar point-spread function (PSF). CHARIS is similar in concept to GPI and SPHERE, on Gemini South and the Very Large Telescope, respectively, but will be unique in its ability to simultaneously cover the entire near-infrared J, H, and K bands with a low-resolution mode. This extraordinarily broad wavelength coverage will enable spectral differential imaging down to angular separations of a few λ/D, corresponding to ∼0.″1. SCExAO will also offer contrast approaching 10−5 at similar separations, ∼0.″1--0.″2. The discovery yield of a CHARIS survey will depend on the exoplanet distribution function at around 10 AU. If the distribution of planets discovered by radial velocity surveys extends unchanged to ∼20 AU, observations of ∼200 mostly young, nearby stars targeted by existing high-contrast instruments might find ∼1--3 planets. Carefully optimizing the target sample could improve this yield by a factor of a few, while an upturn in frequency at a few AU could also increase the number of detections. CHARIS, with a higher spectral resolution mode of R∼75, will also be among the best instruments to characterize planets and brown dwarfs like HR 8799 cde and κ And b.

Instrumentation for Detecting Exoplanets

Instrumentation for the detection and characterization of exoplanets

Authors:

Pepe et al

Abstract:

In no other field of astrophysics has the impact of new instrumentation been as substantial as in the domain of exoplanets. Before 1995 our knowledge about exoplanets was mainly based on philosophical and theoretical considerations. The following years have been marked, instead, by surprising discoveries made possible by high-precision instruments. More recently the availability of new techniques moved the focus from detection to the characterization of exoplanets. Next-generation facilities will produce even more complementary data that will lead to a comprehensive view of exoplanet characteristics and, by comparison with theoretical models, to a better understanding of planet formation.

Segmented Pupil Experiment for Exoplanet Detection

SPEED: the Segmented Pupil Experiment for Exoplanet Detection

Authors:

Patrice et al

Abstract:

Searching for nearby exoplanets with direct imaging is one of the major scientific drivers for both space and ground-based programs. While the second generation of dedicated high-contrast instruments on 8-m class telescopes is about to greatly expand the sample of directly imaged planets, exploring the planetary parameter space to hitherto-unseen regions ideally down to Terrestrial planets is a major technological challenge for the forthcoming decades. This requires increasing spatial resolution and significantly improving high contrast imaging capabilities at close angular separations. Segmented telescopes offer a practical path toward dramatically enlarging telescope diameter from the ground (ELTs), or achieving optimal diameter in space. However, translating current technological advances in the domain of high-contrast imaging for monolithic apertures to the case of segmented apertures is far from trivial. SPEED (the segmented pupil experiment for exoplanet detection) is a new instrumental facility in development at the Lagrange laboratory for enabling strategies and technologies for high-contrast instrumentation with segmented telescopes. SPEED combines wavefront control including precision segment phasing architectures, wavefront shaping using two sequential high order deformable mirrors for both phase and amplitude control, and advanced coronagraphy struggled to very close angular separations (PIAACMC). SPEED represents significant investments and technology developments towards the ELT area and future spatial missions, and will offer an ideal cocoon to pave the road of technological progress in both phasing and high-contrast domains with complex/irregular apertures. In this paper, we describe the overall design and philosophy of the SPEED bench.

A new EMCCD for Space-based High Contrast Imaging Spectroscopy for WFIRST

Characterization of a photon counting EMCCD for space-based high contrast imaging spectroscopy of extrasolar planets

Authors:

Wilkins et al

Abstract:

We present the progress of characterization of a low-noise, photon counting Electron Multiplying Charged Coupled Device (EMCCD) operating in optical wavelengths and demonstrate possible solutions to the problems of Clock-Induced Charge (CIC) and other trapped charge through sub-bandgap illumination. Such a detector will be vital to the feasibility of future space-based direct imaging and spectroscopy missions for exoplanet characterization, and is scheduled to fly on-board the AFTA-WFIRST mission. The 512×512 EMCCD is an e2v detector housed and clocked by a N\"uv\"u Cameras controller. Through a multiplication gain register, this detector produces as many as 5000 electrons for a single, incident-photon-induced photoelectron produced in the detector, enabling single photon counting operation with read noise and dark current orders of magnitude below that of standard CCDs. With the extremely high contrasts (Earth-to-Sun flux ratio is ∼ 10−10) and extremely faint targets (an Earth analog would measure 28th - 30th magnitude or fainter), a photon-counting EMCCD is absolutely necessary to measure the signatures of habitability on an Earth-like exoplanet within the timescale of a mission's lifetime, and we discuss the concept of operations for an EMCCD making such measurements.

Can we Detect Hydrogen Coronae in Exoplanet Atmospheres?

Can hydrogen coronae be inferred around a CO2-dominated exoplanetary atmosphere?

Authors:

Bernard et al

Abstract:

To date, almost 20% of the known exoplanets are in the Earth/super-Earth mass regime, and more have to be confirmed, as they represent about 40% of the Kepler candidates. Some of these planets like the Kepler-11 system exhibit very low densities, which can be explained by a high content in water (“waterworlds”) or a large hydrogen/helium atmosphere. Recent theoretical work has been done to explain how a low mass planet could sustain such an atmosphere for several Gyr. On the other hand, some authors have proposed methods based on transit absorption spectroscopy to detect and characterize these possible atmospheres. In this paper, we explore the possibility of inferring the presence of an atomic hydrogen corona by looking at its influence on the thermospheric emissions of a lower CO2 atmosphere. Two emission lines are studied in details, namely the O(1S − 1D ) “green-line” at 557 nm and the View the MathML sourceCO2+(View the MathML sourceB2Σu+-X2Πg) UV-doublet around 289 nm. We use a 1D transport code coupled to a radiative transfer model to calculate the emissions of the planet and the contrast with its parent star at the two emission lines. We find that in the case of a telluric planet at 1 AU from a G-type star or at 0.03 AU from an active M dwarf, the contrasts between the star and the planet are too low to be observed with current or planned instruments.