scholarly journals Molecular cross-sections for high-resolution spectroscopy of super-Earths, warm Neptunes, and hot Jupiters

2020 ◽  
Vol 495 (1) ◽  
pp. 224-237 ◽  
Author(s):  
Siddharth Gandhi ◽  
Matteo Brogi ◽  
Sergei N Yurchenko ◽  
Jonathan Tennyson ◽  
Phillip A Coles ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Sections ◽  
Cross Correlation ◽  
High Resolution Spectroscopy ◽  
High Signal ◽  
Pressure Broadening ◽  
Spectral Signatures ◽  
Hot Jupiters ◽  
Wide Range ◽  
Infrared Spectral

ABSTRACT High-resolution spectroscopy (HRS) has been used to detect a number of species in the atmospheres of hot Jupiters. Key to such detections is accurately and precisely modelled spectra for cross-correlation against the R ≳ 20 000 observations. There is a need for the latest generation of opacities which form the basis for high signal-to-noise detections using such spectra. In this study we present and make publicly available cross-sections for six molecular species, H2O, CO, HCN, CH4, NH3, and CO2 using the latest line lists most suitable for low- and high-resolution spectroscopy. We focus on the infrared (0.95–5 μm) and between 500 and 1500 K where these species have strong spectral signatures. We generate these cross-sections on a grid of pressures and temperatures typical for the photospheres of super-Earth, warm Neptunes, and hot Jupiters using the latest H2 and He pressure broadening. We highlight the most prominent infrared spectral features by modelling three representative exoplanets, GJ 1214 b, GJ 3470 b, and HD 189733 b, which encompass a wide range in temperature, mass, and radii. In addition, we verify the line lists for H2O, CO, and HCN with previous high-resolution observations of hot Jupiters. However, we are unable to detect CH4 with our new cross-sections from HRS observations of HD 102195 b. These high-accuracy opacities are critical for atmospheric detections with HRS and will be continually updated as new data become available.

Studies of the atmosphere of ultra-hot Jupiter TOI-1431b/MASCARA-5b

2021 ◽  
Author(s):  
Monika Stangret ◽  
Enric Palle ◽  
Núria Casasayas-Barris ◽  
Mahmoud Oshagh
Keyword(s):  
High Resolution ◽  
Cross Correlation ◽  
Giant Planets ◽  
High Resolution Spectroscopy ◽  
Polar Orbit ◽  
Hot Jupiters ◽  
History Of ◽  
F Stars ◽  
Suitable Object ◽  
Hot Jupiter

<p>Ultra-hot Jupiters are defined as giant planets with equilibrium temperatures larger than 2000 K. Most of them are found orbiting bright A-F stars, making them extremely suitable object to study their atmospheres using high-resolution spectroscopy.</p> <p>TOI-1431b, also known as MASCARA-5b, a newly discovered planet with the temperature of 2375 K is a prefect example of ultra-hot Jupiter. We studied this object using three transit observations obtained with high-resolution spectrographs HARPS-N and EXPRES. Analysis of Rossiter-McLaughlin effect shows that the planet is in the polar orbit, which speaks about an interesting dynamical history, and perhaps indicating the presence of more than one planet in the early history of this system. Applying the cross-correlation and transmission spectroscopy method, we find no evidence of atoms and molecules in this planet. There results are at odds with the other studies of similar UHJs orbiting bright stars, where various species have been found.</p>

scholarly journals Remote sensing of exoplanetary atmospheres with ground-based high-resolution near-infrared spectroscopy

2019 ◽  
Vol 629 ◽  
pp. A109 ◽  
Author(s):  
D. Shulyak ◽  
M. Rengel ◽  
A. Reiners ◽  
U. Seemann ◽  
F. Yan
Keyword(s):  
Infrared Spectroscopy ◽  
Temperature Distribution ◽  
High Resolution ◽  
Near Infrared Spectroscopy ◽  
Atmospheric Chemistry ◽  
Near Infrared ◽  
Optimal Estimation ◽  
High Resolution Spectroscopy ◽  
High Signal ◽  
Wide Range

Context. Thanks to the advances in modern instrumentation we have learned about many exoplanets that span a wide range of masses and composition. Studying their atmospheres provides insight into planetary origin, evolution, dynamics, and habitability. Present and future observing facilities will address these important topics in great detail by using more precise observations, high-resolution spectroscopy, and improved analysis methods. Aims. We investigate the feasibility of retrieving the vertical temperature distribution and molecular number densities from expected exoplanet spectra in the near-infrared. We use the test case of the CRIRES+ instrument at the Very Large Telescope which will operate in the near-infrared between 1 and 5 μm and resolving powers of R = 100 000 and R = 50 000. We also determine the optimal wavelength coverage and observational strategies for increasing accuracy in the retrievals. Methods. We used the optimal estimation approach to retrieve the atmospheric parameters from the simulated emission observations of the hot Jupiter HD 189733b. The radiative transfer forward model is calculated using a public version of the τ-REx software package. Results. Our simulations show that we can retrieve accurate temperature distribution in a very wide range of atmospheric pressures between 1 bar and 10−6 bar depending on the chosen spectral region. Retrieving molecular mixing ratios is very challenging, but a simultaneous observations in two separate infrared regions around 1.6 and 2.3 μm helps to obtain accurate estimates; the exoplanetary spectra must be of relatively high signal-to-noise ratio S∕N ≥ 10, while the temperature can already be derived accurately with the lowest value that we considered in this study (S∕N = 5). Conclusions. The results of our study suggest that high-resolution near-infrared spectroscopy is a powerful tool for studying exoplanet atmospheres because numerous lines of different molecules can be analyzed simultaneously. Instruments similar to CRIRES+ will provide data for detailed retrieval and will provide new important constraints on the atmospheric chemistry and physics.

scholarly journals TOI-150b and TOI-163b: two transiting hot Jupiters, one eccentric and one inflated, revealed by TESS near and at the edge of the JWST CVZ

2019 ◽  
Vol 490 (1) ◽  
pp. 1094-1110 ◽  
Author(s):  
Diana Kossakowski ◽  
Néstor Espinoza ◽  
Rafael Brahm ◽  
Andrés Jordán ◽  
Thomas Henning ◽  
...  
Keyword(s):  
High Resolution ◽  
Time Scale ◽  
High Resolution Spectroscopy ◽  
Spin Orbit ◽  
Eccentric Orbit ◽  
Hot Jupiters ◽  
Eclipse Observations ◽  
James Webb Space Telescope ◽  
Hot Jupiter

Abstract We present the discovery of TYC9191-519-1b (TOI-150b, TIC 271893367) and HD271181b (TOI-163b, TIC 179317684), two hot Jupiters initially detected using 30-min cadence Transiting Exoplanet Survey Satellite (TESS) photometry from Sector 1 and thoroughly characterized through follow-up photometry (CHAT, Hazelwood, LCO/CTIO, El Sauce, TRAPPIST-S), high-resolution spectroscopy (FEROS, CORALIE), and speckle imaging (Gemini/DSSI), confirming the planetary nature of the two signals. A simultaneous joint fit of photometry and radial velocity using a new fitting package juliet reveals that TOI-150b is a $1.254\pm 0.016\ \rm {R}_ \rm{J}$, massive ($2.61^{+0.19}_{-0.12}\ \rm {M}_ \rm{J}$) hot Jupiter in a 5.857-d orbit, while TOI-163b is an inflated ($R_ \rm{P}$ = $1.478^{+0.022}_{-0.029} \,\mathrm{ R}_ \rm{J}$, $M_ \rm{P}$ = $1.219\pm 0.11 \, \rm{M}_ \rm{J}$) hot Jupiter on a P = 4.231-d orbit; both planets orbit F-type stars. A particularly interesting result is that TOI-150b shows an eccentric orbit ($e=0.262^{+0.045}_{-0.037}$), which is quite uncommon among hot Jupiters. We estimate that this is consistent, however, with the circularization time-scale, which is slightly larger than the age of the system. These two hot Jupiters are both prime candidates for further characterization – in particular, both are excellent candidates for determining spin-orbit alignments via the Rossiter–McLaughlin (RM) effect and for characterizing atmospheric thermal structures using secondary eclipse observations considering they are both located closely to the James Webb Space Telescope (JWST) Continuous Viewing Zone (CVZ).

scholarly journals Detection of neutral atomic species in the ultra-hot Jupiter WASP-121b

2020 ◽  
Vol 494 (1) ◽  
pp. 363-377 ◽  
Author(s):  
Samuel H C Cabot ◽  
Nikku Madhusudhan ◽  
Luis Welbanks ◽  
Anjali Piette ◽  
Siddharth Gandhi
Keyword(s):  
High Resolution ◽  
Transmission Spectrum ◽  
Cross Correlation ◽  
Hydrogen Atmosphere ◽  
Chemical Processes ◽  
Thermal Inversion ◽  
Hot Jupiters ◽  
Roche Limit ◽  
Careful Treatment ◽  
Host Stars

ABSTRACT The class of ultra-hot Jupiters comprises giant exoplanets undergoing intense irradiation from their host stars. They have proved to be a particularly interesting population for their orbital and atmospheric properties. One such planet, WASP-121b, is in a highly misaligned orbit close to its Roche limit, and its atmosphere exhibits a thermal inversion. These properties make WASP-121b an interesting target for additional atmospheric characterization. In this paper, we present analyses of archival high-resolution optical spectra obtained during transits of WASP-121b. We model the Rossiter-McLaughlin effect and the Centre-to-Limb Variation and find that they do not significantly affect the transmission spectrum in this case. However, we discuss scenarios where these effects warrant more careful treatment by modelling the WASP-121 system and varying its properties. We report a new detection of atmospheric absorption from H α in the planet with a transit depth of $1.87\pm 0.11{{\ \rm per\ cent}}$. We further confirm a previous detection of the Na i doublet, and report a new detection of Fe i via cross-correlation with a model template. We attribute the H α absorption to an extended Hydrogen atmosphere, potentially undergoing escape, and the Fe i to equilibrium chemistry at the planetary photosphere. These detections help to constrain the composition and chemical processes in the atmosphere of WASP-121b.

Characterizing HDS209458b and HD189733b with combined High and Low Resolution Spectroscopy

2020 ◽  
Author(s):  
Joe Zalesky ◽  
Michael Line ◽  
Matteo Brogi
Keyword(s):  
High Resolution ◽  
Cross Sections ◽  
Cross Correlation ◽  
Hubble Space Telescope ◽  
Cloud Model ◽  
Correlation Spectroscopy ◽  
Thermal Profile ◽  
Space Telescope ◽  
Exoplanetary Atmospheres ◽  
The Impact

<p>High Resolution Cross Correlation Spectroscopy (HRCCS) has become a powerful tool to constrain both the physical characteristics and abundances of atomic/molecular constituents in exoplanetary atmospheres. Brogi & Line (2019) recently introduced a novel Bayesian atmospheric retrieval methodology that can combine observations from both longer wavelength (2-4 micron), ground-based, HRCCS and shorter wavelength (1-2 micron) space-based observatories such as the Hubble Space Telescope (HST). Here we present results from the application of this technique to both new and previously published observations of HD209458b and HD189733b from VLT/CRIRES, HST, and Spitzer. The more complete wavelength coverage provides a more comprehensive assessment of the atmosphere by way of stronger constraints on the thermal profiles, atmospheric metallicity, and carbon/oxygen inventory for these two benchmark planets. We also investigate the impact of possible model-induced biases including assumptions regarding molecular cross-sections, cloud model prescriptions, and thermal profile parameterizations. Finally, we present what constraints may be possible in the future by performing retrievals of synthetic observations from the next generation of high-resolution spectrographs like CRIRES+. This work has laid a foundational dataset that combines both space and ground-based observations to comprehensively characterize exoplanetary atmospheres and will be a useful benchmark in comparison to future efforts for both transiting and non-transiting atmospheric characterization.</p>

Electron Image Analysis

1971 ◽  
Vol 29 ◽  
pp. 80-81
Author(s):  
D. W. Gibbard ◽  
J. A. Crawley ◽  
M. J. Cowham
Keyword(s):  
Image Analysis ◽  
High Resolution ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Modular Construction ◽  
Wide Range ◽  
Electron Microscopes ◽  
Digital Circuitry ◽  
Accuracy And Repeatability

The history of automatic image analysis is a short one, the techniques being limited until recent years due to the “state of the art” of technology in electronics. A new third generation image analysis machine, the Quantimet 720 was introduced in 1969 designed with a modular construction for application to many fields of interest. It was the first equipment of its type to depart from T.V. standards to scan standards required for optimising the conflicting requirements of high resolution, high speed and high signal to noise ratio. It features high resolution and digital circuitry for accuracy and repeatability and a large and growing range of modules for high computing power. It has also been applied to a wide range of image producing devices including light microscopes, epidiascope (for analysis of photo-micrographs), transmission and scanning electron microscopes.

scholarly journals Alkaline exospheres of exoplanet systems: evaporative transmission spectra

2020 ◽  
Vol 497 (4) ◽  
pp. 5271-5291 ◽  
Author(s):  
Andrea Gebek ◽  
Apurva V Oza
Keyword(s):  
High Resolution ◽  
Cross Sections ◽  
Planetary Atmospheres ◽  
Hydrostatic Equilibrium ◽  
Transmission Spectra ◽  
Absorption Cross ◽  
Density Profiles ◽  
Hot Jupiters ◽  
Exoplanet Systems ◽  
Sodium And Potassium

ABSTRACT Hydrostatic equilibrium is an excellent approximation for the dense layers of planetary atmospheres, where it has been canonically used to interpret transmission spectra of exoplanets. Here, we exploit the ability of high-resolution spectrographs to probe tenuous layers of sodium and potassium gas due to their formidable absorption cross-sections. We present an atmosphere–exosphere degeneracy between optically thick and optically thin mediums, raising the question of whether hydrostatic equilibrium is appropriate for Na i lines observed at exoplanets. To this end we simulate three non-hydrostatic, evaporative, density profiles: (i) escaping, (ii) exomoon, and (iii) torus to examine their imprint on an alkaline exosphere in transmission. By analysing an evaporative curve of growth, we find that equivalent widths of $W_{\mathrm{Na D2}} \sim 1{\!-\!} 10\, \mathrm{m\mathring{\rm A}}$ are naturally driven by evaporation rates ∼103−105 kg s−1 of pure atomic Na. To break the degeneracy between atmospheric and exospheric absorption, we find that if the line ratio is D2/D1 ≳ 1.2 the gas is optically thin on average roughly indicating a non-hydrostatic structure of the atmosphere/exosphere. We show this is the case for Na i observations at hot Jupiters WASP-49b and HD189733b and also simulate their K i spectra. Lastly, motivated by the slew of metal detections at ultra-hot Jupiters, we suggest a toroidal atmosphere at WASP-76b and WASP-121b is consistent with the Na i data at present.

scholarly journals New Chandra/HST-STIS Results on Seyfert I AGN: Photoionized Outflows

2003 ◽  
Vol 214 ◽  
pp. 259-264
Author(s):  
Barry McKernan ◽  
Tahir Yaqoob
Keyword(s):  
High Resolution ◽  
Column Density ◽  
Emission Lines ◽  
High Resolution Spectroscopy ◽  
Type I ◽  
Ionization State ◽  
X Ray ◽  
Spectral Signatures

We present soft X-ray results from observations with Chandra (HETGS) of the Seyfert I AGN NGC 4593 and Mrk 509. We discuss the photoionized outflows associated with Seyfert I AGN in terms of their absorption spectral signatures and discuss their kinematics, column density and ionization state. We discuss the link between UV and X-ray absorbers in Mrk 509 (which was simultaneously observed with Chandra and HST-STIS). We also briefly discuss the possibility of absorption due to neutral Fe embedded in the warm absorber of NGC 4593 versus an interpretation of the data in terms of soft X-ray relativistic emission lines. We conclude with a summary of what is being learnt about warm absorbers in type I AGN from high resolution spectroscopy.

Donor identification in bulk GaAs by Fourier transform photoluminescence

1991 ◽  
Vol 69 (3-4) ◽  
pp. 427-431 ◽  
Author(s):  
D. J. S. Beckett ◽  
M. K. Nissen ◽  
M. L. W. Thewalt
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
High Purity ◽  
Chemical Shifts ◽  
High Resolution Spectroscopy ◽  
High Signal ◽  
High Magnetic Fields ◽  
Bulk Gaas ◽  
Donor Identification ◽  
Small Chemical

The identification of substitutional shallow donors in GaAs by optical techniques has been problematic because of the extremely small chemical shifts of these effective-masslike impurities. Photoluminescence has been successfully applied in identifying donors in high-purity epitaxial material through the painstaking use of high-resolution spectroscopy, high-magnetic fields, and resonant excitation. Relatively little work has been done in bulk GaAs, where the broadened transitions hinder the resolution of different species. Recently we demonstrated that the high resolution and high-signal throughput obtained with Fourier transform photoluminescence (FTPL) gives superior results for epitaxial material. In this report we show that the advantages of FTPL can also be applied to reliable donor identification in bulk GaAs.

scholarly journals Search for He I airglow emission from the hot Jupiter τ Boo b

2020 ◽  
Vol 641 ◽  
pp. A161
Author(s):  
Y. Zhang ◽  
I. A. G. Snellen ◽  
P. Mollière ◽  
F. J. Alonso-Floriano ◽  
R. K. Webb ◽  
...  
Keyword(s):  
High Resolution ◽  
Rest Frame ◽  
Emission Feature ◽  
Emission Lines ◽  
High Resolution Spectroscopy ◽  
Transmission Spectra ◽  
Hot Jupiters ◽  
Line Widths ◽  
Calar Alto ◽  
Metastable Triplet State

Context. It has been suggested that the helium absorption line at 10 830 Å that originates from the metastable triplet state 23S is an excellent probe for the extended atmospheres of hot Jupiters and their hydrodynamic escape processes. It has recently been detected in the transmission spectra of a handful of planets. The isotropic reemission will lead to helium airglow that may be observable at other orbital phases. Aims. We investigate the detectability of He I emission at 10 830 Å in the atmospheres of exoplanets using high-resolution spectroscopy. This would provide insights into the properties of the upper atmospheres of close-in gas giants. Methods. We estimated the expected strength of He I emission in hot Jupiters based on their transmission signal. We searched for the He I 10 830 Å emission feature in τ Boo b in three nights of high-resolution spectra taken by CARMENES at the 3.5m Calar Alto telescope. The spectra from each night were corrected for telluric absorption, sky emission lines, and stellar features, and were shifted to the planetary rest frame to search for the emission. Results. The He I emission is not detected in τ Boo b at a 5σ contrast limit of 4 × 10−4 for emission line widths of >20 km s−1. This is about a factor 8 above the expected emission level (assuming a typical He I transit absorption of 1% for hot Jupiters). This suggests that targeting the He I emission with well-designed observations using upcoming instruments such as VLT/CRIRES+ and E-ELT/HIRES is possible.

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