scholarly journals Exoplanet atmospheres at high spectral resolution: A CRIRES survey of hot-Jupiters

2010 ◽  
Vol 6 (S276) ◽  
pp. 208-211
Author(s):  
Ignas Snellen ◽  
Remco de Kok ◽  
Ernst de Mooij ◽  
Matteo Brogi ◽  
Bas Nefs ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Spectral Resolution ◽  
High Spectral Resolution ◽  
Mass Composition ◽  
Large Telescope ◽  
Test Bed ◽  
Echelle Spectrograph ◽  
Hot Jupiters ◽  
Transiting Planets ◽  
Very Large Telescope

AbstractRecently, we presented the detection of carbon monoxide in the transmission spectrum of extrasolar planet HD209458b, using CRIRES, the Cryogenic high-resolution Infrared Echelle Spectrograph at ESO's Very Large Telescope (VLT). The high spectral resolution observations (R=100,000) provide a wealth of information on the planet's orbit, mass, composition, and even on its atmospheric dynamics. The new observational strategy and data analysis techniques open up a whole world of opportunities. We therefore started an ESO large program using CRIRES to explore these, targeting both transiting and non-transiting planets in carbon monoxide, water vapour, and methane. Observations of the latter molecule will also serve as a test-bed for METIS, the proposed mid-infrared imager and spectrograph for the European Extremely Large Telescope.

scholarly journals Physical conditions and chemical abundances in PN M 2-36. Results from deep echelle observations

2021 ◽  
Author(s):  
José N Espíritu ◽  
Antonio Peimbert
Keyword(s):  
Chemical Structure ◽  
Ultra Violet ◽  
Emission Lines ◽  
High Spectral Resolution ◽  
Large Telescope ◽  
Echelle Spectrograph ◽  
Chemical Abundances ◽  
Physical Conditions ◽  
Very Large Telescope ◽  
Physical And Chemical

Abstract We present a spectrum of the planetary nebula M 2-36 obtained using the Ultra Violet and Visual Echelle Spectrograph (UVES) at the Very Large Telescope (VLT). 446 emission lines are detected. We perform an analysis of the chemical composition using multiple electron temperature (Te) and density (ne) diagnostics. Te and ne are computed using a variety of methods, including collisionally excited line (CEL) ratios, O++ optical recombination lines (ORLs), and measuring the intensity of the Balmer jump. Besides the classical CEL abundances, we also present robust ionic abundances from ORLs of heavy elements. From CELs and ORLs of O++, we obtain a new value for the Abundance Discrepancy Factor (ADF) of this nebula, being ADF(O++) = 6.76 ± 0.50. From all the different line ratios that we study, we find that the object cannot be chemically homogeneous; moreover, we find that two-phased photoionization models are unable to simultaneously reproduce critical ${\rm O\, \small {II}}$ and [${\rm O\, \small {III}}$] line ratios. However, we find a three-phased model able to adequately reproduce such ratios. While we consider this to be a toy model, it is able to reproduce the observed temperature and density line diagnostics. Our analysis shows that it is important to study high ADF PNe with high spectral resolution, since its physical and chemical structure may be more complicated than previously thought.

Searching for 3D effects in the optical, high spectral resolution emission spectrum of KELT-9b

2021 ◽  
Author(s):  
Lorenzo Pino ◽  
Matteo Brogi ◽  
Jean-Michel Désert ◽  
Emily Rauscher
Keyword(s):  
Emission Spectrum ◽  
Spectral Resolution ◽  
Planet Formation ◽  
Emission Spectra ◽  
Optical Emission ◽  
High Spectral Resolution ◽  
Optical Emission Spectrum ◽  
Hot Jupiters ◽  
Atmospheric Structure ◽  
3D Effects

<p>Ultra-hot Jupiters (UHJs; T<sub>eq</sub> ≥ 2500 K) are the hottest gaseous giants known. They emerged as ideal laboratories to test theories of atmospheric structure and its link to planet formation. Indeed, because of their high temperatures, (1) they likely host atmospheres in chemical equilibrium and (2) clouds do not form in their day-side. Their continuum, which can be measured with space-facilities, can be mostly attributed to H- opacity, an indicator of metallicity. From the ground, the high spectral resolution emission spectra of UHJs contains thousands of lines of refractory (Fe, Ti, TiO, …) and volatile species (OH, CO, …), whose combined atmospheric abundances could track planet formation history in a unique way. In this talk, we take a deeper look to the optical emission spectrum of KELT-9b covering planetary phases 0.25 - 0.75 (i.e. between secondary eclipse and quadrature), and search for the effect of atmospheric dynamics and three-dimensionality of the planet atmosphere on the resolved line profiles, in the context of a consolidated statistical framework. We discuss the suitability of the traditionally adopted 1D models to interprete phase-resolved observations of ultra-hot Jupiters, and the potential of this kind of observations to probe their 3D atmospheric structure and dynamics. Ultimately, understanding which factors affect the line-shape in UHJs will also lead to more accurate and more precise abundance measurements, opening a new window on exoplanet formation and evolution.</p>

scholarly journals The full infrared spectrum of molecular hydrogen

2019 ◽  
Vol 630 ◽  
pp. A58 ◽  
Author(s):  
E. Roueff ◽  
H. Abgrall ◽  
P. Czachorowski ◽  
K. Pachucki ◽  
M. Puchalski ◽  
...  
Keyword(s):  
Infrared Spectrum ◽  
Magnetic Dipole ◽  
Molecular Hydrogen ◽  
Radiative Lifetime ◽  
Electric Quadrupole ◽  
Molecular State ◽  
High Spectral Resolution ◽  
Echelle Spectrograph ◽  
Very Large Telescope ◽  
Magnetic Dipole Transitions

Context. The high spectral resolution R ∼ 45 000 provided by IGRINS (Immersion Grating INfrared Spectrometer) at MacDonald Observatory and R ∼ 100 000 achieved by CRIRES (CRyogenic high-resolution InfraRed Echelle Spectrograph) at VLT (Very Large Telescope) challenges the present knowledge of infrared spectra. Aims. We aim to predict the full infrared spectrum of molecular hydrogen at a comparable accuracy. Methods. We take advantage of the recent theoretical ab initio studies on molecular hydrogen to compute both the electric quadrupole and magnetic dipole transitions taking place within the ground electronic molecular state of hydrogen. Results. We computed the full infrared spectrum of molecular hydrogen at an unprecedented accuracy and derive for the first time the emission probabilities including both electric quadrupole (ΔJ = 0, ±2) and magnetic dipole transitions (ΔJ = 0) as well as the total radiative lifetime of each rovibrational state. Inclusion of magnetic dipole transitions increases the emission probabilities by factors of a few for highly excited rotational levels, which occur in the 3–20 μ range.

scholarly journals Non-detection of TiO and VO in the atmosphere of WASP-121b using high-resolution spectroscopy

2020 ◽  
Vol 636 ◽  
pp. A117 ◽  
Author(s):  
S. R. Merritt ◽  
N. P. Gibson ◽  
S. K. Nugroho ◽  
E. J. W. de Mooij ◽  
M. J. Hooton ◽  
...  
Keyword(s):  
Correlation Method ◽  
Detection Limits ◽  
Temperature Inversion ◽  
High Resolution Spectroscopy ◽  
Echelle Spectrograph ◽  
Thermal Inversion ◽  
Hot Jupiters ◽  
Very Large Telescope ◽  
Excess Absorption ◽  
Rule Out

Thermal inversions have long been predicted to exist in the atmospheres of ultra-hot Jupiters. However, the detection of two species thought to be responsible – titanium oxide and vanadium oxide – remains elusive. We present a search for TiO and VO in the atmosphere of the ultra-hot Jupiter WASP-121b (Teq ≳ 2400 K), an exoplanet with evidence of VO in its atmosphere at low resolution which also exhibits water emission features in its dayside spectrum characteristic of a temperature inversion. We observed its transmission spectrum with the UV-Visual Echelle Spectrograph at the Very Large Telescope and used the cross-correlation method – a powerful tool for the unambiguous identification of the presence of atomic and molecular species – in an effort to detect whether TiO or VO were responsible for the observed temperature inversion. No evidence for the presence of TiO or VO was found at the terminator of WASP-121b. By injecting signals into our data at varying abundance levels, we set rough detection limits of [VO] ≲−7.9 and [TiO] ≲−9.3. However, these detection limits are largely degenerate with scattering properties and the position of the cloud deck. Our results may suggest that neither TiO or VO are the main drivers of the thermal inversion in WASP-121b; however, until a more accurate line list is developed for VO, we cannot conclusively rule out its presence. Future works will consist of a search for other strong optically-absorbing species that may be responsible for the excess absorption in the red-optical.

scholarly journals Spatially resolving the thermally inhomogeneous outer atmosphere of the red giant Arcturus in the 2.3 μm CO lines

2018 ◽  
Vol 620 ◽  
pp. A23 ◽  
Author(s):  
K. Ohnaka ◽  
C. A. L. Morales Marín
Keyword(s):  
Spectral Resolution ◽  
Column Density ◽  
High Spectral Resolution ◽  
Molecular Gas ◽  
Very Large Telescope ◽  
Extended Component ◽  
Outer Atmosphere ◽  
Red Giant ◽  
The Individual ◽  
Photospheric Model

Aim. The outer atmosphere of K giants shows thermally inhomogeneous structures consisting of the hot chromospheric gas and the cool molecular gas. We present spectro-interferometric observations of the multicomponent outer atmosphere of the well-studied K1.5 giant Arcturus (α Boo) in the CO first overtone lines near 2.3 μm. Methods. We observed Arcturus with the AMBER instrument at the Very Large Telescope Interferometer (VLTI) at 2.28–2.31 μm with a spectral resolution of 12 000 and at projected baselines of 7.3, 14.6, and 21.8 m. Results. The high spectral resolution of the VLTI/AMBER instrument allowed us to spatially resolve Arcturus in the individual CO lines. Comparison of the observed interferometric data with the MARCS photospheric model shows that the star appears to be significantly larger than predicted by the model. It indicates the presence of an extended component that is not accounted for by the current photospheric models for this well-studied star. We found out that the observed AMBER data can be explained by a model with two additional CO layers above the photosphere. The inner CO layer is located just above the photosphere, at 1.04 ± 0.02 R⋆, with a temperature of 1600 ± 400 K and a CO column density of 1020 ± 0.3 cm−2. On the other hand, the outer CO layer is found to be as extended as to 2.6 ± 0.2 R⋆ with a temperature of 1800 ± 100 K and a CO column density of 1019 ± 0.15 cm−2. Conclusions. The properties of the inner CO layer are in broad agreement with those previously inferred from the spatially unresolved spectroscopic analyses. However, our AMBER observations have revealed that the quasi-static cool molecular component extends out to 2–3 R⋆, within which region the chromospheric wind steeply accelerates.

scholarly journals A Subsystem Test Bed for Chinese Spectral Radioheliograph

2014 ◽  
Vol 31 ◽  
Author(s):  
An Zhao ◽  
Yihua Yan ◽  
Wei Wang
Keyword(s):  
Spectral Resolution ◽  
High Speed ◽  
Digital Signal ◽  
Digital Processing ◽  
Intermediate Frequency ◽  
High Spectral Resolution ◽  
High Temporal Resolution ◽  
Test Bed ◽  
Software Algorithms ◽  
High Speed Data

AbstractThe Chinese Spectral Radioheliograph is a solar dedicated radio interferometric array that will produce high spatial resolution, high temporal resolution, and high spectral resolution images of the Sun simultaneously in decimetre and centimetre wave range. Digital processing of intermediate frequency signal is an important part in a radio telescope. This paper describes a flexible and high-speed digital down conversion system for the CSRH by applying complex mixing, parallel filtering, and extracting algorithms to process IF signal at the time of being designed and incorporates canonic-signed digit coding and bit-plane method to improve program efficiency. The DDC system is intended to be a subsystem test bed for simulation and testing for CSRH. Software algorithms for simulation and hardware language algorithms based on FPGA are written which use less hardware resources and at the same time achieve high performances such as processing high-speed data flow (1 GHz) with 10 MHz spectral resolution. An experiment with the test bed is illustrated by using geostationary satellite data observed on March 20, 2014. Due to the easy alterability of the algorithms on FPGA, the data can be recomputed with different digital signal processing algorithms for selecting optimum algorithm.

EXES: The Echelon-cross-echelle Spectrograph for SOFIA

2018 ◽  
Vol 07 (04) ◽  
pp. 1840013 ◽  
Author(s):  
M. J. Richter ◽  
C. N. DeWitt ◽  
M. McKelvey ◽  
E. Montiel ◽  
R. McMurray ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Infrared Astronomy ◽  
High Spectral Resolution ◽  
Echelle Spectrograph ◽  
Mid Infrared ◽  
Low Background ◽  
And Performance ◽  
Operational Modes ◽  
Echelon Grating

The Echelon-cross-echelle spectrograph (EXES) is a high spectral resolution, mid-infrared spectrograph designed for and operated on the Stratospheric Observatory for Infrared Astronomy (SOFIA). EXES has multiple operational modes, but is optimized for high spectral resolution. The heart of the instrument is a one meter long, diamond-machined echelon grating. EXES also uses a 10242 Si:As detector optimized for low-background flux. We will discuss the design, operation and performance of EXES.

An Experiment Using High Spectral Resolution CrIS Measurements for Atmospheric Trace Gases: Carbon Monoxide Retrieval Impact Study

2014 ◽  
Vol 11 (9) ◽  
pp. 1639-1643 ◽  
Author(s):  
Antonia Gambacorta ◽  
Christopher Barnet ◽  
Walter Wolf ◽  
Thomas King ◽  
Eric Maddy ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Spectral Resolution ◽  
Trace Gases ◽  
High Spectral Resolution ◽  
Impact Study ◽  
Atmospheric Trace Gases

scholarly journals Probing the atmosphere of HD189733b with the Na i and K i lines

2020 ◽  
Vol 498 (1) ◽  
pp. 1023-1033
Author(s):  
E Keles ◽  
D Kitzmann ◽  
M Mallonn ◽  
X Alexoudi ◽  
L Fossati ◽  
...  
Keyword(s):  
High Resolution ◽  
High Altitude ◽  
Spectral Resolution ◽  
Absorption Lines ◽  
High Spectral Resolution ◽  
Transmission Spectra ◽  
Line Profiles ◽  
Line Broadening ◽  
Atmospheric Processes ◽  
Hot Jupiters

ABSTRACT High spectral resolution transmission spectroscopy is a powerful tool to characterize exoplanet atmospheres. Especially for hot Jupiters, this technique is highly relevant, due to their high-altitude absorption, e.g. from resonant sodium (Na i) and potassium (K i) lines. We resolve the atmospheric K i absorption on HD189733b with the aim to compare the resolved K i line and previously obtained high-resolution Na i-D line observations with synthetic transmission spectra. The line profiles suggest atmospheric processes leading to a line broadening of the order of ∼10 km/s for the Na i-D lines and only a few km/s for the K i line. The investigation hints that either the atmosphere of HD189733b lacks a significant amount of K i or the alkali lines probe different atmospheric regions with different temperature, which could explain the differences we see in the resolved absorption lines.

scholarly journals The New Coudé Échelle Spectrograph for the Anglo Australian Telescope

1984 ◽  
Vol 79 ◽  
pp. 499-513
Author(s):  
David D. Walker ◽  
Francisco Diego
Keyword(s):  
Advisory Committee ◽  
Optical System ◽  
Spectral Resolution ◽  
Mechanical Design ◽  
Complete System ◽  
High Spectral Resolution ◽  
Advanced Stage ◽  
Echelle Spectrograph ◽  
University College ◽  
University College London

During 1983, the advisory committee for instrumentation at the Anglo Australian Telescope (AAT) recommended that, as a matter of high priority, an échelle spectrograph should be procured for the f/36 coudé focus. The aim was to satisfy the high spectral-resolution needs of the community which, hereto, have been neglected. We at University College London (UCL) were invited to consider the design and our proposal was subsequently accepted by the Board. We are now at an advanced stage in optimizing the optical system, and mechanical design is proceeding. We plan to test the complete system in the laboratory at UCL prior to installation and commissioning at the AAT which we anticipate will be during 1987.

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