scholarly journals Tracing bulk elemental ratios in exoplanetary atmospheres with TiO chemistry

2020 ◽  
Vol 641 ◽  
pp. A87
Author(s):  
Vanesa Ramírez ◽  
Alexander J. Cridland ◽  
Paul Mollière
Keyword(s):  
Chemical Properties ◽  
Transmission Spectra ◽  
Elemental Ratios ◽  
Chemical Models ◽  
Bulk Chemical ◽  
Optical Wavelengths ◽  
Exoplanetary Atmospheres ◽  
Molecular Abundances ◽  
Good Agreement ◽  
Hot Jupiter

Deciphering the bulk elemental abundances of exoplanetary atmospheres is not an easy task, yet it is crucial to understanding the formation history of planets. The purpose of this work is to show that the observability of TiO features at optical wavelengths in the transmission spectra of hot Jupiter atmospheres is sensitive to the bulk chemical properties of the atmosphere. To this end, we ran a grid of chemical models, which include TiO formation and destruction, for the ultra-hot Jupiter WASP-19b and an ultra-hot version of HD 209458b. We take into account non-equilibrium chemistry and changes in the temperature and pressure structure of these atmospheres caused by different C/O ratios. We calculated synthetic transmission spectra for these models, and studied the relative strengths of TiO and H2O features quantitatively. To compare with observations, we used a model-independent metric for molecular abundances, ΔZTiO−H2O/Heq, which has previously been used in observational studies of exoplanetary atmospheres. We find that with this metric we can differentiate between different chemical models and place constraints on the bulk carbon and oxygen abundances of the atmosphere. From chemical considerations, we expected the TiO abundance to depend on the bulk nitrogen. However, we find that changes in N/H do not result in changes in the resulting TiO. We applied our method to a set of known exoplanets that have been observed in the relevant optical wavelengths and find good agreement between low-resolution observations and our model for WASP-121b, marginally good agreement with WASP-79b, WASP-76b, and WASP-19b, and poorer agreement with HD 209458b. Our method will be particularly helpful for indirect studies of the bulk abundances of carbon and oxygen.

scholarly journals Infrared Observational Studies of Gas Molecules in Disks

2011 ◽  
Vol 7 (S280) ◽  
pp. 127-137 ◽  
Author(s):  
C. Salyk
Keyword(s):  
Ir Spectroscopy ◽  
Molecular Spectroscopy ◽  
Chemical Properties ◽  
Protoplanetary Disks ◽  
Terrestrial Planet ◽  
Detection Rates ◽  
Line Shapes ◽  
Chemical Models ◽  
Disk Structure ◽  
Molecular Abundances

AbstractThere remain many fundamental unanswered questions about protoplanetary disks, including how (and if?) they form planets, how mass is transferred through the disk and onto the star, and how they ultimately disperse. Also, a major goal of protoplanetary disk studies is to understand the relationship between disk properties and the physical and chemical properties of planetary systems. IR molecular spectroscopy is a particularly powerful tool for probing the conditions and physical process in protoplanetary disks, which are too small and close to their parent stars to be imaged with ease. I will discuss the suite of infrared molecular transitions observed to date, which highlight the following three techniques of IR spectroscopy. Firstly, line shapes and strengths can be used as tracers of disk physics, including volatile condensation/evaporation, photo-processes, grain growth and turbulence. Secondly, observations of multiple molecular abundances provide constraints for disk chemical models, which may ultimately help explain the great diversity of planetary bodies. Finally, resolved line shapes and spectro-astrometry provide a means to study disk structure on extremely small size scales. Because IR observations are typically sensitive to radii of a few AU or smaller, the processes and structures being probed are relevant to the birth and growth of terrestrial and giant planets. Recent results that I will highlight include the discovery of a multitude of molecules in disks around sun-like stars (including H2O, OH, HCN, C2H2 and CO2), with detection rates that depend on stellar mass, constraints on gas mass and location in transitional disks, detection and characterization of ‘snow lines’, measurements of inner disk rims, and detections of inner disk asymmetries. I will also discuss how IR spectroscopy will remain relevant even with the emergence of facilities such as ALMA, as it allows us to connect the conditions in terrestrial-planet-forming regions with those in the cold outer reaches of disks, and to better construct a comprehensive understanding of the nature of protoplanetary disks.

scholarly journals Retrieving the transmission spectrum of HD 209458b usingCHOCOLATE: a new Chromatic Doppler Tomography technique

2021 ◽  
Author(s):  
Emma Esparza-Borges ◽  
Mahmoud Oshagh ◽  
Nuria Casasayas-Barris ◽  
Enric Pallé
Keyword(s):  
Chemical Composition ◽  
Observational Data ◽  
Transmission Spectrum ◽  
Transmission Spectra ◽  
Low Resolution ◽  
Doppler Tomography ◽  
Alternative Approach ◽  
Good Agreement ◽  
Multi Band ◽  
Hot Jupiter

<p>Multi-band photometric transit observations or low resolution spectroscopy (spectro-photometry) are normally used to retrieve the broadband transmission spectra of transiting exoplanets in order to assess the chemical composition of their atmospheres. In this work, we present an alternative approach for recovering the broadband transmission spectra using chromatic Doppler Tomography. To validate the method and examine its performance, we used new observational data obtained with the ESPRESSO instruments to retrieve the  transmission spectra of the archetypal hot Jupiter HD209458b. Our findings indicate that the recovered transmission spectrum is in good agreement with the results presented in previous studies, which used different methodologies to extract the spectrum.</p>

0.94-2.42 μm GROUND-BASED TRANSMISSION SPECTRA OF THE HOT JUPITER HD-189733b

2014 ◽  
Vol 785 (1) ◽  
pp. 35 ◽  
Author(s):  
C. Danielski ◽  
P. Deroo ◽  
I. P. Waldmann ◽  
M. D. J. Hollis ◽  
G. Tinetti ◽  
...  
Keyword(s):  
Transmission Spectra ◽  
Hot Jupiter

scholarly journals Chlorine-bearing molecules in molecular absorbers at intermediate redshifts

2019 ◽  
Vol 629 ◽  
pp. A128 ◽  
Author(s):  
S. H. J. Wallström ◽  
S. Muller ◽  
E. Roueff ◽  
R. Le Gal ◽  
J. H. Black ◽  
...  
Keyword(s):  
Molecular Hydrogen ◽  
Chemical Properties ◽  
Abundance Ratio ◽  
The Other ◽  
Trace Gas ◽  
Line Of Sight ◽  
Isotopic Ratios ◽  
Stellar Nucleosynthesis ◽  
Chemical Models ◽  
Intermediate Redshifts

We use observations of chlorine-bearing species in molecular absorbers at intermediate redshifts to investigate chemical properties and 35Cl/37Cl isotopic ratios in the absorbing sightlines. Chloronium (H2Cl+) is detected along three independent lines of sight in the z = 0.89 and z = 0.68 molecular absorbers located in front of the lensed quasars PKS 1830−211 and B 0218+357, respectively. Hydrogen chloride (HCl) was observed only toward PKS 1830−211, and is found to behave differently from H2Cl+. It is detected in one line of sight with an abundance ratio [H2Cl+] / [HCl] ∼1, but remains undetected in the other, more diffuse, line of sight, with a ratio [H2Cl+] / [HCl] > 17. The absorption profiles of these two chlorine-bearing species are compared to other species and discussed in terms of the physical properties of the absorbing gas. Our findings are consistent with the picture emerging from chemical models where different species trace gas with different molecular hydrogen fraction. The 35Cl/37Cl isotopic ratios are measured in the different lines of sight and are discussed in terms of stellar nucleosynthesis.

Exoplanets: Atmospheres of Hot Jupiters

2019 ◽  
Author(s):  
Dmitry V. Bisikalo ◽  
Pavel V. Kaygorodov ◽  
Valery I. Shematovich
Keyword(s):  
Solar System ◽  
Alternative Hypothesis ◽  
Atmospheric Composition ◽  
Current Status ◽  
Hot Jupiters ◽  
History Of ◽  
Exoplanetary Atmospheres ◽  
Host Stars ◽  
Gaseous Envelopes ◽  
Hot Jupiter

The history of exoplanetary atmospheres studies is strongly based on the observations and investigations of the gaseous envelopes of hot Jupiters—exoplanet gas giants that have masses comparable to the mass of Jupiter and orbital semi-major axes shorter than 0.1 AU. The first exoplanet around a solar-type star was a hot Jupiter discovered in 1995. Researchers found an object that had completely atypical parameters compared to planets known in the solar system. According to their estimates, the object might have a mass about a half of the Jovian mass and a very short orbital period (four days), which means that it has an orbit roughly corresponding to the orbit of Mercury. Later, many similar objects were discovered near different stars, and they acquired a common name—hot Jupiters. It is still unclear what the mechanism is for their origin, because generally accepted theories of planetary evolution predict the formation of giant planets only at large orbital distances, where they can accrete enough matter before the protoplanetary disc disappears. If this is true, before arriving at such low orbits, hot Jupiters might have a long migration path, caused by interactions with other massive planets and/or with the gaseous disc. In favor of this model is the discovery of many hot Jupiters in elliptical and highly inclined orbits, but on the other hand several observed hot Jupiters have circular orbits with low inclination. An alternative hypothesis is that the cores of future hot Jupiters are super-Earths that may later intercept matter from the protoplanetary disk falling on the star. The scientific interest in hot Jupiters has two aspects. The first is the peculiarity of these objects: they have no analogues in the solar system. The second is that, until recently, only for hot Jupiters was it possible to obtain observational characteristics of their atmospheres. Many of the known hot Jupiters are eclipsing their host stars, so, from their light curve and spectral data obtained during an eclipse, it became possible to obtain information about their shape and their atmospheric composition. Thus it is possible to conclude that hot Jupiters are a common type of exoplanet, having no analogues in the solar system. Many aspects of their evolution and internal structure remain unclear. Being very close to their host stars, hot Jupiters must interact with the stellar wind and stellar magnetic field, as well as with stellar flares and coronal mass ejections, allowing researchers to gather information about them. According to UV observations, at least a fraction of hot Jupiters have extended gaseous envelopes, extending far beyond of their upper atmospheres. The envelopes are observable with current astronomical instruments, so it is possible to develop their astrophysical models. The history of hot Jupiter atmosphere studies during the past 20 years and the current status of modern theories describing the extended envelopes of hot Jupiters are excellent examples of the progress in understanding planetary atmospheres formation and evolution both in the solar system and in the extrasolar planetary systems.

scholarly journals Size Determination of Polystyrene Sub-Microspheres Using Transmission Spectroscopy

2020 ◽  
Vol 10 (15) ◽  
pp. 5232
Author(s):  
Tien Van Nguyen ◽  
Linh The Pham ◽  
Khuyen Xuan Bui ◽  
Lien Ha Thi Nghiem ◽  
Nghia Trong Nguyen ◽  
...  
Keyword(s):  
Time Domain ◽  
Finite Difference Time Domain ◽  
Fdtd Simulation ◽  
Transmission Spectra ◽  
Experimental Transmission ◽  
Straightforward Method ◽  
Quartz Substrates ◽  
Difference Time ◽  
Good Agreement

Nano/micro polystyrene (PS) beads have found many applications in different fields spanning from drug delivery, bio-diagnostics, and hybrid plasmonics to advanced photonics. The sizes of the PS beads are an important parameter, especially in plasmonic and photonic experiments. In this work, we demonstrate a quick and straightforward method to estimate the diameters of sub-microspheres (0.2 μm to 0.8 μm) using the transmission spectra of a close-packed monolayer of polystyrene beads on glass or quartz substrates. Experimental transmission spectra of the PS monolayers were verified against finite-difference time-domain (FDTD) simulation and showed good agreement. The effects of the substrates on the transmission spectra and, hence, the accuracy of the method were also studied by simulation, which showed that common transparent substrates only cause minor deviation of the PS bead sizes calculated by the proposed method.

Matrix degradation regulates osteoblast protrusion dynamics and individual migration

2019 ◽  
Vol 11 (11) ◽  
pp. 404-413
Author(s):  
Nieves Movilla ◽  
Clara Valero ◽  
Carlos Borau ◽  
Jose Manuel García-Aznar
Keyword(s):  
Chemical Properties ◽  
Matrix Metalloproteinase Inhibitor ◽  
Surrounding Environment ◽  
Cell Velocity ◽  
The Matrix ◽  
3D Matrix ◽  
A Cell ◽  
Degradation Activity ◽  
Good Agreement ◽  
And Chemical Properties

Abstract Protrusions are one of the structures that cells use to sense their surrounding environment in a probing and exploratory manner as well as to communicate with other cells. In particular, osteoblasts embedded within a 3D matrix tend to originate a large number of protrusions compared to other type of cells. In this work, we study the role that mechanochemical properties of the extracellular matrix (ECM) play on the dynamics of these protrusions, namely, the regulation of the size and number of emanating structures. In addition, we also determine how the dynamics of the protrusions may lead the 3D movement of the osteoblasts. Significant differences were found in protrusion size and cell velocity, when degradation activity due to metalloproteases was blocked by means of an artificial broad-spectrum matrix metalloproteinase inhibitor, whereas stiffening of the matrix by introducing transglutaminase crosslinking, only induced slight changes in both protrusion size and cell velocity, suggesting that the ability of cells to create a path through the matrix is more critical than the matrix mechanical properties themselves. To confirm this, we developed a cell migration computational model in 3D including both the mechanical and chemical properties of the ECM as well as the protrusion mechanics, obtaining good agreement with experimental results.

scholarly journals The physical-chemical properties of substance of the bright fireball EN171101 Turyi Remety

2012 ◽  
Vol 10 (H16) ◽  
pp. 171-171
Author(s):  
Klim Churyumov ◽  
Rudolf Belevtsev ◽  
Emlen Sobotovich ◽  
Svitlana Spivak ◽  
Tetyana Churyumova
Keyword(s):  
Chemical Properties ◽  
Resistance Force ◽  
Physical Parameters ◽  
Magnetic Spheres ◽  
Physical Chemical ◽  
Geochemical Studies ◽  
Cosmic Origin ◽  
Rapid Mass ◽  
Good Agreement ◽  
Propane Butane

AbstractIn 2007-2011 searches were conducted for mineralogical and geochemical studies of the soil in the region of fall down of a bright fireball EN171101 “Turyi Remety“ matter in Perechyn district of Transcarpathian. In the assumed location of the fall of a meteorite material for analysis was taken from the bottom of streams of Transcarpathian Mountains. In this matter we have been found numerous small magnetic spheres (microspherul) and fused segments, which have enough large sizes - up to 5 mm in diameter, which probably are fragments of the Turyi Remety meteoroid. One of the known signs of fireballs are sand-sized magnetic balls (by diameter 0.1-1.0 mm), which are often found in the magnetic concentrate fraction. This small balls, together with fragments of fused iotsit (FeO) are formed during the ablation of the meteoroid, and their sizes decreases during the motion of the meteoroid in the Earths atmosphere. From the east to the west, the radius of the balls in the study area decreased from an average of 0.7-0.5 mm to 0.1-0.3 mm. The sizes of such balls, as glowing molten particles of the meteoroid, are in good agreement with calculations based on the energy loss of the Turyi Remety meteoroid. This confirms the cosmic origin of these found small balls. Pre-calculated physical parameters of the Turyi Remety meteoroid are the velocity, mass, kinetic energy, the resistance force during ablation, the average fireball particle radius along trajectory path of a meteoroid fragments depending from the mass and size. Rapid mass loss of the meteoroid in more than 10 times, stronger, shorter ablation and damping fireball at the high altitude say about instability and the participation of the meteoroid gas in ablation. Perhaps the presence of ice, and other fireball gases in the meteoroid composition shows that its composition was close to comet one or to a chondrite with ice (gas hydrates). Especially likely gaseous hydrates of heavy gases such as CO2, H2S, hydrocarbons (propane, butane, etc.).

scholarly journals Combining low- to high-resolution transit spectroscopy of HD 189733b

2018 ◽  
Vol 612 ◽  
pp. A53 ◽  
Author(s):  
Lorenzo Pino ◽  
David Ehrenreich ◽  
Aurélien Wyttenbach ◽  
Vincent Bourrier ◽  
Valerio Nascimbeni ◽  
...  
Keyword(s):  
High Resolution ◽  
Wavelength Range ◽  
Near Infrared ◽  
Theoretical Models ◽  
Apparent Size ◽  
Transmission Spectra ◽  
Infrared Transmission ◽  
Line Spread Function ◽  
Building Models ◽  
Exoplanetary Atmospheres

Space-borne low- to medium-resolution (ℛ ~ 102–103) and ground-based high-resolution spectrographs (ℛ ~ 105) are commonly used to obtain optical and near infrared transmission spectra of exoplanetary atmospheres. In this wavelength range, space-borne observations detect the broadest spectral features (alkali doublets, molecular bands, scattering, etc.), while high-resolution, ground-based observations probe the sharpest features (cores of the alkali lines, molecular lines). The two techniques differ by several aspects. (1) The line spread function of ground-based observations is ~103 times narrower than for space-borne observations; (2) Space-borne transmission spectra probe up to the base of thermosphere (P ≳ 10−6 bar), while ground-based observations can reach lower pressures (down to ~10−11 bar) thanks to their high resolution; (3) Space-borne observations directly yield the transit depth of the planet, while ground-based observations can only measure differences in the apparent size of the planet at different wavelengths. These differences make it challenging to combine both techniques. Here, we develop a robust method to compare theoretical models with observations at different resolutions. We introduce πη, a line-by-line 1D radiative transfer code to compute theoretical transmission spectra over a broad wavelength range at very high resolution (ℛ ~ 106, or Δλ ~ 0.01 Å). An hybrid forward modeling/retrieval optimization scheme is devised to deal with the large computational resources required by modeling a broad wavelength range ~0.3–2 μm at high resolution. We apply our technique to HD 189733b. In this planet, HST observations reveal a flattened spectrum due to scattering by aerosols, while high-resolution ground-based HARPS observations reveal sharp features corresponding to the cores of sodium lines. We reconcile these apparent contrasting results by building models that reproduce simultaneously both data sets, from the troposphere to the thermosphere. We confirm: (1) the presence of scattering by tropospheric aerosols; (2) that the sodium core feature is of thermospheric origin. When we take into account the presence of aerosols, the large contrast of the core of the sodium lines measured by HARPS indicates a temperature of up to ~10 000K in the thermosphere, higher than what reported in the literature. We also show that the precise value of the thermospheric temperature is degenerate with the relative optical depth of sodium, controlled by its abundance, and of the aerosol deck.

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