scholarly journals Broadband transmission spectroscopy of HD 209458b with ESPRESSO: evidence for Na, TiO, or both

2020 ◽  
Vol 644 ◽  
pp. A51
Author(s):  
N. C. Santos ◽  
E. Cristo ◽  
O. Demangeon ◽  
M. Oshagh ◽  
R. Allart ◽  
...  
Keyword(s):  
High Resolution ◽  
Transmission Spectrum ◽  
Optical Spectrum ◽  
High Resolution Spectroscopy ◽  
Transmission Spectra ◽  
Full Dataset ◽  
Synthetic Spectra ◽  
Observational Errors ◽  
The One

Context. The detection and characterization of exoplanet atmospheres is currently one of the main drivers pushing the development of new observing facilities. In this context, high-resolution spectrographs are proving their potential and showing that high-resolution spectroscopy will be paramount in this field. Aims. We aim to make use of ESPRESSO high-resolution spectra, which cover two transits of HD 209458b, to probe the broadband transmission optical spectrum of the planet. Methods. We applied the chromatic Rossiter–McLaughin method to derive the transmission spectrum of HD 209458b. We compared the results with previous HST observations and with synthetic spectra. Results. We recover a transmission spectrum of HD 209458b similar to the one obtained with HST data. The models suggest that the observed signal can be explained by only Na, only TiO, or both Na and TiO, even though none is fully capable of explaining our observed transmission spectrum. Extra absorbers may be needed to explain the full dataset, though modeling approximations and observational errors can also be responsible for the observed mismatch. Conclusions. Using the chromatic Rossiter–McLaughlin technique, ESPRESSO is able to provide broadband transmission spectra of exoplanets from the ground, in conjunction with space-based facilities, opening good perspectives for similar studies of other planets.

Revisiting the atmosphere of HD 209458b with HARPS-N, CARMENES and ESPRESSO

2020 ◽  
Author(s):  
Núria Casasayas-Barris ◽  
Enric Palle ◽  
Monika Stangret ◽  
Guo Chen ◽  
Fei Yan ◽  
...  
Keyword(s):  
High Resolution ◽  
Time Evolution ◽  
Transmission Spectrum ◽  
State Of The Art ◽  
Signal To Noise Ratio ◽  
Light Curves ◽  
High Resolution Spectroscopy ◽  
Transmission Spectra ◽  
Signal To Noise ◽  
Transmission Spectroscopy

<p>HD 209458b was the first transiting planet discovered, and the first for which its atmosphere, in particular Na I, was detected. With time, it has become one of the most studied planets, with a large diversity of atmospheric studies using low- and high-resolution spectroscopy. Here, we present the analysis of high-resolution transmission spectroscopy of HD 209458b using a total of five transit observations with HARPS-N and CARMENES spectrographs. In contrast to previous studies where atmospheric Na I absorption is detected, we find that, for all of the nights, either individually or combined, the transmission spectra can be explained by the combination of the centre-to-limb variation and the Rossiter-McLaughlin effect. Thus, the transmission spectrum reveals no detectable Na I absorption in HD 209458b. This is also observed in the time-evolution maps and transmission light curves, but at lower signal-to-noise ratio. Other strong lines such as Hα, Ca II IRT, the Mg I triplet region, and K I D1 are analysed, and are also consistent with the modelled effects, without considering any contribution from the exoplanet atmosphere. New ESPRESSO observations, with state-of-the-art stability and considerably larger signal-to-noise, confirm the results of our study and will also be shown.</p>

scholarly journals Spectroscopic characterization of a thermodynamically stable doubly charged diatomic molecule: MgAr2+

2021 ◽  
Author(s):  
Dominik Wehrli ◽  
Matthieu Génévriez ◽  
Frédéric Merkt
Keyword(s):  
High Resolution ◽  
Diatomic Molecule ◽  
Spectroscopic Characterization ◽  
New Method ◽  
High Resolution Spectroscopy ◽  
Singly Charged ◽  
Doubly Charged

We present a new method to study doubly charged molecules relying on high-resolution spectroscopy of the singly charged parent cation, and report on the first spectroscopic characterization of a thermodynamically stable diatomic dication, MgAr2+.

scholarly journals petitRADTRANS

2019 ◽  
Vol 627 ◽  
pp. A67 ◽  
Author(s):  
P. Mollière ◽  
J. P. Wardenier ◽  
R. van Boekel ◽  
Th. Henning ◽  
K. Molaverdikhani ◽  
...  
Keyword(s):  
High Resolution ◽  
Optical Constants ◽  
Emission Spectra ◽  
Transmission Spectra ◽  
Low Resolution ◽  
Cloud Particle ◽  
Hot Jupiters ◽  
Higher Temperature ◽  
Python Package

We present the easy-to-use, publicly available, Python package petitRADTRANS, built for the spectral characterization of exoplanet atmospheres. The code is fast, accurate, and versatile; it can calculate both transmission and emission spectra within a few seconds at low resolution (λ/Δλ = 1000; correlated-k method) and high resolution (λ/Δλ = 106; line-by-line method), using only a few lines of input instruction. The somewhat slower, correlated-k method is used at low resolution because it is more accurate than methods such as opacity sampling. Clouds can be included and treated using wavelength-dependent power law opacities, or by using optical constants of real condensates, specifying either the cloud particle size, or the atmospheric mixing and particle settling strength. Opacities of amorphous or crystalline, spherical or irregularly-shaped cloud particles are available. The line opacity database spans temperatures between 80 and 3000 K, allowing to model fluxes of objects such as terrestrial planets, super-Earths, Neptunes, or hot Jupiters, if their atmospheres are hydrogen-dominated. Higher temperature points and species will be added in the future, allowing to also model the class of ultra hot-Jupiters, with equilibrium temperatures Teq ≳ 2000 K. Radiative transfer results were tested by cross-verifying the low- and high-resolution implementation of petitRADTRANS, and benchmarked with the petitCODE, which itself is also benchmarked to the ATMO and Exo-REM codes. We successfully carried out test retrievals of synthetic JWST emission and transmission spectra (for the hot Jupiter TrES-4b, which has a Teq of ∼1800 K).

scholarly journals Kinematic and chemical analysis of PNe in NGC 3109

2016 ◽  
Vol 12 (S323) ◽  
pp. 390-391
Author(s):  
Sheila N. Flores-Dúran ◽  
Miriam Peña ◽  
María T. Ruiz
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Chemical Analysis ◽  
Stellar Evolution ◽  
Planetary Nebulae ◽  
High Resolution Spectroscopy ◽  
Irregular Galaxy ◽  
The One

AbstractWe present high resolution spectroscopy obtained with MIKE-Magellan and MES OAN-SPM of a number of planetary nebulae (PNe) and H ii regions, distributed along the dwarf irregular galaxy NGC 3109 and compare their kinematical behavior with the one of H i data. We aim to determine if there is a kinematical connection among these objects. We also perform a revision of the chemical composition of PNe and H ii regions in this galaxy and discuss it in comparison with stellar evolution models.

scholarly journals Radial velocity follow-up for confirmation and characterization of transiting exoplanets

2008 ◽  
Vol 4 (S253) ◽  
pp. 129-139 ◽  
Author(s):  
François Bouchy ◽  
Claire Moutou ◽  
Didier Queloz ◽  
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Space Mission ◽  
High Resolution Spectroscopy

AbstractRadial Velocity follow-up is essential to establish or exclude the planetary nature of a transiting companion as well as to accurately determine its mass. Here we present some elements of an efficient Doppler follow-up strategy, based on high-resolution spectroscopy, devoted to the characterization of transiting candidates. Some aspects and results of the radial velocity follow-up of the CoRoT space mission are presented in order to illustrate the strategy used to deal with the zoo of transiting candidates.

scholarly journals Correcting the effect of stellar spots on ARIEL transmission spectra II. The limb darkening effect

2021 ◽  
Author(s):  
G Cracchiolo ◽  
G Micela ◽  
G Morello ◽  
G Peres
Keyword(s):  
Impact Parameter ◽  
Transmission Spectrum ◽  
Stellar Disk ◽  
Transmission Spectra ◽  
Potential Bias ◽  
Temperature Contrast ◽  
Planetary Transmission ◽  
Limb Darkening ◽  
The Impact

Abstract This paper is part of an effort to correct the transmission spectra of a transiting planet orbiting an active star. In Paper I (Cracchiolo et al. 2020) we have demonstrated a methodology to minimize the potential bias induced by unocculted star spots on the transmission spectrum, assuming a spot model parameterized by filling factor and temperature. In this work we introduce the limb darkening effect, therefore the position of the spot in the stellar disk and the impact parameter of the transiting planet now play a key role. The method is tested on simulations of planetary transits of three representative kinds of planetary systems, at ARIEL resolution. We find that a realistic treatment of the limb darkening is required to reliably estimate both the spots parameters and the transmission spectrum of the transiting planet. Furthermore, we show that the influence of the spots on the retrieval of the planetary transmission spectrum is significant for spots close to the center of the star, covering a fraction greater than 0.05 and with a temperature contrast greater than 500 K, and that for these cases our method can confidently extract the transmission spectrum and the impact parameter of the transiting planet for both cases of occulted and not occulted spots, provided that we have an accurate characterization of the stellar parameters and a reliable simulator of the instrument performances.

scholarly journals Characterization of a multi-etalon array for ultra-high resolution spectroscopy

2020 ◽  
Author(s):  
Surangkhana Rukdee ◽  
Sagi Ben-Ami ◽  
Andrew Szentgyorgyi ◽  
Mercedez Lopez-Morales ◽  
David Charbonneau ◽  
...  
Keyword(s):  
High Resolution ◽  
High Resolution Spectroscopy

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.

scholarly journals Stellar contributions to the line profiles of high-resolution transmission spectra of exoplanets

2018 ◽  
Vol 617 ◽  
pp. A134 ◽  
Author(s):  
F. Borsa ◽  
A. Zannoni
Keyword(s):  
High Resolution ◽  
Line Profile ◽  
Transmission Spectrum ◽  
Signal To Noise Ratio ◽  
Transmission Spectra ◽  
Line Profiles ◽  
Stellar Rotation ◽  
Stellar Spectra ◽  
Exoplanetary Atmospheres ◽  
Sophisticated Analysis

Context. In-depth studies of exoplanetary atmospheres are starting to become reality. In order to unveil their properties in detail, we need spectra with a higher signal-to-noise ratio (S/N) and also more sophisticated analysis methods. Aims. With high-resolution spectrographs, we can not only detect the sodium feature in the atmosphere of exoplanets, but also characterize it by studying its line profile. After finding a clearly w-shaped sodium line profile in the transmission spectrum of HD 189733b, we investigated the possible sources of contamination given by the star and tried to correct for these spurious deformations. Methods. By analyzing the single transmission spectra of HD 189733b in the wavelength space, we show that the main sodium signal that causes the absorption in the transmission spectrum is centered on the stellar rest frame. We concentrate on two main stellar effects that contaminate the exoplanetary transmission spectrum: center-to-limb variations (CLVs) and stellar rotation. We show the effects on the line profile: while we correct for the CLV using simulated theoretical stellar spectra, we provide a new method, based directly on observational data, to correct for the Rossiter–McLaughlin contribution to the line profile of the retrieved transmission spectrum. Results. We apply the corrections to the spectra of HD 189733b. Our analysis shows line profiles of the Na D lines in the transmission spectrum that are narrower than reported previously. The correction of the sodium D2 line, which is deeper than the D1 line, is probably still incomplete since the planetary radius is larger at this wavelength. A careful detrending from spurious stellar effects followed by an inspection in the velocity space is mandatory when studying the line profile of atmospheric features in the high-resolution transmission spectrum of exoplanets. Since the line profile is used to retrieve atmospheric properties, the resulting atmospheric parameters could be incorrectly estimated when the stellar contamination is not corrected for. Data with higher S/N coupled with improved atmospheric models will allow us to adapt the magnitude of the corrections of stellar effects in an iterative way.

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