Metals in the day-side of ultra-hot Jupiter atmospheres: a key test for planetary formation

2020 ◽  
Author(s):  
Lorenzo Pino ◽  
Jean-Michel Désert ◽  
Matteo Brogi ◽  
Valerio Nascimbeni ◽  
Aldo Stefano Bonomo ◽  
...  
Keyword(s):  
Emission Spectrum ◽  
Planet Formation ◽  
High Spectral Resolution ◽  
Optical Data ◽  
Thermal Inversion ◽  
Hot Jupiters ◽  
Refractory Elements ◽  
Metal Abundances ◽  
A New Technique ◽  
Side Emission

<p>Ultra-hot Jupiters (T<sub>eq</sub> ≥ 2,500 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. Thousands of lines of refractory elements such as iron, normally inaccessible in planets, can be studied through high spectral resolution emission spectroscopy, providing a first look into the chemistry of refractory elements in exoplanets. In this talk we report the detection of neutral iron in the day-side emission spectrum of KELT-9b (T<sub>day</sub> ~ 4,000<span>  </span>K), the first detection of an atomic species in the emission spectrum of an exoplanet, obtained with HARPS-N optical data gathered in the framework of the GAPS collaboration. Our detection unambiguously indicates the presence of a thermal inversion in the atmosphere of the planet. We also present a new technique to extract planetary parameters from the cross-correlation function in a statistically sound framework, which makes possible the combination with information from the planetary continuum that can be obtained with complementary space facilities.<span> </span>This is a crucial step towards the measurement of metal abundances in exoplanets, a quantity that can be compared to predictions of planet formation theories. In the near future, our technique will be extended to cooler exoplanets. In the era of EELTs and JWST, this kind of measurements could ultimately open a new window on exoplanet formation and evolution.</p>

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>

Characterising Two Ultra-Hot Jupiters with the Hubble Space Telescope

2020 ◽  
Author(s):  
Billy Edwards ◽  
Quentin Changeat ◽  
William Pluriel ◽  
Niall Whiteford ◽  
Kai Hou Yip ◽  
...  
Keyword(s):  
Emission Spectrum ◽  
Hubble Space Telescope ◽  
Cloud Model ◽  
Thermal Structure ◽  
Emission Spectra ◽  
Pressure Profile ◽  
Wide Field ◽  
Space Telescope ◽  
Thermal Inversion ◽  
Hot Jupiters

<p>The Hubble Space Telescope’s Wide Field Camera 3 (WFC3) has been widely used for transmission and emission spectroscopy of exoplanet atmospheres, identifying the main molecular constituents, detecting the presence of clouds and probing their thermal structure. Hubble observations of the emission spectra of a number of ultra-hot Jupiters have led to somewhat surprising results. Initially, these very hot planets were predicted to have inverted temperature pressure profiles due to strong optical absorption by TiO/VO in the upper atmospheres. However, observations of their emission spectra have been inconclusive on their thermal structure and composition. While some datasets show rich spectral features, others can be fit with simple blackbody models.</p> <p>We will present the analysis of Hubble WFC3 transmission and emission spectra for two ultra-hot Jupiters: WASP-76 b and KELT-7 b. In each case, the data was reduced and fitted using the open-source codes Iraclis and Taurex3. Previous studies of the WFC3 transmission spectra of WASP-76 b found hints of TiO and VO or non-grey clouds. Accounting for a fainter stellar companion to WASP-76, we reanalyse this data and show that removing the effects of this background star changes the slope of the spectrum, resulting in these visible absorbers no longer being detected, removing the need for a non-grey cloud model to adequately fit the data but maintaining the strong water feature previously seen. However, our analysis of the emission spectrum suggests the presence of titanium oxide (TiO) and an atmospheric thermal inversion. Meanwhile, our study of KELT-7 b uncovers a rich transmission spectrum which suggests the presence of water and H-. In contrast, the extracted emission spectrum does not contain strong absorption features and, although it is not consistent with a simple blackbody, it can be explained by a varying temperature-pressure profile, collision induced absorption (CIA) and H-. </p> <p>These finding bring new insights into the nature of this intriguing class of planets but more data is required to fully understand them and thus we will also present the anticipated results of further characterisation.</p>

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.

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 Characterizing the Atmospheres of Hot Jupiters: From Spectra to Multi-Color Maps

2008 ◽  
Vol 4 (S253) ◽  
pp. 255-261
Author(s):  
Heather A. Knutson
Keyword(s):  
Emission Spectrum ◽  
Inversion Layer ◽  
Emission Spectra ◽  
Phase Curve ◽  
Hot Jupiters ◽  
Thermal Phase ◽  
Additional Support ◽  
Temperature Inversions ◽  
The Relationship ◽  
Hot Jupiter

AbstractWe present new observations of the emission spectrum of the hot Jupiter TrES-4 designed to test the theory that the presence of temperature inversions in the atmospheres of these planets are correlated with the amount of radiation received by the planet. Our observations reveal that TrES-4 has an emission spectrum similar to that of HD 209458b, which requires the presence of an inversion layer high in the atmosphere and water emission bands in order to explain the observed features, providing additional support for that theory. We also present new observations of the thermal phase curve of HD 189733b at 24 μm, which we combine with our previous observations at 8 μm to examine how circulation in this planet's atmosphere varies as a function of depth. We discuss the relationship between the strength of the day-night circulation on both planets and their other observable properties, in particular their emission spectra.

scholarly journals The Rossiter-McLaughlin effect for exoplanets

2010 ◽  
Vol 6 (S276) ◽  
pp. 230-237
Author(s):  
Joshua N. Winn
Keyword(s):  
Measurement Technique ◽  
Planet Formation ◽  
Hot Jupiters ◽  
Transiting Planets ◽  
History Of ◽  
And Migration

AbstractThere are now more than 35 stars with transiting planets for which the stellar obliquity—or more precisely its sky projection—has been measured, via the eponymous effect of Rossiter and McLaughlin. The history of these measurements is intriguing. For 8 years a case was gradually building that the orbits of hot Jupiters are always well-aligned with the rotation of their parent stars. Then in a sudden reversal, many misaligned systems were found, and it now seems that even retrograde systems are not uncommon. I review the measurement technique underlying these discoveries, the patterns that have emerged from the data, and the implications for theories of planet formation and migration.

scholarly journals Connecting planet formation and astrochemistry

2019 ◽  
Vol 632 ◽  
pp. A63 ◽  
Author(s):  
Alex J. Cridland ◽  
Ewine F. van Dishoeck ◽  
Matthew Alessi ◽  
Ralph E. Pudritz
Keyword(s):  
Solar System ◽  
Planet Formation ◽  
Water Ice ◽  
Hot Jupiters ◽  
Formation History ◽  
General Mass ◽  
Exoplanetary Atmospheres ◽  
Molecular Abundances ◽  
Gas Accretion ◽  
Oxygen Ratio

To understand the role that planet formation history has on the observable atmospheric carbon-to-oxygen ratio (C/O) we have produced a population of astrochemically evolving protoplanetary disks. Based on the parameters used in a pre-computed population of growing planets, their combination allows us to trace the molecular abundances of the gas that is being collected into planetary atmospheres. We include atmospheric pollution of incoming (icy) planetesimals as well as the effect of refractory carbon erosion noted to exist in our own solar system. We find that the carbon and oxygen content of Neptune-mass planets are determined primarily through solid accretion and result in more oxygen-rich (by roughly two orders of magnitude) atmospheres than hot Jupiters, whose C/O are primarily determined by gas accretion. Generally we find a “main sequence” between the fraction of planetary mass accreted through solid accretion and the resulting atmospheric C/O; planets of higher solid accretion fraction have lower C/O. Hot Jupiters whose atmospheres have been chemically characterized agree well with our population of planets, and our results suggest that hot-Jupiter formation typically begins near the water ice line. Lower mass hot Neptunes are observed to be much more carbon rich (with 0.33 ≲ C/O ≲ 1) than is found in our models (C/O ~ 10−2), and suggest that some form of chemical processing may affect their observed C/O over the few billion years between formation and observation. Our population reproduces the general mass-metallicity trend of the solar system and qualitatively reproduces the C/O metallicity anti-correlation that has been inferred for the population of characterized exoplanetary atmospheres.

Wind of Change: Atmospheric wind retrieval and its implications for hot Jupiters

2020 ◽  
Author(s):  
Julia Seidel ◽  
David Ehrenreich ◽  
Vincent Bourrier ◽  
Lorenzo Pino ◽  
Aurelien Wyttenbach ◽  
...  
Keyword(s):  
High Spectral Resolution ◽  
Wind Retrieval ◽  
Hot Jupiters ◽  
Global Circulation ◽  
Hot Gas ◽  
Global Circulation Models ◽  
Pressure Profiles ◽  
Profile Fitting ◽  
Wide Range ◽  
Hot Jupiter

<p><span>The sodium doublet is one of the most powerful probes of exoplanet atmospheric properties when observed in transmission spectroscopy during transits. Recent high-spectral resolution observations of the sodium doublet in hot gas giants allowed us to resolve the line shape, opening the way for extracting atmospheric properties using line-profile fitting. </span></p><p><span>Using the MERC code (Seidel et al. 2020a), a retrieval tool to determine temperature-pressure profiles and high-altitude winds in exoplanet thermospheres, we have studied the curiously broadened sodium signatures of various hot Jupiters. We have updated the MERC code to a quasi 3D treatment of the atmosphere (Seidel et al. 2020c, in prep.) and analysed three hot Jupiters, spanning a wide range of this class of exoplanets (see figure). Using the sodium signature of three examples - WASP-76b (a highly irradiated ultra-hot Jupiter, Seidel et al. 2019), KELT-11b (a puffy hot Jupiter, Mounzer et al. 2020, in prep.), and lastly HD189733b (one of the most studied hot Jupiters to date, Wyttenbach et al. 2015) - we explore possible trends in the atmospheric structure of hot Jupiters.</span></p><p><span>We will first introduce the new quasi 3D retrieval of MERC, and proceed to show that high-velocity winds in the thermosphere are one possible explanation of the broadened sodium features seen in hot Jupiters. We plan to highlight various caveats and present likely origin scenarios for the observed wind patterns. We will then put these results in the context of past studies using global circulation models (GCMs) on hot Jupiters.</span></p><p><img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gnp.2223b4ea02fe54080292951/sdaolpUECMynit/0202CSPE&app=m&a=0&c=4c9f1f886978a365f195c38f0ef4783d&ct=x&pn=gnp.elif" alt=""></p>

The Emission Spectrum of the CO2+ Ion: Band System

1975 ◽  
Vol 53 (19) ◽  
pp. 2040-2059 ◽  
Author(s):  
D. Gauyacq ◽  
M. Horani ◽  
S. Leach ◽  
J. Rostas
Keyword(s):  
Emission Spectrum ◽  
Spectral Resolution ◽  
Band System ◽  
High Spectral Resolution ◽  
Vibronic Transition ◽  
Electronic Band ◽  
Rotational Constants ◽  
Band Origin ◽  
Resolution Analysis ◽  
Vibronic Level

The [Formula: see text] and [Formula: see text] transitions of the CO2+ ion were photographed in emission under high spectral resolution. Analysis of the electronic band origin of the [Formula: see text] transition has provided rotational constants which are more refined and extensive than those previously known. The presence of a perturbation at J′ ~ 36.5 in the [Formula: see text] vibronic level was confirmed and a second stronger perturbation was shown to exist for values of J′ < 20.5.The four subbands 0110 2Πg–0100 μ2Σu, 0110 2Πg–0120 2Δu5/2, 0110 2Πg–0120 2Δu3/2, and 0110 2Πg–0100 κ2Σu of the Renner–Teller split [Formula: see text] vibronic transition 010–010 were identified and rotationally analyzed. The results lead to values of [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text].

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.

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