High resolution spectroscopy has proven a powerful and highly versatile tool in the characterization of exoplanet atmospheres. Over the last decade we have explored the rich detail that its sensitivity to the position and shape of exoplanet spectral lines provides, and with robustness thanks to the unique pattern of lines that each species exhibits at such high resolution. In this talk, I will...
Ultra hot Jupiters around bright stars are the most favorable targets for high-resolution exoplanetary spectroscopy. We present our emission and transmission spectroscopy observations of the ultra hot Jupiter KELT-20 b/MASCARA-2 b from PEPSI on LBT, with R=130,000. With the LBT's large aperture we obtain some of the highest signal-to-noise ratio exoplanetary spectra to date (stellar spectra...
High-resolution (HR) ground-based spectrographs have drastically improved the investigation of exoplanet atmospheres.
We will present results obtained within the GAPS 2.0 long-term program for atmospheric characterization of hot giant planets using the near-infrared 0.95-2.45 \mu m) arm of GIARPS: the high-resolution (R /sim 50 000) spectrograph GIANO-B of the Telescopio Nazionale Galileo...
We present High Resolution Cross Correlation Spectroscopy (HRCCS) observations and atmospheric retrieval results of the Ultra Hot Jupiter, MASCARA-1b. HRCCS is a novel technique used to characterize exoplanets with ground-based instruments by utilizing the planet's time-resolved Doppler shifted signal to separate it from the dominant stellar and telluric lines. The high spectral resolution...
The holistic understanding of exoplanet atmospheres continues to elude us due to the difficulty in acquiring data for these far-away worlds. A wide array of techniques is necessary to probe their components, structure, and interactions. One of these techniques has proven to be particularly effective for large and highly irradiated exoplanets: Ground-based, narrow-band transmission spectroscopy...
State-of-the-art spectrographs on large ground-based telescopes have allowed significant discoveries in the structure, composition and dynamic processes of exoplanetary atmospheres through high-resolution transit spectroscopy. However, observations from ground-based facilities face two major challenges : The day-night cycle limits the length of observations, and incoming signals are distorted...
High-resolution transmission spectroscopy has opened new avenues in which to characterise the atmospheres of exoplanets. This technique has been used to unambiguously identify chemical species, map longitudinal variations in their abundance across the morning and evening limbs, as well as to infer atmospheric dynamics. We present multiple high-resolution transmission spectroscopy observations...
Planets on misaligned orbits around rapid rotators can experience “gravity-darkened seasons” as their orbits cross over the hot poles and cooler equators of rotationally-flattened stars. The periodically variable heating from these seasons presents a unique case for exploring how changes in stellar irradiation influence planetary atmospheric dynamics. We perform a homogeneous analysis of...
While first detections of atmospheric species were based on medium-to low resolution data from space, ground-based facilities have majorly contributed to our understanding of these far-away worlds since then.
To a large part this is owed to the use of high-resolution spectroscopy, which allows us to identify the resolved lines of metals and molecules in the optical and infrared wavelength...
Retrievals on high spectral resolution exoplanet observations have been recently made possible, allowing us now to place robust, quantitative constraints on their atmospheres in unprecedented detail. High resolution data can also be combined with low resolution, space-based data in retrievals, probing a wider range of altitudes and incorporating continuum information otherwise lost through...
The ultra-hot Jupiter WASP-33b shows evidence for a thermal inversion in the form of emission lines of atoms and molecules, including OH and Fe. Phase-curve measurements at optical wavelengths with TESS show a westward phase-offset while observations in the infrared with the Spitzer Space Telescope show an Eastward offset. We obtained phase-curve observations at high-spectral resolution at...
We present Keck/KPIC high-resolution ($R\sim35,000$) $K$-band thermal emission spectroscopy of the ultra-hot Jupiter WASP-33b. The use of KPIC's single-mode fiber greatly improves both blaze and line-spread stabilities relative to slit spectrographs, enhancing the cross-correlation detection strength. We perform separate retrievals for the dayside and nightside emission spectra with a...
Characterisation of exoplanet atmospheres using high-resolution spectra provides a unique window into their composition, dynamics as well as their formation and evolution pathways. Our MEASURE data set contains a diverse set of 11 targets with a wide range of periods, equilibrium temperatures and masses. For one of the targets, the Ultra Hot Jupiter WASP-33 b, we report the first detection of...
WASP-33b is an ultra hot Jupiter with a day-side temperature of 3100 K. In this talk, I will present our latest results in characterising its day-side atmosphere using the InfraRed Doppler instrument on the Subaru telescope. Using high-resolution cross-correlation spectroscopy, we confirmed our previous detection of OH emission but only after the secondary eclipse. Through an injection test,...
Context. Transmission spectroscopy is a prime technique to study the chemical composition and structure of exoplanetary atmospheres. Strong excess absorption signals have been detected in the optical Na I D1, 2 Fraunhofer lines during transits of hot Jupiters, which are attributed to the planetary atmospheres and allow us to constrain its structure.
Aims. We study the atmosphere of WASP-7 b...
Measuring the chemical and thermal properties of planetary atmospheres is the main goal of current exoplanet science. It allows us to understand their true nature, origin, and eventually the ability to support life. Ground-based, high-resolution spectroscopy (HRS, R>25,000) has emerged as one of the leading methods to detect atomic and molecular species in the atmospheres of exoplanets. At...
High-resolution Doppler-resolved spectroscopy has opened up a new window into the atmospheres of both transiting and non-transiting exoplanets. While the 'classical' cross-correlation approach is efficient for finding atomic and molecular species, it is quite limited with its inability to recover quantitative information on the atmosphere such as abundances and temperature profiles - the very...
The PEPSI Exoplanet Transit Survey (PETS) is a spectroscopic survey of exoplanet transits, secondary eclipses, and host-star characterization. In this collaborative effort from AIP, MPIA, INAF, University of Arizona, Ohio State University and the LBT, a large number of targets have been observed with the goal to characterize planetary atmospheres in detail.
Towards the atmospheric...
The class of hot terrestrial worlds known as lava planets has come under significant investigation in the last decade. The brightest and most well-studied of these objects is 55 Cancri e, a nearby super-Earth with a remarkable 17-hour orbit. However, despite numerous studies, debate remains about the existence and composition of its atmosphere. We present upper limits on the iron content of 55...
Just looking through a telescope from your backyard you can see that the planets from our own Solar-System have widely different atmospheres. Such a large diversity is also expected for exoplanets, particularly since they cover a much wider parameter space. Now that we are able to measure exoplanet atmospheric spectrum our goal is to separate the effects of intrinsic differences, such as...
High-resolution transmission spectroscopy is one of the most fruitful techniques to infer the main opacity sources, thermospheric temperature and evaporation processes in the atmosphere of transiting exoplanets. Before retrieving the planetary features, however, observed spectra must be corrected for sky emission, residual atmospheric dispersion, presence of telluric features and interstellar...
High resolution spectra of transit events enable the search for constituents in exoplanet atmospheres with a variety of methods.
Using cross correlation, the observations can be compared to models across a wide wavelength range, taking advantage of the large number of absorption lines of some species. For other species, the excess absorption in strong individual lines is measurable directly...
The next generation of ground-based telescopes, which complement the space missions, are aimed at HR (R ~ 100,000) studies. Ground-based high resolution Doppler spectroscopy (HRS), pioneered by Snellen, has been used to characterise the atmospheres of a growing number of exoplanets in recent years. None of this is possible without the necessary laboratory data. While spectroscopic and other...
It is only mildly controversial to insist that planets are three-dimensional. Whether or not 1D models can adequately be used to interpret exoplanet observations depends on some combination of how much spatial inhomogeneity exists on a planet and how sensitive the data are to its 3D structure. For atmospheric characterization using high resolution spectroscopy, our highest signal-to-noise...
Ultra-hot Jupiters are tidally locked gas giants with dayside temperatures high enough to dissociate hydrogen and other molecules. Featuring sharp chemical gradients and large temperature contrasts, their atmospheres are vastly non-uniform. In recent years, the wealth of data from high-resolution spectrographs such as HARPS-N, CRIRES, ESPRESSO and IGRINS has yielded spectacular insights into...
Exoplanet atmospheres are inherently three-dimensional systems in which thermal/chemical variation and winds can strongly influence spectra. Recently, the ultra-hot Jupiter WASP-76~b has shown evidence for condensation and asymmetric Fe absorption with time. However, it is unclear whether these asymmetries are driven by chemical or thermal differences between the two limbs, as precise...
We are developing an open-source auto–differentiable spectral modeling code "ExoJAX" to perform atmospheric retrieval for high-resolution exoplanetary spectra by ab initio spectral fitting. This enables fully Bayesian inference of atmospheric parameters with the Hamiltonian Monte Carlo. Meanwhile, the parameter estimation of M dwarfs, which are...
Ultrahot Jupiters are ideal candidates to explore with high-resolution emission spectra. Detailed theoretical studies are necessary to investigate the range of spectra we can expect to see from these objects throughout their orbit, because of the extreme temperature and chemical longitudinal gradients that exist across day and nightside regions. Using previously published 3D GCM models of...
High resolution spectroscopy is quickly establishing itself as one of the most exciting ground-based observational techniques for exoplanets. Especially the doppler shifts of atomic and molecular lines are an excellent probe of dynamics and thus offer a unique window into the atmospheres of exoplanets. This information is highly complementary when compared to space-based telescopes, which...
The evolution of planetary atmospheres is very much dependent on the environment of their host stars (e.g., stellar radiation, stellar wind, stellar flares and Coronal Mass Ejections (CMEs)). For close-in planets, the stellar radiation evaporates the planetary atmosphere as a form of supersonic planetary outflow due to photoionization. This planetary outflow further interacts with the stellar...
Spectrographs for radial velocities evolved from the specifications required for Galactic dynamics studies to those set by exoplanet mass characterization. As time went by, the search for lower-mass planets on longer periods pushed for higher measurement precision and improved instrument stability. But the detection of a transiting planet in 2000 and an exo-atmosphere in 2010 reshuffled...
We will discuss the results from the Exoplanets with Gemini Spectroscopy (ExoGemS) survey, which has acquired high-resolution transit spectroscopy of over a dozen exoplanets. Because our survey covers a large range of radii, masses, and Teq, we can compare how these properties affect the resulting transmission spectrum. The high-resolution of GRACES allows us to analyze the line profile and...
We aim to characterize transiting exoplanets spanning a wide range of sizes, masses and effective temperatures using a variety of high-resolution spectrographs, including through our on-going Gemini Large Program “Exploring the Diversity of Exoplanet Atmospheres at High Spectral Resolution” (ExoGemS, for short) with Gemini-N/GRACES. Here I will share a few early results from ExoGems, and...
Characterization of cooler atmospheres of super-Earths and Neptune sized objects at low-resolution is often thwarted by the presence of clouds, hazes and aerosols which effectively flatten the transmission spectra. High-Resolution Spectroscopy (HRS) presents an opportunity to overcome this limitation by having the ability to detect molecular species whose spectral line cores extend above the...
Directly imaged planets orbiting at very wide separation present a challenge to current planet formation theories. We present the analysis of new observations of beta Pictoris b with the refurbished and enhanced CRIRES+, with new constraints on its spin-rotation and C/O ratio. Furthermore, we will introduce a python package for the reduction of CRIRES+ data specifically aimed at directly...
I will discuss the smallsat SEEJ (Structure & Evolution of ExoJupiter Atmospheres). It will measure both the fluxes of high-energy photons emanating from a flux limited sample of planet-hosting stars and the absorption depth of X-rays in the atmospheres of hot Jupiter, Saturn, and Neptune analogs. SEEJ will measure how often high energy flares of a given size occur, and establish, for the...
The search for signs of life on other worlds is an exciting and now key component of exoplanet science. In the exoplanet context, biosignatures are potentially-detectable impacts of life on a global planetary environment. Biosignatures may include identified and sought after molecules in a planetary atmosphere, reflectivity signals on its surface, or the characteristic variation of these or...
The upcoming class of extremely large telescopes (ELTs) will provide an unprecedented opportunity to use high-resolution spectroscopy to characterize terrestrial exoplanets for habitability and life. In particular, these telescopes are likely the best near-term tools for detecting molecular oxygen in nearby exoplanet atmospheres. However, determining whether oxygen is more likely to have a...
Among more than 5000 exoplanets discovered up to now, around 60 are believed to be potentially habitable. The Sun-Earth system provides a unique example based on which detailed insights into the properties, formation, evolution, and thus habitability of exoplanets could be gained. However, observing the Sun as a star and the Earth as an exoplanet has been rare. In this talk, I will briefly...
The most common type of exoplanet discovered to date has a size that falls between Earth-sized and Neptune-sized, and orbits its star with a period less than 100 days. Atmospheric characterization of these planets often finds featureless transmission spectra, which is taken as evidence for the presence in the of clouds or hazes in the upper atmosphere that obscure the presence of deeper lying...
With advances in exoplanet detection, thousands exoplanets have been discovered including almost 200 confirmed rocky exoplanets. This leaves us with a large number of possible targets in the search for biomarkers. A quick look at our own solar system shows that not every planet can hold on to a significant or habitable atmosphere for an extended amount of time. Whether a planet can hold on to...
The upcoming Extremely Large Telescopes (ELTs) will have the collecting area required to detect potential biosignature gases such as molecular oxygen, O2, in the atmosphere of terrestrial planets around nearby stars. To maximize our capability to detect O2 using this method, extreme high spectral resolution R=300,000-500,000 is required to fully resolve the absorption lines in an exoplanet...
