The spin-rotation of a planet arises from the accretion of angular momentum during its Near-infrared high-dispersion spectroscopy has been used to characterize the atmospheres of hot Jupiters in close-in orbits [10][11] . Such observations utilize changes in the radial component of the orbital velocity of the planet (resulting in changes in Doppler shift) to filter out the quasi-stationary telluric and stellar contributions in the spectra. Here we make use of the spatial separation and the difference in spectral signature between the planet and star, which allow the starlight to be filtered out. A similar technique 12 has been applied very successfully 13 at a medium spectral dispersion to characterize the exoplanet HR8799c. We observed the β Pictoris system 7,8 (K=3.5) using the Cryogenic highResolution InfraRed Echelle Spectrograph CRIRES 14 located at the Nasmyth focus of UT1 of the Very Large Telescope (VLT) of the European Southern Observatory (ESO) at Cerro Paranal in Chile on the night of 17 December 2013, with the slit oriented in such way that it encompassed the planet and star.An important step in the data analysis is the optimal removal of the stellar contribution along the slit, which for this A-star consists mostly of a telluric absorption spectrum. The resulting spectra were cross-correlated with theoretical spectral templates constructed in a similar way as in our previous work on hot Jupiters 10-11 , varying the planet's atmospheric temperature pressure (T/p) profile, the carbon monoxide abundance and that of water vapor and methane, which can also show features in the observed wavelength range. Note that there is a strong degeneracy between the atmospheric T/p profile and the abundance of the molecular species, meaning that different combinations of these parameters result in nearly identical template spectra.At the expected planet position a broad and blue-shifted signal is apparent (see Figure 1), which is strongest when the cross-correlation is performed with a spectral template from an atmospheric model with deep carbon monoxide lines and a small contribution from water. We estimate the signal to have a SNR of 6.4 by cross-correlating the residual spectrum with a broadened model template, and compare the peak of the cross-correlation profile with the standard deviation. If we use the crosscorrelation profile as seen in Figure 1 to estimate the SNR, we need to take into account the width of the signal and the dependence of adjacent pixels in the profile. This results in an SNR of 7.8, but this latter method we found to be less accurate, since it does not properly include contributions from correlated noise structures on scales of the broad signal. Cross-correlation with the optimal spectrum of water vapor alone provides a marginal signal at SNR~2, which means we cannot claim a firm detection of water in the planet atmosphere. No signal is retrieved for methane models (see Extended Data Fig. 1).We fit the planet profile using a grid of artificial cross-correlation functions, produced by crossc...

Giant exoplanets orbiting very close to their parent star (hot Jupiters) are subject to tidal forces expected to synchronize their rotational and orbital periods on short timescales (tidal locking). However, spin rotation has never been measured directly for hot Jupiters. Furthermore, their atmospheres can show equatorial super-rotation via strong eastward jet streams, and/or high-altitude winds flowing from the day-to the night-side hemisphere. Planet rotation and atmospheric circulation broaden and distort the planet spectral lines to an extent that is detectable with measurements at high spectral resolution. We observed a transit of the hot Jupiter HD 189733 b around 2.3 µm and at a spectral resolution of R ∼ 10 5 with CRIRES at the ESO Very Large Telescope. After correcting for the stellar absorption lines and their distortion during transit (the Rossiter-McLaughlin effect), we detect the absorption of carbon monoxide and water vapor in the planet transmission spectrum by cross-correlating with model spectra. The signal is maximized (7.6σ) for a planet rotational velocity of (3.4 +1.3 −2.1 ) km s −1 , corresponding to a rotational period of (1.7 +2.9 −0.4 ) days. This is consistent with the planet orbital period of 2.2 days and therefore with tidal locking. We find that the rotation of HD 189733 b is longer than 1 day (3σ). The data only marginally (1.5σ) prefer models with rotation versus models without rotation. We measure a small day-to night-side wind speed of (−1.7 +1.1 −1.2 ) km s −1 . Compared to the recent detection of sodium blue-shifted by (8 ± 2) km s −1 , this likely implies a strong vertical wind shear between the pressures probed by near-infrared and optical transmission spectroscopy.

We report a 4.8σ detection of water absorption features in the day side spectrum of the hot Jupiter HD 189733 b. We used high-resolution (R ∼ 100 000) spectra taken at 3.2 µm with CRIRES on the VLT to trace the radial-velocity shift of the water features in the planet's day side atmosphere during 5 h of its 2.2 d orbit as it approached secondary eclipse. Despite considerable telluric contamination in this wavelength regime, we detect the signal within our uncertainties at the expected combination of systemic velocity (V sys = −3 +5 −6 km s −1 ) and planet orbital velocity (K p = 154 +14 −10 km s −1 ), and determine a H 2 O line contrast ratio of (1.3 ± 0.2) × 10 −3 with respect to the stellar continuum. We find no evidence of significant absorption or emission from other carbon-bearing molecules, such as methane, although we do note a marginal increase in the significance of our detection to 5.1σ with the inclusion of carbon dioxide in our template spectrum. This result demonstrates that ground-based, highresolution spectroscopy is suited to finding not just simple molecules like CO, but also to more complex molecules like H 2 O even in highly telluric contaminated regions of the Earth's transmission spectrum. It is a powerful tool that can be used for conducting an immediate census of the carbon-and oxygen-bearing molecules in the atmospheres of giant planets, and will potentially allow the formation and migration history of these planets to be constrained by the measurement of their atmospheric C/O ratios.

Context. Ground-based high-dispersion (R ∼ 100 000) spectroscopy (HDS) is proving to be a powerful technique with which to characterize extrasolar planets. The planet signal is distilled from the bright starlight, combining ral and time-differential filtering techniques. In parallel, high-contrast imaging (HCI) is developing rapidly, aimed at spatially separating the planet from the star. While HDS is limited by the overwhelming noise from the host star, HCI is limited by residual quasi-static speckles. Both techniques currently reach planet-star contrast limits down to ∼10 −5 , albeit for very different types of planetary systems. Aims. In this work, we discuss a way to combine HDS and HCI (HDS+HCI). For a planet located at a resolvable angular distance from its host star, the starlight can be reduced up to several orders of magnitude using adaptive optics and/or coronography. In addition, the remaining starlight can be filtered out using high-dispersion spectroscopy, utilizing the significantly different (or Doppler shifted) high-dispersion spectra of the planet and star. In this way, HDS+HCI can in principle reach contrast limits of ∼10 −5 ×10 −5 , although in practice this will be limited by photon noise and/or sky-background. In contrast to current direct imaging techniques, such as Angular Differential Imaging and Spectral Differential Imaging, it will work well at small working angles and is much less sensitive to speckle noise. For the discovery of previously unknown planets HDS+HCI requires a high-contrast adaptive optics system combined with a high-dispersion R ∼ 100 000 integral field spectrograph (IFS). This combination currently does not exist, but is planned for the European Extremely Large Telescope. Methods. We present simulations of HDS+HCI observations with the E-ELT, both probing thermal emission from a planet at infrared wavelengths, and starlight reflected off a planet atmosphere at optical wavelengths. For the infrared simulations we use the baseline parameters of the E-ELT and METIS instrument, with the latter combining extreme adaptive optics with an R = 100 000 IFS. We include realistic models of the adaptive optics performance and atmospheric transmission and emission. For the optical simulation we also assume R = 100 000 IFS with adaptive optics capabilities at the E-ELT. Results. One night of HDS+HCI observations with the E-ELT at 4.8 μm (Δλ = 0.07 μm) can detect a planet orbiting α Cen A with a radius of R = 1.5 R earth and a twin-Earth thermal spectrum of T eq = 300 K at a signal-to-noise (S/N) of 5. In the optical, with a Strehl ratio performance of 0.3, reflected light from an Earth-size planet in the habitable zone of Proxima Centauri can be detected at a S/N of 10 in the same time frame. Recently, first HDS+HCI observations have shown the potential of this technique by determining the spin-rotation of the young massive exoplanet β Pictoris b. Conclusions. The exploration of the planetary systems of our neighbor stars is of great scientific and philosophical value. The HD...

We report the detection of water absorption features in the day side spectrum of the first-known hot Jupiter, 51 Peg b, confirming the star-planet system to be a double-lined spectroscopic binary. We use high-resolution ( » R 100,000), m 3.2 m spectra taken with CRIRES/VLT to trace the radial-velocity shift of the water features in the planet's day side atmosphere during 4 hr of its 4.23 day orbit after superior conjunction. We detect the signature of molecular absorption by water at a significance of J , placing it at the transition boundary between Jovian and Neptunian worlds. We determine upper and lower limits on the orbital inclination of the system of  < <  i 70 8 2.2. We also provide an updated orbital solution for 51 Peg b, using an extensive set of 639 stellar radial velocities measured between 1994 and 2013, finding no significant evidence of an eccentric orbit. We find no evidence of significant absorption or emission from other major carbon-bearing molecules of the planet, including methane and carbon dioxide. The atmosphere is non-inverted in the temperature-pressure region probed by these observations. The deepest absorption lines reach an observed relative contrast of´-0.9 10 3 with respect to the host star continuum flux at an angular separation of 3 milliarcseconds. This work is consistent with a previous tentative report of K-band molecular absorption for 51 Peg b by Brogi et al.