ABSTRACT
The discovery of a population of close-orbiting giant planets (≤ 1 au) has raised a number of questions about their origins and dynamical histories. These issues have still not been fully ...resolved, despite over 20 years of exoplanet detections and a large number of discovered exoplanets. In particular, it is unclear whether warm Jupiters (WJs) form in situ, or whether they migrate from further outside and are even currently migrating to form hot Jupiters. Here, we report the possible discovery and characterization of the planets in a highly mutually inclined (Imut ≃ 45°) compact two-planet system (KOI-984), in which the newly discovered warm Jupiter KOI-984c is on a 21.5-d moderately eccentric (e ≃ 0.4) orbit, in addition to a previously known 4.3-d planet candidate KOI-984b. Meanwhile, the orbital configuration of a moderately inclined (Imut ≃ 15°) low-mass (mc ≃ 24M⊕; Pb ≃ 8.6 d) perturbing planet near the 1:2 mean-motion resonance with KOI-984b could also well reproduce the observed transit-timing variations and transit-duration variations of KOI-984b. Such an eccentric WJ with a close-in sibling would pose a challenge to the proposed formation and migration mechanisms of WJs if the first scenario is supported with more evidence in the near future; this system with several other well measured inclined WJ systems (e.g. Kepler-419 and Kepler-108) may provide additional clues to the origin and dynamical histories of WJs.
Accurately estimating the C/O ratio of hot Jupiter atmospheres is a promising pathway towards understanding planet formation and migration, as well as the formation of clouds and the overall ...atmospheric composition. The atmosphere of the hot Jupiter WASP-43b has been extensively analysed using low-resolution observations with HST and
Spitzer,
but these previous observations did not cover the K band, which hosts prominent spectral features of major carbon-bearing species such as CO and CH
4
. As a result, the ability to establish precise constraints on the C/O ratio was limited. Moreover, the planet has not been studied at high spectral resolution, which can provide insights into the atmospheric dynamics. In this study, we present the first high-resolution dayside spectra of WASP-43b with the new CRIRES
+
spectrograph. By observing the planet in the K band, we successfully detected the presence of CO and provide evidence for the existence of H
2
O using the cross-correlation method. This discovery represents the first direct detection of CO in the atmosphere of WASP-43b. Furthermore, we retrieved the temperature-pressure profile, abundances of CO and H
2
O, and a super-solar C/O ratio of 0.78 by applying a Bayesian retrieval framework to the data. Our findings also shed light on the atmospheric characteristics of WASP-43b. We found no evidence for a cloud deck on the dayside, and recovered a line broadening indicative of an equatorial super-rotation corresponding to a jet with a wind speed of ~5kms
−1
, matching the results of previous forward models and low-resolution atmospheric retrievals for this planet.
Consideration of both low- and high-resolution transmission spectroscopy is key for obtaining a comprehensive picture of exoplanet atmospheres. In studies of transmission spectra, the continuum ...information is well established with low-resolution spectra, while the shapes of individual lines are best constrained with high-resolution observations. In this work, we aim to merge high- with low-resolution transmission spectroscopy to place tighter constraints on physical parameters of the atmospheres. We present the analysis of three primary transits of WASP-69 b in the visible (VIS) channel of the CARMENES instrument and perform a combined low- and high-resolution analysis using additional data from HARPS-N, OSIRIS/GTC, and WFC3/HST already available in the literature. We investigate the Na
I
D
1
and D
2
doublet, H
α
, the Ca
II
infra-red triplet (IRT), and K
I
λ
7699 Å lines, and we monitor the stellar photometric variability by performing long-term photometric observations with the STELLA telescope. During the first CARMENES observing night, we detected the planet Na
I
D
2
and D
1
lines at ~7 and ~3
σ
significance levels, respectively. We measured a D
2
/D
1
intensity ratio of 2.5 ± 0.7, which is in agreement with previous HARPS-N observations. Our modelling of WFC3 and OSIRIS data suggests strong Rayleigh scattering, solar to super-solar water abundance, and a highly muted Na feature in the atmosphere of this planet, in agreement with previous investigations of this target. We use the continuum information retrieved from the low-resolution spectroscopy as a prior to break the degeneracy between the Na abundance, reference pressure, and thermosphere temperature for the high-resolution spectroscopic analysis. We fit the Na
I
D
1
and D
2
lines individually and find that the posterior distributions of the model parameters agree with each other within 1
σ
. Our results suggest that local thermodynamic equilibrium processes can explain the observed D
2
/D
1
ratio because the presence of haze opacity mutes the absorption features.
Atmospheres of highly irradiated gas giant planets host a large variety of atomic and ionic species. Here we observe the thermal emission spectra of the two ultra-hot Jupiters WASP-33b and ...KELT-20b/MASCARA-2b in the near-infrared wavelength range with CARMENES. Via high-resolution Doppler spectroscopy, we searched for neutral silicon (Si) in their dayside atmospheres. We detect the Si spectral signature of both planets via cross-correlation with model spectra. Detection levels of 4.8
σ
and 5.4
σ
, respectively, are observed when assuming a solar atmospheric composition. This is the first detection of Si in exoplanet atmospheres. The presence of Si is an important finding due to its fundamental role in cloud formation and, hence, for the planetary energy balance. Since the spectral lines are detected in emission, our results also confirm the presence of an inverted temperature profile in the dayside atmospheres of both planets.
Ultrahot Jupiters are a type of gaseous exoplanet that orbit extremely close to their host star, resulting in significantly high equilibrium temperatures. In recent years, high-resolution emission ...spectroscopy has been broadly employed in observing the atmospheres of ultrahot Jupiters. We used the CARMENES spectrograph to observe the high-resolution spectra of the dayside hemisphere of MASCARA-1b in both visible and near-infrared. Through cross-correlation analysis, we detected signals of Fe I and Ti I . Based on these detections, we conducted an atmospheric retrieval and discovered the presence of a strong inversion layer in the planet’s atmosphere. The retrieved Ti and Fe abundances are broadly consistent with solar abundances. In particular, we obtained a relative abundance of Ti/Fe as −1.0 ± 0.8 under the free retrieval and −0.4 −0.8 +0.5 under the chemical equilibrium retrieval, suggesting the absence of significant titanium depletion on this planet. Furthermore, we considered the influence of planetary rotation on spectral line profiles. The resulting equatorial rotation speed was determined to be 4.4 −2.0 +1.6 km s −1 , which agrees with the rotation speed induced by tidal locking.
ABSTRACT Absorption lines from exoplanet atmospheres observed in transmission allow us to study atmospheric characteristics such as winds. We present a new high-resolution transit time-series of HD ...189733b, acquired with the PEPSI instrument at the LBT and analyse the transmission spectrum around the Na d lines. We model the spectral signature of the RM-CLV-effect using synthetic PHOENIX spectra based on spherical LTE atmospheric models. We find an Na d absorption signature between the second and third contact but not during the ingress and egress phases, which casts doubt on the planetary origin of the signal. Presupposing a planetary origin of the signal, the results suggest a weak day-to-nightside streaming wind in the order of 0.7 km s−1 and a moderate super-rotational streaming wind in the order of 3–4 km s−1, challenging claims of prevailing strong winds on HD 189733b.
Context.
Relatively large radii of some hot Jupiters observed in the ultraviolet and blue-optical are generally interpreted to be due to Rayleigh scattering by high-altitude haze particles. However, ...the haze composition and its production mechanisms are not fully understood, and observational information is still limited.
Aims.
We aim to study the presence of hazes in the atmospheres of HD 209458 b and HD 189733 b with high spectral resolution spectra by analysing the strength of water vapour cross-correlation signals across the red optical and near-infrared wavelength ranges.
Methods.
A total of seven transits of the two planets were observed with the CARMENES spectrograph at the 3.5 m Calar Alto telescope. Their Doppler-shifted signals were disentangled from the telluric and stellar contributions using the detrending algorithm
SYSREM
. The residual spectra were subsequently cross-correlated with water vapour templates at 0.70–0.96
μ
m to measure the strength of the water vapour absorption bands.
Results.
The optical water vapour bands were detected at 5.2
σ
in HD 209458 b in one transit, whereas no evidence of them was found in four transits of HD 189733 b. Therefore, the relative strength of the optical water bands compared to those in the near-infrared were found to be larger in HD 209458 b than in HD 189733 b.
Conclusions.
We interpret the non-detection of optical water bands in the transmission spectra of HD 189733 b, compared to the detection in HD 209458 b, to be due to the presence of high-altitude hazes in the former planet, which are largely absent in the latter. This is consistent with previous measurements with the
Hubble
Space Telescope. We show that currently available CARMENES observations of hot Jupiters can be used to investigate the presence of haze extinction in their atmospheres.
Most physical data sets contain a stochastic contribution produced by measurement noise or other random sources along with the signal. Usually, neither the signal nor the noise are accurately known ...prior to the measurement so that both have to be estimated a posteriori. We have studied a procedure to estimate the standard deviation of the stochastic contribution assuming normality and independence, requiring a sufficiently well-sampled data set to yield reliable results. This procedure is based on estimating the standard deviation in a sample of weighted sums of arbitrarily sampled data points and is identical to the so-called DER_SNR algorithm for specific parameter settings. To demonstrate the applicability of our procedure, we present applications to synthetic data, high-resolution spectra, and a large sample of space-based light curves and, finally, give guidelines to apply the procedure in situation not explicitly considered here to promote its adoption in data analysis.
HD 209458 is one of the benchmark objects in the study of hot Jupiter atmospheres and their evaporation through planetary winds. The expansion of the planetary atmosphere is thought to be driven by ...high-energy extreme ultraviolet (EUV) and X-ray irradiation. We obtained new Chandra High Resolution Camera (HRC-I) data, which unequivocally show that HD 209458 is an X-ray source. Combining these data with archival XMM-Newton observations, we find that the corona of HD 209458 is characterized by a temperature of about 1 MK and an emission measure of 7 × 1049 cm-3, yielding an X-ray luminosity of 1.6 × 1027 erg s-1 in the 0.124−2.48 keV band. HD 209458 is an inactive star that has a coronal temperature comparable to that of the inactive Sun but that has a larger emission measure. At this level of activity, the planetary high-energy emission is sufficient to support mass loss at a rate of a few times 1010 g s-1.
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