scholarly journals HST/STIS transmission spectrum of the ultra-hot Jupiter WASP-76 b confirms the presence of sodium in its atmosphere

2020 ◽  
Vol 637 ◽  
pp. A76 ◽  
Author(s):  
C. von Essen ◽  
M. Mallonn ◽  
S. Hermansen ◽  
M. C. Nixon ◽  
N. Madhusudhan ◽  
...  
Keyword(s):  
High Resolution ◽  
Transmission Spectrum ◽  
Rayleigh Scattering ◽  
Equilibrium Temperature ◽  
Atmospheric Transmission ◽  
Space Telescope ◽  
Atomic Sodium ◽  
The One ◽  
Imaging Spectrograph ◽  
Hot Jupiter

We present an atmospheric transmission spectrum of the ultra-hot Jupiter WASP-76 b by analyzing archival data obtained with the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST). The dataset spans three transits, two with a wavelength coverage between 2900 and 5700 Å, and the third one between 5250 and 10 300 Å. From the one-dimensional, time dependent spectra we constructed white and chromatic light curves, the latter with typical integration band widths of ~200 Å. We computed the wavelength dependent planet-to-star radii ratios taking into consideration WASP-76’s companion. The resulting transmission spectrum of WASP-76 b is dominated by a spectral slope of increasing opacity towards shorter wavelengths of amplitude of about three scale heights under the assumption of planetary equilibrium temperature. If the slope is caused by Rayleigh scattering, we derive a lower limit to the temperature of ~870 K. Following-up on previous detection of atomic sodium derived from high resolution spectra, we re-analyzed HST data using narrower bands centered around sodium. From an atmospheric retrieval of this transmission spectrum, we report evidence of sodium at 2.9σ significance. In this case, the retrieved temperature at the top of the atmosphere (10−5 bar) is 2300−392+412 K. We also find marginal evidence for titanium hydride. However, additional high resolution ground-based data are required to confirm this discovery.

scholarly journals The Hubble PanCET program: Transit and Eclipse Spectroscopy of the Hot-Jupiter WASP-74b

2021 ◽  
Vol 162 (6) ◽  
pp. 271
Author(s):  
Guangwei Fu ◽  
Drake Deming ◽  
Erin May ◽  
Kevin Stevenson ◽  
David K. Sing ◽  
...  
Keyword(s):  
Rayleigh Scattering ◽  
Hubble Space Telescope ◽  
Absorption Feature ◽  
Spectral Library ◽  
Data Set ◽  
Space Telescope ◽  
Methane Absorption ◽  
James Webb Space Telescope ◽  
Hot Jupiter

Abstract Planets are like children with each one being unique and special. A better understanding of their collective properties requires a deeper understanding of each planet. Here we add the transit and eclipse spectra of hot-Jupiter WASP-74b into the ever growing data set of exoplanet atmosphere spectral library. With six transits and three eclipses using the Hubble Space Telescope and Spitzer Space Telescope (Spitzer), we present the most complete and precise atmospheric spectra of WASP-74b. We found no evidence for TiO/VO nor super-Rayleigh scattering reported in previous studies. The transit shows a muted water feature with strong Rayleigh scattering extending into the infrared. The eclipse shows a featureless blackbody-like WFC3/G141 spectrum and a weak methane absorption feature in the Spitzer 3.6 μm band. Future James Webb Space Telescope follow-up observations are needed to confirm these results.

scholarly journals MASCARA-4 b/bRing-1 b: A retrograde hot Jupiter around a bright A-type star

2020 ◽  
Vol 635 ◽  
pp. A60 ◽  
Author(s):  
P. Dorval ◽  
G. J. J. Talens ◽  
G. P. P. L. Otten ◽  
R. Brahm ◽  
A. Jordán ◽  
...  
Keyword(s):  
High Resolution ◽  
Absolute Magnitude ◽  
Equilibrium Temperature ◽  
Least Square ◽  
Data Sets ◽  
Wide Field ◽  
Retrograde Orbit ◽  
High Resolution Spectrometer ◽  
M Dwarf ◽  
Hot Jupiter

Context. The Multi-site All-Sky CAmeRA (MASCARA) and bRing are both photometric ground-based instruments with multiple stations that rely on interline charge-coupled devices with wide-field lenses to monitor bright stars in the local sky for variability. MASCARA has already discovered several planets in the northern sky, which are among the brightest known transiting hot Jupiter systems. Aims. In this paper, we aim to characterize a transiting planetary candidate in the southern skies found in the combined MASCARA and bRing data sets of HD 85628, an A7V star of V = 8.2 mag at a distance 172 pc, to establish its planetary nature. Methods. The candidate was originally detected in data obtained jointly with the MASCARA and bRing instruments using a Box Least-Square search for transit events. Further photometry was taken by the 0.7 m Chilean-Hungarian Automated Telescope (CHAT), and radial velocity measurements with the Fiber Dual Echelle Optical Spectrograph on the European Southern Observatory 1.0 m Telescope. High-resolution spectra during a transit were taken with the CTIO high-resolution spectrometer (CHIRON) on the Small and Moderate Aperture Research Telescope System 1.5 m telescope to target the Doppler shadow of the candidate. Results. We confirm the existence of a hot Jupiter transiting the bright A7V star HD 85628, which we co-designate as MASCARA-4b and bRing-1b. It is in an orbit of 2.824 days, with an estimated planet radius of 1.53−0.04+0.07 RJup and an estimated planet mass of 3.1 ± 0.9 MJup, putting it well within the planetary regime. The CHAT observations show a partial transit, reducing the probability that the transit was around a faint background star. The CHIRON observations show a clear Doppler shadow, implying that the transiting object is in a retrograde orbit with |λ| =244.9−3.6+2.7°. The planet orbits at a distance of 0.047 ± 0.004 AU from the star and has a zero-albedo equilibrium temperature of 2100 ± 100 K. In addition, we find that HD 85628 has a previously unreported stellar companion star in the Gaia DR2 data demonstrating common proper motion and parallax at 4.3′′ separation (projected separation ~740 AU), and with absolute magnitude consistent with being a K/M dwarf. Conclusions. MASCARA-4 b/bRing-1 b is the brightest transiting hot Jupiter known to date in a retrograde orbit. It further confirms that planets in near-polar and retrograde orbits are more common around early-type stars. Due to its high apparent brightness and short orbital period, the system is particularly well suited for further atmospheric characterization.

scholarly journals High-resolution transmission spectrum of the Earth's atmosphere-seeing Earth as an exoplanet using a lunar eclipse

2014 ◽  
Vol 14 (2) ◽  
pp. 255-266 ◽  
Author(s):  
F. Yan ◽  
R. A. E. Fosbury ◽  
M. G. Petr-Gotzens ◽  
G. Zhao ◽  
W. Wang ◽  
...  
Keyword(s):  
High Resolution ◽  
Water Vapour ◽  
Transmission Spectrum ◽  
Atmospheric Model ◽  
High Signal ◽  
Absorption Feature ◽  
Lunar Eclipse ◽  
Atmospheric Transmission ◽  
Earth’S Atmosphere ◽  
Earth's Atmosphere

AbstractWith the rapid developments in the exoplanet field, more and more terrestrial exoplanets are being detected. Characterizing their atmospheres using transit observations will become a key datum in the quest for detecting an Earth-like exoplanet. The atmospheric transmission spectrum of our Earth will be an ideal template for comparison with future exo-Earth candidates. By observing a lunar eclipse, which offers a similar configuration to that of an exoplanet transit, we have obtained a high-resolution and high signal-to-noise ratio (SNR) transmission spectrum of the Earth's atmosphere. This observation was performed with the High Resolution Spectrograph at Xinglong Station, China during the total lunar eclipse in December 2011. We compare the observed transmission spectrum with our atmospheric model, and determine the characteristics of the various atmospheric species in detail. In the transmission spectrum, O2, O3, O2 · O2, NO2 and H2O are detected, and their column densities are measured and compared with the satellites data. The visible Chappuis band of ozone produces the most prominent absorption feature, which suggests that ozone is a promising molecule for the future exo-Earth characterization. Due to the high resolution and high SNR of our spectrum, several novel details of the Earth atmosphere's transmission spectrum are presented. The individual O2 lines are resolved and O2 isotopes are clearly detected. Our new observations do not confirm the absorption features of Ca II or Na I which have been reported in previous lunar eclipse observations. However, features in these and some other strong Fraunhofer line positions do occur in the observed spectrum. We propose that these are due to a Raman-scattered component in the forward-scattered sunlight appearing in the lunar umbral spectrum. Water vapour absorption is found to be rather weak in our spectrum because the atmosphere we probed is relatively dry, which prompts us to discuss the detectability of water vapour in Earth-like exoplanet atmospheres.

scholarly journals Detection of Na, K, and Hα absorption in the atmosphere of WASP-52b using ESPRESSO

2020 ◽  
Vol 635 ◽  
pp. A171 ◽  
Author(s):  
G. Chen ◽  
N. Casasayas-Barris ◽  
E. Pallé ◽  
F. Yan ◽  
M. Stangret ◽  
...  
Keyword(s):  
High Resolution ◽  
Transmission Spectrum ◽  
Orbital Motion ◽  
Telescope Array ◽  
Hot Jupiters ◽  
Velocity Shift ◽  
Very Large Telescope ◽  
Cloudy Atmosphere ◽  
Excess Absorption ◽  
Hot Jupiter

WASP-52b is a low-density hot Jupiter orbiting a moderately active K2V star. Previous low-resolution studies have revealed a cloudy atmosphere and found atomic Na above the cloud deck. Here we report on the detection of excess absorption at the Na doublet, the Hα line, and the K D1 line. We derived a high-resolution transmission spectrum based on three transits of WASP-52b, observed with the ultra-stable, high-resolution spectrograph ESPRESSO at the Very Large Telescope array. We measured a line contrast of 1.09 ± 0.16% for Na D1, 1.31 ± 0.13% for Na D2, 0.86 ± 0.13% for Hα, and 0.46 ± 0.13% for K D1, with a line FWHM range of 11–22 km s−1. We also found that the velocity shift of these detected lines during the transit is consistent with the planet’s orbital motion, thus confirming their planetary origin. We did not observe any significant net blueshift or redshift that could be attributed to planetary winds. We used activity indicator lines as control but found no excess absorption. However, we did notice signatures arising from the Center-to-Limb variation (CLV) and the Rossiter-McLaughlin (RM) effect at these control lines. This highlights the importance of the CLV + RM correction in correctly deriving the transmission spectrum, which, if not corrected, could resemble or cancel out planetary absorption in certain cases. WASP-52b is the second non-ultra-hot Jupiter to show excess Hα absorption after HD 189733b. Future observations targeting non-ultra-hot Jupiters that show Hα could help reveal the relation between stellar activity and the heating processes in the planetary upper atmosphere.

scholarly journals STIS Coronagraphic Observations of β Pictoris

2004 ◽  
Vol 202 ◽  
pp. 338-340
Author(s):  
S. R. Heap ◽  
D. J. Lindler ◽  
T. M. Lanz
Keyword(s):  
High Resolution ◽  
Spectral Region ◽  
Hubble Space Telescope ◽  
Space Telescope ◽  
High Resolution Images ◽  
Imaging Spectrograph

We present recent coronagraphic observations of β Pictoris obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope. The superb, high-resolution images show that the inner part of the disk is inclined by about 5° with respect to the main disk. Long-slit coronagraphic spectrograms oriented along the inner disk indicate that the reflectance of the inner disk is neutral over the spectral region, 3000-5600 Å.

scholarly journals An Optical Transmission Spectrum for the Ultra-hot Jupiter WASP-121b Measured with the Hubble Space Telescope

2018 ◽  
Vol 156 (6) ◽  
pp. 283 ◽  
Author(s):  
Thomas M. Evans ◽  
David K. Sing ◽  
Jayesh M. Goyal ◽  
Nikolay Nikolov ◽  
Mark S. Marley ◽  
...  
Keyword(s):  
Transmission Spectrum ◽  
Optical Transmission ◽  
Hubble Space Telescope ◽  
Optical Transmission Spectrum ◽  
Space Telescope ◽  
Hot Jupiter

scholarly journals The D/H Ratio in Interstellar Gas toward the Hot, White Dwarf G191-B2B

2000 ◽  
Vol 198 ◽  
pp. 161-166
Author(s):  
M. S. Sahu
Keyword(s):  
High Resolution ◽  
White Dwarf ◽  
New Work ◽  
Interstellar Gas ◽  
Space Telescope ◽  
Imaging Spectrograph

Space Telescope Imaging Spectrograph (STIS) observations of the D/H ratio in the two velocity components towards G191-B2B are consistent with 1.5 ± 0.1 × 10−5 and do not agree with the values derived using the Goddard High Resolution Spectrograph (GHRS) data. We present some new work on the G191-B2B sightline, and the results we obtain are consistent with those of Sahu et al. (1999).

scholarly journals Ground-based transmission spectroscopy with FORS2: A featureless optical transmission spectrum and detection of H2O for the ultra-hot Jupiter WASP-103b

2020 ◽  
Vol 497 (4) ◽  
pp. 5155-5170 ◽  
Author(s):  
Jamie Wilson ◽  
Neale P Gibson ◽  
Nikolay Nikolov ◽  
Savvas Constantinou ◽  
Nikku Madhusudhan ◽  
...  
Keyword(s):  
Transmission Spectrum ◽  
Rayleigh Scattering ◽  
Full Range ◽  
Broad Band ◽  
Light Curves ◽  
Small Scale ◽  
Correlated Noise ◽  
Transmission Spectroscopy ◽  
Short Period ◽  
Hot Jupiter

ABSTRACT We report ground-based transmission spectroscopy of the highly irradiated and ultra-short period hot-Jupiter WASP-103b covering the wavelength range ≈400–600 nm using the FORS2 instrument on the Very Large Telescope. The light curves show significant time-correlated noise which is mainly invariant in wavelength and which we model using a Gaussian process. The precision of our transmission spectrum is improved by applying a common-mode correction derived from the white light curve, reaching typical uncertainties in transit depth of ≈2 × 10−4 in wavelength bins of 15 nm. After correction for flux contamination from a blended companion star, our observations reveal a featureless spectrum across the full range of the FORS2 observations and we are unable to confirm the Na absorption previously inferred using Gemini/GMOS or the strong Rayleigh scattering observed using broad-band light curves. We performed a Bayesian atmospheric retrieval on the full optical-infrared transmission spectrum using the additional data from Gemini/GMOS, HST/WFC3, and Spitzer observations and recover evidence for H2O absorption at the 4.0 σ level. However, our observations are not able to completely rule out the presence of Na, which is found at 2.0 σ in our retrievals. This may in part be explained by patchy/inhomogeneous clouds or hazes damping any absorption features in our FORS2 spectrum, but an inherently small scale height also makes this feature challenging to probe from the ground. Our results none the less demonstrate the continuing potential of ground-based observations for investigating exoplanet atmospheres and emphasize the need for the application of consistent and robust statistical techniques to low-resolution spectra in the presence of instrumental systematics.

scholarly journals Spectral signature of atmospheric winds in high-resolution transit observations

2021 ◽  
Vol 502 (1) ◽  
pp. 1456-1468
Author(s):  
Engin Keles
Keyword(s):  
High Resolution ◽  
Equilibrium Temperature ◽  
Absorption Lines ◽  
Spectral Signature ◽  
Jet Streams ◽  
Hot Jupiters ◽  
Spatially Resolved ◽  
Wind Velocities ◽  
Good Tracer ◽  
Hot Jupiter

ABSTRACT The study of exoplanet atmospheres showed large diversity compared to the planets in our Solar system. Especially Jupiter-type exoplanets orbiting their host star in close orbits, the so-called hot and ultra-hot Jupiters, have been studied in detail due to their enhanced atmospheric signature. Due to their tidally locked status, the temperature difference between the day- and nightside triggers atmospheric winds that can lead to various fingerprints in the observations. Spatially resolved absorption lines during transit such as sodium (Na) could be a good tracer for such winds. Different works resolved the Na absorption lines on different exoplanets which show different line widths. Assuming that this could be attributed to such zonal jet streams, this work models the effect of such winds on synthetic absorption lines. For this, transiting Jupiter-type planets with rotational velocities similar to hot and ultra-hot Jupiter are considered. The investigation shows that high wind velocities could reproduce the broadening of Na-line profiles inferred in different high-resolution transit observations. There is a tendency that the broadening values decrease for planets with lower equilibrium temperature. This could be explained by atmospheric drag induced by the ionization of alkali lines that slow down the zonal jet streams, favouring their existence on hot Jupiter rather than ultra-hot Jupiter.

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