The technique of transmission spectroscopy allows us to constrain the chemical composition of the atmospheres of transiting exoplanets. It relies on very high signal-to-noise spectroscopic (or ...spectrophotometric) observations and is thus most suited for bright exoplanet host stars. In the era of the Transiting Exoplanet Survey Satellite, Next Generation Space Telescope, and PLAnetary Transits and Oscillations of stars (PLATO), more and more suitable targets, even for mid-sized telescopes, are discovered. Furthermore, a wealth of archival data is available that could become a basis for long-term monitoring of exo-atmospheres. We analyzed archival High Accuracy Radial velocity Planet Searcher (HARPS) spectroscopic time series of four host stars to transiting bloated gas exoplanets, namely WASP-76b, WASP-127b, WASP-166b, and KELT-11b, searching for traces of sodium (sodium doublet), hydrogen (H , Hβ), and lithium (670.8 nm). The archival data sets include spectroscopic time series taken during transits. Comparing in- and out-of-transit spectra we can filter out the stellar lines and investigate the absorption from the planet. Simultaneously, the stellar activity is monitored using the Mg i and Ca i lines. We detect sodium in the atmosphere of WASP-76b at a 7-9 level. Furthermore, we report also at a 4-8 level of significance the detection of sodium in the atmosphere of WASP-127b, confirming earlier results based on low-resolution spectroscopy. The data show no sodium nor any other atom at high confidence levels for WASP-166b nor KELT-11b, hinting at the presence of thick high clouds.
Context.
Our knowledge of populations and the occurrence of planets orbiting evolved intermediate-mass stars is still incomplete. In 2010 we started a planet search programme among 95 giant stars ...observed by the
Kepler
mission to increase the sample of giant stars with planets and with reliable estimates of stellar masses and radii.
Aims.
We present the two systems from our planet search programme whose companions we were able to characterise: KIC 3526061 and HD 187878.
Methods.
We used precise stellar radial velocity measurements taken with four different echelle spectrographs to derive an orbital solution. We used
Gaia
astrometric measurements to obtain the inclination of the HD 187878 system and
Kepler
photometric observations to estimate the stellar mass and radius.
Results.
We report the discovery of a sub-stellar companion and a stellar companion around two intermediate-mass red giant branch stars. KIC 3526061 b is most likely a brown dwarf with a minimum mass of 18.15 ± 0.44
M
Jupiter
in a long-period eccentric orbit, with orbital period 3552
−135
+158
d and orbital eccentricity
e
= 0.85 ± 0.01. It is the most evolved system found having a sub-stellar companion with such a high eccentricity and wide separation. HD 187878 B has a minimum mass of 78.4 ± 2.0
M
Jupiter
. Combining the spectroscopic orbital parameters with the astrometric proper motion anomaly, we derived an orbital inclination
i
= 9.8
−0.6
+0.4
deg, which corresponds to the companion’s mass in the stellar regime of 0.51
−0.02
+0.04
M
⊙
.
Conclusions.
A sub-stellar companion of KIC 3526061 extends the sample of known red giant branch stars with sub-stellar companions on very eccentric wide orbits, and might provide a probe of the dynamical evolution of such systems over time.
Abstract
Transit timing variations (TTVs) of Kepler-410Ab were already reported in a few papers. Their semi-amplitude is about 14.5 min. In our previous paper, we found that the TTVs could be caused ...by the presence of a stellar companion in this system. Our main motivation for this paper was to investigate variation in a radial-velocity (RV) curve generated by this additional star in the system. We performed spectroscopic observation of Kepler-410 using three telescopes in Slovakia and Czech Republic. Using the cross-correlation function, we measured the radial velocities of the star Kepler-410A. We did not observe any periodic variation in an RV curve. Therefore, we rejected our previous hypothesis about additional stellar companion in the Kepler-410 system. We ran different numerical simulations to study mean-motion resonances with Kepler-410Ab. Observed TTVs could be also explained by the presence of a small planet near to mean-motion resonance 2:3 with Kepler-410Ab. This resonance is stable on a long time-scale. We also looked for stable regions in the Kepler-410 system where another planet could exist for a long time.
We present an investigation of the transmission spectrum of the 6.5 M {circled plus} planet GJ 1214b based on new ground-based observations of transits of the planet in the optical and near-infrared, ...and on previously published data. Observations with the VLT + FORS and Magellan + MMIRS using the technique of multi-object spectroscopy with wide slits yielded new measurements of the planet's transmission spectrum from 0.61 to 0.85 Delta *mm, and in the J, H, and K atmospheric windows. We also present a new measurement based on narrow-band photometry centered at 2.09 Delta *mm with the VLT + HAWKI. We combined these data with results from a reanalysis of previously published FORS data from 0.78 to 1.00 Delta *mm using an improved data reduction algorithm, and previously reported values based on Spitzer data at 3.6 and 4.5 Delta *mm. All of the data are consistent with a featureless transmission spectrum for the planet. Our K-band data are inconsistent with the detection of spectral features at these wavelengths reported by Croll and collaborators at the level of 4.1 Delta *s. The planet's atmosphere must either have at least 70% H2O by mass or optically thick high-altitude clouds or haze to be consistent with the data.
ABSTRACT
Some theories of planet formation and evolution predict that intermediate-mass stars host more hot Jupiters than Sun-like stars, others reach the conclusion that such objects are very rare. ...By determining the frequencies of those planets we can test those theories.
Based on the analysis of Kepler light curves it has been suggested that about 8 per cent of the intermediate-mass stars could have a close-in substellar companion. This would indicate a very high frequency of such objects. Up to now, there was no satisfactory proof or test of this hypothesis.
We studied a previously reported sample of 166 planet candidates around main-sequence A-type stars in the Kepler field. We selected six of them for which we obtained extensive long-term radial velocity measurements with the Alfred Jensch 2-m telescope in Tautenburg and the Perek 2-m telescope in Ondřejov. We derive upper limits of the masses of the planet candidates. We show that we are able to detect this kind of planet with our telescopes and their instrumentation using the example of MASCARA-1 b.
With the transit finding pipeline Extrans we confirm that there is no single transit event from a Jupiter-like planet in the light curves of those 166 stars. We furthermore determine that the upper limit for the occurrence rate of close-in, massive planets for A-type stars in the Kepler sample is around 0.75 per cent.
We argue that there is currently little evidence for a very high frequency of close-in, massive planets of intermediate-mass stars.
Abstract
We performed a unique Venus observation campaign to measure the disk brightness of Venus over a broad range of wavelengths in 2020 August and September. The primary goal of the campaign was ...to investigate the absorption properties of the unknown absorber in the clouds. The secondary goal was to extract a disk mean SO
2
gas abundance, whose absorption spectral feature is entangled with that of the unknown absorber at ultraviolet wavelengths. A total of three spacecraft and six ground-based telescopes participated in this campaign, covering the 52–1700 nm wavelength range. After careful evaluation of the observational data, we focused on the data sets acquired by four facilities. We accomplished our primary goal by analyzing the reflectivity spectrum of the Venus disk over the 283–800 nm wavelengths. Considerable absorption is present in the 350–450 nm range, for which we retrieved the corresponding optical depth of the unknown absorber. The result shows the consistent wavelength dependence of the relative optical depth with that at low latitudes, during the Venus flyby by MESSENGER in 2007, which was expected because the overall disk reflectivity is dominated by low latitudes. Last, we summarize the experience that we obtained during this first campaign, which should enable us to accomplish our second goal in future campaigns.
The present study confirms BD-14\,3065b as a transiting planet-brown dwarf in a triple-star system, with a mass near the deuterium-burning boundary. BD-14\,3065b has the largest radius observed ...within the sample of giant planets and brown dwarfs around post-main sequence stars. Its orbital period is 4.3 days and it transits a subgiant F-type star with a mass of $M_ odot $, a radius of $R_ odot $, an effective temperature of $T_ eff and a metallicity of $-0.34 By combining TESS photometry with high-resolution spectra acquired with the TRES and Pucheros+ spectrographs, we measured a mass of $M_p=12.37 and a radius of $R_p=1.926 Our discussion of potential processes that could be responsible for the inflated radius led us to conclude that deuterium burning is a plausible explanation for the heating taking place in BD-14\,3065b's interior. Detections of the secondary eclipse with TESS photometry enabled a precise determination of the eccentricity, $e_p=0.066 and reveal that BD-14\,3065b has a brightness temperature of $3520 130$\,K. With its unique characteristics, BD-14\,3065b presents an excellent opportunity to study its atmosphere via thermal emission spectroscopy.
Constraints on TESS albedos for five hot Jupiters Blažek, Martin; Kabáth, Petr; Piette, Anjali A A ...
Monthly notices of the Royal Astronomical Society,
07/2022, Volume:
513, Issue:
3
Journal Article
Peer reviewed
Open access
ABSTRACT
Photometric observations of occultations of transiting exoplanets can place important constraints on the thermal emission and albedos of their atmospheres. We analyse photometric ...measurements and derive geometric albedo (Ag) constraints for five hot Jupiters observed with TESS in the optical: WASP-18 b, WASP-36 b, WASP-43 b, WASP-50 b, and WASP-51 b. For WASP-43 b, our results are complemented by a VLT/HAWK-I observation in the near-infrared at $2.09\, \mu$m. We derive the first geometric albedo constraints for WASP-50 b and WASP-51 b: Ag < 0.445 and Ag < 0.368, respectively. We find that WASP-43 b and WASP-18 b are both consistent with low geometric albedos (Ag < 0.16) even though they lie at opposite ends of the hot Jupiter temperature range with equilibrium temperatures of ∼1400 K and ∼2500 K, respectively. We report self-consistent atmospheric models that explain broad-band observations for both planets from TESS, HST, Spitzer, and VLT/HAWK-I. We find that the data of both hot Jupiters can be explained by thermal emission alone and inefficient day–night energy redistribution. The data do not require optical scattering from clouds/hazes, consistent with the low geometric albedos observed.
Meteor plasmas and impact events are complex, dynamic natural phenomena. Simulating these processes in the laboratory is, however, a challenge. The technique of laser induced dielectric breakdown was ...first used for this purpose almost 50 years ago. Since then, laser-based experiments have helped to simulate high energy processes in the Tunguska and Chicxulub impact events, heavy bombardment on the early Earth, prebiotic chemical evolution, space weathering of celestial bodies and meteor plasma. This review summarizes the current level of knowledge and outlines possible paths of future development.
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