Exoplanets: Atmospheres of Hot Jupiters

2019 ◽  
Author(s):  
Dmitry V. Bisikalo ◽  
Pavel V. Kaygorodov ◽  
Valery I. Shematovich
Keyword(s):  
Solar System ◽  
Alternative Hypothesis ◽  
Atmospheric Composition ◽  
Current Status ◽  
Hot Jupiters ◽  
History Of ◽  
Exoplanetary Atmospheres ◽  
Host Stars ◽  
Gaseous Envelopes ◽  
Hot Jupiter

The history of exoplanetary atmospheres studies is strongly based on the observations and investigations of the gaseous envelopes of hot Jupiters—exoplanet gas giants that have masses comparable to the mass of Jupiter and orbital semi-major axes shorter than 0.1 AU. The first exoplanet around a solar-type star was a hot Jupiter discovered in 1995. Researchers found an object that had completely atypical parameters compared to planets known in the solar system. According to their estimates, the object might have a mass about a half of the Jovian mass and a very short orbital period (four days), which means that it has an orbit roughly corresponding to the orbit of Mercury. Later, many similar objects were discovered near different stars, and they acquired a common name—hot Jupiters. It is still unclear what the mechanism is for their origin, because generally accepted theories of planetary evolution predict the formation of giant planets only at large orbital distances, where they can accrete enough matter before the protoplanetary disc disappears. If this is true, before arriving at such low orbits, hot Jupiters might have a long migration path, caused by interactions with other massive planets and/or with the gaseous disc. In favor of this model is the discovery of many hot Jupiters in elliptical and highly inclined orbits, but on the other hand several observed hot Jupiters have circular orbits with low inclination. An alternative hypothesis is that the cores of future hot Jupiters are super-Earths that may later intercept matter from the protoplanetary disk falling on the star. The scientific interest in hot Jupiters has two aspects. The first is the peculiarity of these objects: they have no analogues in the solar system. The second is that, until recently, only for hot Jupiters was it possible to obtain observational characteristics of their atmospheres. Many of the known hot Jupiters are eclipsing their host stars, so, from their light curve and spectral data obtained during an eclipse, it became possible to obtain information about their shape and their atmospheric composition. Thus it is possible to conclude that hot Jupiters are a common type of exoplanet, having no analogues in the solar system. Many aspects of their evolution and internal structure remain unclear. Being very close to their host stars, hot Jupiters must interact with the stellar wind and stellar magnetic field, as well as with stellar flares and coronal mass ejections, allowing researchers to gather information about them. According to UV observations, at least a fraction of hot Jupiters have extended gaseous envelopes, extending far beyond of their upper atmospheres. The envelopes are observable with current astronomical instruments, so it is possible to develop their astrophysical models. The history of hot Jupiter atmosphere studies during the past 20 years and the current status of modern theories describing the extended envelopes of hot Jupiters are excellent examples of the progress in understanding planetary atmospheres formation and evolution both in the solar system and in the extrasolar planetary systems.

scholarly journals An optical transmission spectrum of the ultra-hot Jupiter WASP-33 b

2019 ◽  
Vol 622 ◽  
pp. A71 ◽  
Author(s):  
C. von Essen ◽  
M. Mallonn ◽  
L. Welbanks ◽  
N. Madhusudhan ◽  
A. Pinhas ◽  
...  
Keyword(s):  
Light Curves ◽  
Atmospheric Composition ◽  
Data Sets ◽  
Hot Jupiters ◽  
High Data ◽  
Trace Species ◽  
Exoplanetary Atmospheres ◽  
Combined Data ◽  
Hot Jupiter

There has been increasing progress toward detailed characterization of exoplanetary atmospheres, in both observations and theoretical methods. Improvements in observational facilities and data reduction and analysis techniques are enabling increasingly higher quality spectra, especially from ground-based facilities. The high data quality also necessitates concomitant improvements in models required to interpret such data. In particular, the detection of trace species such as metal oxides has been challenging. Extremely irradiated exoplanets (~3000 K) are expected to show oxides with strong absorption signals in the optical. However, there are only a few hot Jupiters where such signatures have been reported. Here we aim to characterize the atmosphere of the ultra-hot Jupiter WASP-33 b using two primary transits taken 18 orbits apart. Our atmospheric retrieval, performed on the combined data sets, provides initial constraints on the atmospheric composition of WASP-33 b. We report a possible indication of aluminum oxide (AlO) at 3.3-σ significance. The data were obtained with the long slit OSIRIS spectrograph mounted at the 10-m Gran Telescopio Canarias. We cleaned the brightness variations from the light curves produced by stellar pulsations, and we determined the wavelength-dependent variability of the planetary radius caused by the atmospheric absorption of stellar light. A simultaneous fit to the two transit light curves allowed us to refine the transit parameters, and the common wavelength coverage between the two transits served to contrast our results. Future observations with HST as well as other large ground-based facilities will be able to further constrain the atmospheric chemical composition of the planet.

scholarly journals High-resolution Imaging of Transiting Extrasolar Planetary systems (HITEP)

2018 ◽  
Vol 610 ◽  
pp. A20 ◽  
Author(s):  
D. F. Evans ◽  
J. Southworth ◽  
B. Smalley ◽  
U. G. Jørgensen ◽  
M. Dominik ◽  
...  
Keyword(s):  
Target Selection ◽  
High Mass ◽  
Line Of Sight ◽  
Companion Star ◽  
Formation Pathway ◽  
Hot Jupiters ◽  
Potential Formation ◽  
History Of ◽  
Host Stars ◽  
Hot Jupiter

Context. The formation and dynamical history of hot Jupiters is currently debated, with wide stellar binaries having been suggested as a potential formation pathway. Additionally, contaminating light from both binary companions and unassociated stars can significantly bias the results of planet characterisation studies, but can be corrected for if the properties of the contaminating star are known. Aim. We search for binary companions to known transiting exoplanet host stars, in order to determine the multiplicity properties of hot Jupiter host stars. We also search for and characterise unassociated stars along the line of sight, allowing photometric and spectroscopic observations of the planetary system to be corrected for contaminating light. Methods. We analyse lucky imaging observations of 97 Southern hemisphere exoplanet host stars, using the Two Colour Instrument on the Danish 1.54 m telescope. For each detected companion star, we determine flux ratios relative to the planet host star in two passbands, and measure the relative position of the companion. The probability of each companion being physically associated was determined using our two-colour photometry. Results. A catalogue of close companion stars is presented, including flux ratios, position measurements, and estimated companion star temperature. For companions that are potential binary companions, we review archival and catalogue data for further evidence. For WASP-77AB and WASP-85AB, we combine our data with historical measurements to determine the binary orbits, showing them to be moderately eccentric and inclined to the line of sight (and hence planetary orbital axis). Combining our survey with the similar Friends of Hot Jupiters survey, we conclude that known hot Jupiter host stars show a deficit of high mass stellar companions compared to the field star population; however, this may be a result of the biases in detection and target selection by ground-based surveys.

Fe I and Fe II in the atmosphere of Ultra-hot Jupiter MASCARA-2b

2020 ◽  
Author(s):  
Monika Stangret ◽  
Núria Casasayas-Barris ◽  
Enric Palle ◽  
Fei Yan ◽  
Alejandro Sánchez-López ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Theoretical Models ◽  
High Resolution Spectroscopy ◽  
Atmospheric Transmission ◽  
Hot Jupiters ◽  
Residual Noise ◽  
The Earth ◽  
Exoplanetary Atmospheres ◽  
Host Stars ◽  
Hot Jupiter

<p>Thanks to the different Doppler velocities of the Earth, the host star and the planet using high-resolution spectroscopy we are able to detect and characterise exoplanetary atmospheres. Exoplanetary signal is buried in the residual noise, however by preforming cross-correlation of atmospheric transmission model and hundreds of atmospheric lines the signal can be increase. Studying the atmospheres of ultra-hot Jupiters, objects with the temperature higher than 2200K which orbit close to their host stars, gives us great laboratory to study chemistry of the exoplanets. MASCARA-2b also known as KELT-20b with the temperature of 2230 K is a perfect example of ultra hot Jupiter. We studied this object using three transit observations obtained with HARPS-North. Using cross-correlation method we detected strong absorption of Fe I and FeII, which agrees with theoretical models. Additionally, because of the fast rotation of the star, the crosscorrelation residuals show strong Rossiter-MacLaughlin effect.</p>

scholarly journals In Situ exploration of the giant planets

2021 ◽  
Author(s):  
O. Mousis ◽  
D. H. Atkinson ◽  
R. Ambrosi ◽  
S. Atreya ◽  
D. Banfield ◽  
...  
Keyword(s):  
Solar System ◽  
Giant Planets ◽  
Atmospheric Composition ◽  
Formation History ◽  
History Of ◽  
Composition Structure ◽  
Galileo Probe ◽  
Probe Measurements

AbstractRemote sensing observations suffer significant limitations when used to study the bulk atmospheric composition of the giant planets of our Solar System. This impacts our knowledge of the formation of these planets and the physics of their atmospheres. A remarkable example of the superiority of in situ probe measurements was illustrated by the exploration of Jupiter, where key measurements such as the determination of the noble gases’ abundances and the precise measurement of the helium mixing ratio were only made available through in situ measurements by the Galileo probe. Here we describe the main scientific goals to be addressed by the future in situ exploration of Saturn, Uranus, and Neptune, placing the Galileo probe exploration of Jupiter in a broader context. An atmospheric entry probe targeting the 10-bar level would yield insight into two broad themes: i) the formation history of the giant planets and that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. An atmospheric probe could represent a significant ESA contribution to a future NASA New Frontiers or flagship mission to be launched toward Saturn, Uranus, and/or Neptune.

scholarly journals Connecting planet formation and astrochemistry

2019 ◽  
Vol 632 ◽  
pp. A63 ◽  
Author(s):  
Alex J. Cridland ◽  
Ewine F. van Dishoeck ◽  
Matthew Alessi ◽  
Ralph E. Pudritz
Keyword(s):  
Solar System ◽  
Planet Formation ◽  
Water Ice ◽  
Hot Jupiters ◽  
Formation History ◽  
General Mass ◽  
Exoplanetary Atmospheres ◽  
Molecular Abundances ◽  
Gas Accretion ◽  
Oxygen Ratio

To understand the role that planet formation history has on the observable atmospheric carbon-to-oxygen ratio (C/O) we have produced a population of astrochemically evolving protoplanetary disks. Based on the parameters used in a pre-computed population of growing planets, their combination allows us to trace the molecular abundances of the gas that is being collected into planetary atmospheres. We include atmospheric pollution of incoming (icy) planetesimals as well as the effect of refractory carbon erosion noted to exist in our own solar system. We find that the carbon and oxygen content of Neptune-mass planets are determined primarily through solid accretion and result in more oxygen-rich (by roughly two orders of magnitude) atmospheres than hot Jupiters, whose C/O are primarily determined by gas accretion. Generally we find a “main sequence” between the fraction of planetary mass accreted through solid accretion and the resulting atmospheric C/O; planets of higher solid accretion fraction have lower C/O. Hot Jupiters whose atmospheres have been chemically characterized agree well with our population of planets, and our results suggest that hot-Jupiter formation typically begins near the water ice line. Lower mass hot Neptunes are observed to be much more carbon rich (with 0.33 ≲ C/O ≲ 1) than is found in our models (C/O ~ 10−2), and suggest that some form of chemical processing may affect their observed C/O over the few billion years between formation and observation. Our population reproduces the general mass-metallicity trend of the solar system and qualitatively reproduces the C/O metallicity anti-correlation that has been inferred for the population of characterized exoplanetary atmospheres.

scholarly journals Planets spinning up their host stars: a twist on the age-activity relationship

2013 ◽  
Vol 9 (S302) ◽  
pp. 239-242
Author(s):  
K. Poppenhaeger ◽  
S. J. Wolk
Keyword(s):  
Magnetic Activity ◽  
Negative Control ◽  
Detection Methods ◽  
Close Binaries ◽  
Activity Levels ◽  
Planet Detection ◽  
Hot Jupiters ◽  
Cool Stars ◽  
Host Stars ◽  
Hot Jupiter

AbstractIt is a long-standing question in exoplanet research if Hot Jupiters can influence the magnetic activity of their host stars. While cool stars usually spin down with age and become inactive, an input of angular momentum through tidal interaction, as seen for example in close binaries, can preserve high activity levels over time. This may also be the case for cool stars hosting a Hot Jupiter. However, selection effects from planet detection methods often dominate the activity levels seen in samples of exoplanet host stars, and planet-induced, systematically enhanced stellar activity has not been detected unambiguously so far. We have developed an approach to identify planet-induced stellar spin-up avoiding the selection biases from planet detection, by using visual proper motion binaries in which only one of the stars possesses a Hot Jupiter. This approach immediately rids one of the ambiguities of detection biases: with two co-eval stars, the second star acts as a negative control. We present results from our ongoing observational campaign at X-ray wavelengths and in the optical, and present several outstanding systems which display significant age/activity discrepancies presumably caused by their Hot Jupiters.

Studies of the atmosphere of ultra-hot Jupiter TOI-1431b/MASCARA-5b

2021 ◽  
Author(s):  
Monika Stangret ◽  
Enric Palle ◽  
Núria Casasayas-Barris ◽  
Mahmoud Oshagh
Keyword(s):  
High Resolution ◽  
Cross Correlation ◽  
Giant Planets ◽  
High Resolution Spectroscopy ◽  
Polar Orbit ◽  
Hot Jupiters ◽  
History Of ◽  
F Stars ◽  
Suitable Object ◽  
Hot Jupiter

<p>Ultra-hot Jupiters are defined as giant planets with equilibrium temperatures larger than 2000 K. Most of them are found orbiting bright A-F stars, making them extremely suitable object to study their atmospheres using high-resolution spectroscopy.</p> <p>TOI-1431b, also known as MASCARA-5b, a newly discovered planet with the temperature of 2375 K is a prefect example of ultra-hot Jupiter. We studied this object using three transit observations obtained with high-resolution spectrographs HARPS-N and EXPRES. Analysis of Rossiter-McLaughlin effect shows that the planet is in the polar orbit, which speaks about an interesting dynamical history, and perhaps indicating the presence of more than one planet in the early history of this system. Applying the cross-correlation and transmission spectroscopy method, we find no evidence of atoms and molecules in this planet. There results are at odds with the other studies of similar UHJs orbiting bright stars, where various species have been found.</p>

scholarly journals Optical hydrogen absorption consistent with a bow shock around the hot Jupiter HD 189733 b

2015 ◽  
Vol 11 (S320) ◽  
pp. 376-381 ◽  
Author(s):  
P. Wilson Cauley ◽  
Seth Redfield ◽  
Adam G. Jensen ◽  
Travis Barman ◽  
Michael Endl ◽  
...  
Keyword(s):  
Stellar Wind ◽  
Bow Shock ◽  
Transmission Spectra ◽  
Shock Model ◽  
Hot Jupiters ◽  
Balmer Lines ◽  
Planetary Magnetic Field ◽  
Host Stars ◽  
Hot Jupiter

AbstractHot Jupiters, i.e., Jupiter-mass planets with orbital semi major axes of <10 stellar radii, can interact strongly with their host stars. If the planet is moving supersonically through the stellar wind, a bow shock will form ahead of the planet where the planetary magnetosphere slams into the the stellar wind or where the planetary outflow and stellar wind meet. Here we present high resolution spectra of the hydrogen Balmer lines for a single transit of the hot Jupiter HD 189733 b. Transmission spectra of the Balmer lines show strong absorption ~70 minutes before the predicted optical transit, implying a significant column density of excited hydrogen orbiting ahead of the planet. We show that a simple geometric bow shock model is able to reproduce the important features of the absorption time series while simultaneously matching the line profile morphology. Our model suggests a large planetary magnetic field strength of ~28 G. Follow-up observations are needed to confirm the pre-transit signal and investigate any variability in the measurement.

One of Ten Billion Earths

2018 ◽  
Author(s):  
Karel Schrijver
Keyword(s):  
Solar System ◽  
White Dwarfs ◽  
Planetary Systems ◽  
Deep Space ◽  
Extraterrestrial Life ◽  
Distant Future ◽  
Hot Jupiters ◽  
History Of ◽  
The Universe

Illustrated with breathtaking images of the Solar System and of the Universe around it, this book explores how the discoveries within the Solar System and of distant exoplanets come together to aid understanding of the habitability of Earth, and how this guides the search for exoplanets that could support life. The author recounts how, within two decades of the discovery of the first planets outside the Solar System in the 1990s, scientists concluded that planets are so common that most stars are orbited by them. The twelve chapters highlight what we have learned about exoplanets and how the lives of exoplanets and their stars are inextricably interwoven. Stars are the seeds around which planetary systems form. Stars provide their planets with light and warmth for as long as they shine. At the end of their lives, stars expel massive amounts of newly forged elements into deep space. That ejected material is incorporated into subsequent generations of planets. How do we learn about these distant worlds? What does the exploration of other planets tell us about the history of Earth? Can we find out what the distant future may have in store for us? What do we know about exoworlds and starbirth, and where do migrating hot Jupiters, polluted white dwarfs, and free-roaming nomad planets fit in? What does all that have to do with the habitability of Earth and the possibility of finding extraterrestrial life? And how did the globe-spanning network of the sciences begin to answer all these questions?

scholarly journals A Precise Carbon and Oxygen Abundance Determination in a Hot Jupiter Atmosphere

2021 ◽  
Author(s):  
Michael Line ◽  
Matteo Brogi ◽  
Jacob Bean ◽  
Siddharth Gandhi ◽  
Joseph Zalesky ◽  
...  
Keyword(s):  
Giant Planet ◽  
High Resolution Spectroscopy ◽  
Relative Role ◽  
Quarter Century ◽  
System Architectures ◽  
Hot Jupiters ◽  
Upper Limits ◽  
Gas Accretion ◽  
Host Stars ◽  
Hot Jupiter

Abstract The origins of gas giant planets orbiting close to their host stars (``hot Jupiters'') remain a mystery despite more than a quarter-century of study (Fortney et al. 2021). The atmospheric compositions of these planets are highly sought after to provide insight to their formation location in protoplanetary disks, how they migrated to be so close to their host stars, and the relative role of solid versus gas accretion during their assembly (Madhusudhan 2019). However, simultaneous, bounded constraints on both carbon and oxygen abundances, which are key for understanding giant planet formation (Oeberg et al. 2011, Mordasini et al. 2016, Madhusudhan et al. 2017,Cridland et al. 2016), have been elusive (Kreidberg et al. 2014,Wakeford et al. 2018,Pelletier et al. 2021). Here, we report precise abundance measurements of both water and carbon monoxide in a hot Jupiter atmosphere via ground-based, high resolution spectroscopy. From these constraints on the primary carbon- and oxygen-bearing molecules, paired with upper limits on other minor volatile elemental carriers, we are able to derive the atmospheric elemental metal enrichment (metallicity) and the carbon-to-oxygen ratio (C/O). The inferred atmospheric metallicity is slightly sub-stellar (-0.48$+0.15/-0.13) and the C/O is consistent with stellar (0.59 ±0.08). The former is suggestive of a metal-depleted atmosphere relative to expectations based on extrapolation from the solar system, indicative of a greater partitioning of metals within the core vs the atmosphere. The C/O constraint rules out gas-dominated accretion followed by disk free migration. Taken together in the context of past inferences, these results point to a diversity of planetary atmospheric compositions in addition to the observed diversity of planetary system architectures.

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