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.

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 WASP-180Ab: Doppler tomography of a hot Jupiter orbiting the primary star in a visual binary

2019 ◽  
Vol 490 (2) ◽  
pp. 2467-2474
Author(s):  
L Y Temple ◽  
C Hellier ◽  
D R Anderson ◽  
K Barkaoui ◽  
F Bouchy ◽  
...  
Keyword(s):  
Binary Systems ◽  
Rotation Speed ◽  
Small Sample ◽  
Primary Star ◽  
Doppler Tomography ◽  
Companion Star ◽  
Hot Jupiters ◽  
Rotational Modulation ◽  
Hot Jupiter

ABSTRACT We report the discovery and characterization of WASP-180Ab, a hot Jupiter confirmed by the detection of its Doppler shadow and by measuring its mass using radial velocities. We find the 0.9  ±  0.1 MJup, 1.24  ±  0.04 RJup planet to be in a misaligned, retrograde orbit around an F7 star with Teff  =  6500 K and a moderate rotation speed of vsin i⋆  =  19.9 km s−1. The host star is the primary of a V  =  10.7 binary, where a secondary separated by ∼5 arcsec (∼1200 au) contributes ∼ 30 per cent of the light. WASP-180Ab therefore adds to a small sample of transiting hot Jupiters known in binary systems. A 4.6-d modulation seen in the WASP data is likely to be the rotational modulation of the companion star, WASP-180B.

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.

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.

scholarly journals A data-driven approach to constraining the atmospheric temperature structure of the ultra-hot Jupiter KELT-9b

2020 ◽  
Vol 643 ◽  
pp. A131
Author(s):  
L. Fossati ◽  
D. Shulyak ◽  
A. G. Sreejith ◽  
T. Koskinen ◽  
M. E. Young ◽  
...  
Keyword(s):  
Mass Loss ◽  
Thermodynamic Equilibrium ◽  
Local Thermodynamic Equilibrium ◽  
Mass Loss Rate ◽  
Atmospheric Temperature ◽  
High Mass ◽  
Temperature Structure ◽  
Hot Jupiters ◽  
Data Driven Approach ◽  
Hot Jupiter

Context. Observationally constraining the atmospheric temperature-pressure (TP) profile of exoplanets is an important step forward for improving planetary atmosphere models, thus further enabling one to place the detection of spectral features and the measurement of atomic and molecular abundances through transmission and emission spectroscopy on solid ground. Aims. The aim is to constrain the TP profile of the ultra-hot Jupiter KELT-9b by fitting synthetic spectra to the observed Hα and Hβ lines and identify why self-consistent planetary TP models are unable to fit the observations. Methods. We constructed 126 one-dimensional TP profiles varying the lower and upper atmospheric temperatures, as well as the location and gradient of the temperature rise. For each TP profile, we computed the transmission spectra of the Hα and Hβ lines employing the Cloudy radiative transfer code, which self-consistently accounts for non-local thermodynamic equilibrium (NLTE) effects. Results. The TP profiles, leading to best fit the observations, are characterised by an upper atmospheric temperature of 10 000–11 000 K and by an inverted temperature profile at pressures higher than 10−4 bar. We find that the assumption of local thermodynamic equilibrium (LTE) leads one to overestimate the level population of excited hydrogen by several orders of magnitude and hence to significantly overestimate the strength of the Balmer lines. The chemical composition of the best fitting models indicate that the high upper atmospheric temperature is most likely driven by metal photoionisation and that FeII and FeIII have comparable abundances at pressures lower than 10−6 bar, possibly making the latter detectable. Conclusions. Modelling the atmospheres of ultra-hot Jupiters requires one to account for metal photoionisation. The high atmospheric mass-loss rate (>1011 g s−1), caused by the high temperature, may have consequences on the planetary atmospheric evolution. Other ultra-hot Jupiters orbiting early-type stars may be characterised by similarly high upper atmospheric temperatures and hence high mass-loss rates. This may have consequences on the basic properties of the observed planets orbiting hot stars.

scholarly journals Constraining the orbit of the planet-hosting binary τ Boötis

2019 ◽  
Vol 625 ◽  
pp. A59 ◽  
Author(s):  
A. B. Justesen ◽  
S. Albrecht
Keyword(s):  
High Eccentricity ◽  
Primary Star ◽  
Orbital Inclination ◽  
Hot Jupiters ◽  
Migration History ◽  
History Of ◽  
And Migration ◽  
Planetary Migration ◽  
Astrometric Data ◽  
Hot Jupiter

Context. The formation of planets in compact or highly eccentric binaries and the migration of hot Jupiters are two outstanding problems in planet formation. Detailed characterisation of known systems is important for informing and testing models. The hot Jupiter τ Boo Ab orbits the primary star in the long-period (P ≳ 1000 yr), highly eccentric (e ~ 0.9) double star system τ Boötis. Due to the long orbital period, the orbit of the stellar binary is poorly constrained. Aims. Here we aim to constrain the orbit of the stellar binary τ Boo AB in order to investigate the formation and migration history of the system. The mutual orbital inclination of the stellar companion and the hot Jupiter has important implications for planet migration. The binary eccentricity and periastron distance are important for understanding the conditions under which τ Boo Ab formed. Methods. We combine more than 150 yr of astrometric data with twenty-five years of high-precision radial velocities. The combination of sky-projected and line-of-sight measurements places tight constraints on the orbital inclination, eccentricity, and periastron distance of τ Boo AB. Results. We determine the orbit of τ Boo B and find an orbital inclination of 47.2−3.7+2.7°, a periastron distance of 28.3−3.0+2.3 au, and an eccentricity of 0.87−0.03+0.04. We find that the orbital inclinations of τ Boo Ab and τ Boo B, as well as the stellar spin-axis of τ Boo A coincide at ~45°, a result consistent with the assumption of a well-aligned, coplanar system. Conclusions. The likely aligned, coplanar configuration suggests planetary migration within a well-aligned protoplanetary disc. Due to the high eccentricity and small periastron distance of τ Boo B, the protoplanetary disc was tidally truncated at ≈6 au. We suggest that τ Boo Ab formed near the edge of the truncated disc and migrated inwards with high eccentricity due to spiral waves generated by the stellar companion.

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

&lt;p&gt;Thanks to the different Doppler velocities of the Earth, the&amp;#160;host star and the planet using high-resolution spectroscopy we&amp;#160;are able to detect and characterise exoplanetary atmospheres.&amp;#160;Exoplanetary signal is buried in the residual noise, however&amp;#160;by preforming cross-correlation of atmospheric transmission&amp;#160;model and hundreds of atmospheric lines the signal can be&amp;#160;increase. Studying the atmospheres of ultra-hot Jupiters,&amp;#160;objects with the temperature higher than 2200K which orbit&amp;#160;close to their host stars, gives us great laboratory to study&amp;#160;chemistry of the exoplanets. MASCARA-2b also known as KELT-20b&amp;#160;with the temperature of 2230 K is a perfect example of ultra&amp;#160;hot Jupiter. We studied this object using three transit&amp;#160;observations obtained with HARPS-North. Using cross-correlation&amp;#160;method we detected strong absorption of Fe I and&amp;#160;FeII, which agrees with theoretical models. Additionally,&amp;#160;because of the fast rotation of the star, the crosscorrelation&amp;#160;residuals show strong Rossiter-MacLaughlin effect.&lt;/p&gt;

scholarly journals How Complete Are Surveys for Nearby Transiting Hot Jupiters?

2021 ◽  
Vol 162 (6) ◽  
pp. 240
Author(s):  
Samuel W. Yee ◽  
Joshua N. Winn ◽  
Joel D. Hartman
Keyword(s):  
Planet Formation ◽  
Galactic Plane ◽  
Selection Function ◽  
Limited Sample ◽  
Hot Jupiters ◽  
Kepler Mission ◽  
Order Of Magnitude ◽  
Host Stars ◽  
Hot Jupiter

Abstract Hot Jupiters are a rare and interesting outcome of planet formation. Although more than 500 hot Jupiters (HJs) are known, most of them were discovered by a heterogeneous collection of surveys with selection biases that are difficult to quantify. Currently, our best knowledge of HJ demographics around FGK stars comes from the sample of ≈40 objects detected by the Kepler mission, which have a well-quantified selection function. Using the Kepler results, we simulate the characteristics of the population of nearby transiting HJs. A comparison between the known sample of nearby HJs and simulated magnitude-limited samples leads to four conclusions. (1) The known sample of HJs appears to be ≈75% complete for stars brighter than Gaia G ≤ 10.5, falling to ≲50% for G ≤ 12. (2) There are probably a few undiscovered HJs with host stars brighter than G ≈ 10 located within 10° of the Galactic plane. (3) The period and radius distributions of HJs may differ for F-type hosts (which dominate the nearby sample) and G-type hosts (which dominate the Kepler sample). (4) To obtain a magnitude-limited sample of HJs that is larger than the Kepler sample by an order of magnitude, the limiting magnitude should be approximately G ≈ 12.5. This magnitude limit is within the range for which NASA’s Transiting Exoplanet Survey Satellite can easily detect HJs, presenting the opportunity to greatly expand our knowledge of hot-Jupiter demographics.

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