High-energy irradiation and mass loss rates of hot Jupiters in the solar neighborhood

Salz, M.; Schneider, P. C.; Czesla, S.; Schmitt, J. H. M. M.

doi:10.1051/0004-6361/201425243

Cited by 59 publications

(71 citation statements)

References 98 publications

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“…We find that optically variable modulation exists in both survey data which is probably due to photospheric spots which persisted at fixed longitudes of HAT-P-20 for a long time, which is consistent with strong chromospheric Ca II H & K emission and X-ray emission (Bakos et al 2011;Granata et al 2014;Salz et al 2015), and both peak powers overlay quite well in the GLS periodogram (e.g., =  P 14.66 0.03 day; rot see Figure 7). …”

Section: The Magnetic Activity Of Hat-p-20supporting

confidence: 75%

“…It is a massive hot Jupiter with a mass of  M 7.246 0.03 Jup and a radius of  R 0.867 0.033 Jup . Its host star is a K3 main-sequence star, and it has a relatively strong magnetic activity (Bakos et al 2011;Shkolnik 2013;Granata et al 2014;Salz et al 2015). HAT-P-20 has a red companion (2MASS07273963+2420171, -= J K 0.92) with a   6.…”

Section: Introductionmentioning

confidence: 99%

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Refined System Parameters and TTV Study of Transiting Exoplanetary System Hat-P-20

Sun

Wang

et al. 2016

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We report new photometric observations of the transiting exoplanetary system HAT-P-20, obtained using CCD cameras at Yunnan Observatories and Ho Koon Nature Education cum Astronomical Centre, China, from 2010 to 2013, and Observatori Ca l'Ou, Sant Marti Sesgueioles, Spain, from 2013 to 2015. The observed data are corrected for systematic errors according to the coarse de-correlation and SYSREM algorithms, so as to enhance the signal of the transit events. In order to consistently model the star spots and transits of this exoplanetary system, we develop a highly efficient tool STMT based on the analytic models of Mandel & Agol and Montalto et al. The physical parameters of HAT-P-20 are refined by homogeneously analyzing our new data, the radial velocity data, and the earlier photometric data in the literature with the Markov chain Monte Carlo technique. New radii and masses of both host star and planet are larger than those in the discovery paper due to the discrepancy of the radius among K-dwarfs between predicted values by standard stellar models and empirical calibration from observations. Through the analysis of all available mid-transit times calculated with the normal model and spotted model, we conclude that the periodic transit timing variations in these transit events revealed by employing the normal model are probably induced by spot crossing events. From the analysis of the distribution of occulted spots by HAT-P20b, we constrain the misaligned architecture between the planetary orbit and the spin of the host star.

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Section: The Magnetic Activity Of Hat-p-20supporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Refined System Parameters and TTV Study of Transiting Exoplanetary System Hat-P-20

Sun

Wang

et al. 2016

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“…The data were compiled using exoplanets.org (Wright et al 2011) and the following publications: HAT-P-2: Bakos et al (2007), van Leeuwen (2007), Pál et al (2010), P rot from v sin i, T eq varies due to eccentricity ( (Salz et al 2015b); HAT-P-20: Bakos et al (2011), P rot from (Salz et al 2015b); WASP-8: Queloz et al (2010), Cubillos et al (2012), P rot from (Salz et al 2015b); WASP-80: Triaud et al (2013), P rot from v sin i; WASP-43: Hellier et al (2011);WASP-18: Hellier et al (2009), Pillitteri et al (2014, P rot from v sin i; HD 209458: Charbonneau et al (2000), Henry et al (2000), Torres et al (2008), Silva-Valio (2008), dayside brightness temperature from Spitzer observation (Crossfield et al 2012);HD 189733: Bouchy et al (2005), Henry & Winn (2008), Southworth (2010), dayside brightness temperature from Spitzer observation (Knutson et al 2007);GJ 1214), Berta et al (2011), Narita et al (2013; GJ 3470: Bonfils et al (2012), Biddle et al (2014);GJ 436: Butler et al (2004), Knutson et al (2011);55 Cnc: Butler et al (1997), McArthur et al (2004, Gray et al (2003), Fischer et al (2008); HAT-P-11: Bakos et al (2010);HD 149026: Sato et al (2005), P rot from v sin i, dayside brightness temperature from Spitzer observation (Knutson et al 2009);HD 97658: Howard et al (2011…”

Section: Target Selectionmentioning

confidence: 99%

Simulating the escaping atmospheres of hot gas planets in the solar neighborhood

Salz

Czesla

Schneider

et al. 2016

A&A

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172

326

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Absorption of high-energy radiation in planetary thermospheres is generally believed to lead to the formation of planetary winds. The resulting mass-loss rates can affect the evolution, particularly of small gas planets. We present 1D, spherically symmetric hydrodynamic simulations of the escaping atmospheres of 18 hot gas planets in the solar neighborhood. Our sample only includes strongly irradiated planets, whose expanded atmospheres may be detectable via transit spectroscopy using current instrumentation. The simulations were performed with the PLUTO-CLOUDY interface, which couples a detailed photoionization and plasma simulation code with a general MHD code. We study the thermospheric escape and derive improved estimates for the planetary mass-loss rates. Our simulations reproduce the temperature-pressure profile measured via sodium D absorption in HD 189733 b, but show still unexplained differences in the case of HD 209458 b. In contrast to general assumptions, we find that the gravitationally more tightly bound thermospheres of massive and compact planets, such as HAT-P-2 b are hydrodynamically stable. Compact planets dispose of the radiative energy input through hydrogen Lyα and free-free emission. Radiative cooling is also important in HD 189733 b, but it decreases toward smaller planets like GJ 436 b. Computing the planetary Lyα absorption and emission signals from the simulations, we find that the strong and cool winds of smaller planets mainly cause strong Lyα absorption but little emission. Compact and massive planets with hot, stable thermospheres cause small absorption signals but are strong Lyα emitters, possibly detectable with the current instrumentation. The absorption and emission signals provide a possible distinction between these two classes of thermospheres in hot gas planets. According to our results, WASP-80 and GJ 3470 are currently the most promising targets for observational follow-up aimed at detecting atmospheric Lyα absorption signals.

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“…Since the resulting temperaturepressure profile (see below Fig. 12) is consistent with the rise of temperature with the altitude observed by Huitson et al (2012), we adopt the Salz et al (2015)'s profiles to describe for r ≥ R p the thermosphere of HD 189733b. Line et al (2014) showed from secondary eclipse spectroscopy that for R p ≥ r ≥ r in , corresponding to an atmospheric pressure increasing from p(R p ) ∼10 to p(r in ) ∼ 1000 dyn cm −2 , the lower atmosphere of HD 189733b is isothermal, with an equilibrium temperature of T eq ∼ 1200 K. Therefore, we use the hydrostatic equilibrium to extent the pressure and density profiles into this lower atmospheric layer.…”

Section: Model Of the Hd 189733b Atmospherementioning

confidence: 71%

“…Huitson et al (2012) detected an upper atmospheric heating of HD 189733b from HST sodium observations, i.e., evidence of a thermosphere. Salz et al (2015) obtained a 1D, spherically symmetric hydrodynamic simulations of the escaping atmosphere of HD 189733b, predicting gas velocity of ∼9 km s −1 at the Roche's radius, R Roche = 4.35 R p (Fig. 7), by coupling a detailed photoionization and plasma simulation code with a general MHD code, and assuming only atomic Hydrogen an Helium in the atmosphere.…”

Section: Model Of the Hd 189733b Atmospherementioning

confidence: 99%

Computation of the Transmitted and Polarized Scattered Fluxes by the Exoplanet HD 189733b in X-Rays

Marin

Grosso

2017

ApJ

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Thousands of exoplanets have been detected, but only one exoplanetary transit was potentially observed in X-rays from HD 189733A. What makes the detection of exoplanets so difficult in this band? To answer this question, we run Monte-Carlo radiative transfer simulations to estimate the amount of X-ray flux reprocessed by HD 189733b Despite its extended evaporating-atmosphere, we find that the X-ray absorption radius of HD 189733b at 0.7 keV, the mean energy of the photons detected in the 0.25-2 keV energy band by XMM-Newton, is ∼1.01 times the planetary radius for an atmosphere of atomic Hydrogen and Helium (including ions), and produces a maximum depth of ∼2.1% at ∼±46 min from the center of the planetary transit on the geometrically thick and optically thin corona. We compute numerically in the 0.25-2 keV energy band that this maximum depth is only of ∼1.6% at ∼±47 min from the transit center, and little sensitive to the metal abundance assuming that adding metals in the atmosphere would not dramatically change the density-temperature profile. Regarding a direct detection of HD 189733b in X-rays, we find that the amount of flux reprocessed by the exoplanetary atmosphere varies with the orbital phase, spanning between 3-5 orders of magnitude fainter than the flux of the primary star. Additionally, the degree of linear polarization emerging from HD 189733b is <0.003%, with maximums detected near planetary greatest elongations. This implies that both the modulation of the X-ray flux with the orbital phase and the scattered-induced continuum polarization cannot be observed with current X-ray facilities.

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High-energy irradiation and mass loss rates of hot Jupiters in the solar neighborhood

Cited by 59 publications

References 98 publications

Refined System Parameters and TTV Study of Transiting Exoplanetary System Hat-P-20

Refined System Parameters and TTV Study of Transiting Exoplanetary System Hat-P-20

Simulating the escaping atmospheres of hot gas planets in the solar neighborhood

Computation of the Transmitted and Polarized Scattered Fluxes by the Exoplanet HD 189733b in X-Rays

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