GMRT search for 150 MHz radio emission from the transiting extrasolar planets HD 189733 b and HD 209458 b

Étangs, A. Lecavelier des; Sirothia, S. K.; Gopal-Krishna, . .; Zarka, Philippe

doi:10.1051/0004-6361/201117330

Cited by 45 publications

(22 citation statements)

References 47 publications

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“…Planetary magnetic fields are rarely invoked in models of giant planet formation and evolution due to the complexity of the processes involved and lack of data. In fact, the strength of any exoplanetary fields is completely unknown and only inferred by making comparisons with Jupiter, while more direct measurements using radio emission have not yet succeeded (e.g., Lecavelier Des Etangs et al 2011).…”

Section: Magnetic Star-planet Interactionsmentioning

confidence: 99%

An Ultraviolet Investigation of Activity on Exoplanet Host Stars

Shkolnik

2013

ApJ

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Using the far-UV (FUV) and near-UV (NUV) photometry from the NASA Galaxy Evolution Explorer (GALEX), we searched for evidence of increased stellar activity due to tidal and/or magnetic star-planet interactions (SPI) in the 272 known FGK planetary hosts observed by GALEX. With the increased sensitivity of GALEX, we are able probe systems with lower activity levels and at larger distances than what has been done to date with X-ray satellites. We compared samples of stars with close-in planets (a < 0.1 AU) to those with far-out planets (a > 0.5 AU) and looked for correlations of excess activity with other system parameters. This statistical investigation found no clear correlations with a, M p , or M p /a, in contrast to some X-ray and Ca ii studies. However, there is tentative evidence (at a level of 1.8σ ) that stars with radial-velocity-(RV)-detected close-in planets are more FUV-active than stars with far-out planets, in agreement with several published X-ray and Ca ii results. The case is strengthened to a level of significance to 2.3σ when transit-detected close-in planets are included. This is most likely because the RV-selected sample of stars is significantly less active than the field population of comparable stars, while the transit-selected sample is similarly active. Given the factor of 2-3 scatter in fractional FUV luminosity for a given stellar effective temperature, it is necessary to conduct a time-resolved study of the planet hosts in order to better characterize their UV variability and generate a firmer statistical result.

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Section: Magnetic Star-planet Interactionsmentioning

confidence: 99%

An Ultraviolet Investigation of Activity on Exoplanet Host Stars

Shkolnik

2013

ApJ

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“…Magnetodynamo-hosting planets around other stars could presumably emit at similar frequencies and power levels [Hess and Zarka, 2011]. Searches for Jupiterlike emission from giant exoplanets have been undertaken [Bastian et al, 2000;Lazio and Farrell, 2007;George and Stevens, 2007;Farrell et al, 2004;Lazio et al, 2010aLazio et al, , 2010bLecavelier Des Etangs et al, 2011]. However, predicted frequencies for Earth-like dynamos are below the 10 MHz cutoff of Earth's ionosphere.…”

Section: Detection Of Magnetic Fields On Exoplanets?mentioning

confidence: 99%

Magnetodynamo lifetimes for rocky, Earth‐mass exoplanets with contrasting mantle convection regimes

2013

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Abstract. We used a thermal model of an iron core to calculate magnetodynamo evolution in Earth-mass rocky planets to determine the sensitivity of dynamo lifetime and intensity to planets with different mantle tectonic regimes, surface temperatures, and core properties. The heat flow at the core-mantle boundary (CMB) is derived from numerical models of mantle convection with a viscous/pseudo-plastic rheology that captures the phenomenology of plate-like tectonics. Our thermal evolution models predict a longlived (∼8 Gyr) field for Earth and similar dynamo evolution for Earth-mass exoplanets with plate tectonics. Both elevated surface temperature and pressure-dependent mantle viscosity reduce the CMB heat flow but produce only slightly longer-lived dynamos (∼8-9.5 Gyr). Single-plate ("stagnant lid") planets with relatively low CMB heat flow produce long-lived (∼10.5 Gyr) dynamos. These weaker dynamos can cease for several billions of years and subsequently reactivate due to the additional entropy production associated with inner core growth, a possible explanation for the absence of a magnetic field on present-day Venus. We also show that dynamo operation is sensitive to the initial temperature, size, and solidus of a planet's core. These dependencies would severely challenge any attempt to distinguish exoplanets with plate tectonics and stagnant lids based on the presence or absence of a magnetic field.

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“…In principle radio observations could be used to determine the magnetic field strength of hot Jupiters, but most host stars have not been detected in radio observations so far (Sirothia et al 2014). In particular, Lecavelier Des Etangs et al (2011) presented observations with the Giant Metrewave Radio Telescope resulting in upper limits for the meter wavelength radio emission from HD 209458 and HD 189733. With certain assumptions, the nondetections indicate upper limits for the planetary magnetic field strength of only few times that of Jupiter.…”

Section: Introductionmentioning

confidence: 99%

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

Salz

Schneider

Czesla

et al. 2015

A&A

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Giant gas planets in close proximity to their host stars experience strong irradiation. In extreme cases photoevaporation causes a transonic, planetary wind and the persistent mass loss can possibly affect the planetary evolution. We have identified nine hot Jupiter systems in the vicinity of the Sun, in which expanded planetary atmospheres should be detectable through Lyα transit spectroscopy according to predictions. We use X-ray observations with Chandra and XMM-Newton of seven of these targets to derive the highenergy irradiation level of the planetary atmospheres and the resulting mass loss rates. We further derive improved Lyα luminosity estimates for the host stars including interstellar absorption. According to our estimates WASP-80 b, WASP-77 b, and WASP-43 b experience the strongest mass loss rates, exceeding the mass loss rate of HD 209458 b, where an expanded atmosphere has been confirmed. Furthermore, seven out of nine targets might be amenable to Lyα transit spectroscopy. Finally, we check the possibility of angular momentum transfer from the hot Jupiters to the host stars in the three binary systems among our sample, but find only weak indications for increased stellar rotation periods of WASP-77 and HAT-P-20.

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GMRT search for 150 MHz radio emission from the transiting extrasolar planets HD 189733 b and HD 209458 b

Cited by 45 publications

References 47 publications

An Ultraviolet Investigation of Activity on Exoplanet Host Stars

An Ultraviolet Investigation of Activity on Exoplanet Host Stars

Magnetodynamo lifetimes for rocky, Earth‐mass exoplanets with contrasting mantle convection regimes

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

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