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Planetary Transits at Radio Wavelengths: Secondary Eclipses of Hot Jupiter Extended Atmospheres

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Autor(es):
Selhorst, Caius L. [1] ; Barbosa, Cassio L. [2] ; Simoes, Paulo [3, 4] ; Vidotto, Aline A. [5] ; Valio, Adriana [4]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Univ Cidade Sao Paulo, Univ Cruzeiro do Sul, NAT Nucl Astrofis, Sao Paulo, SP - Brazil
[2] Ctr Univ FEI, Dept Fis, Sao Bernardo Do Campo, SP - Brazil
[3] Univ Glasgow, SUPA Sch Phys & Astron, Glasgow G12 8QQ, Lanark - Scotland
[4] Univ Presbiteriana Mackenzie, CRAAM, BR-01302907 Sao Paulo, SP - Brazil
[5] Univ Dublin, Trinity Coll Dublin, Sch Phys, Dublin 2 - Ireland
Número total de Afiliações: 5
Tipo de documento: Artigo Científico
Fonte: ASTROPHYSICAL JOURNAL; v. 895, n. 1 MAY 2020.
Citações Web of Science: 0
Resumo

When a planet transits in front of its host star, a fraction of its light is blocked, decreasing the observed flux from the star. The same is expected to occur when observing the stellar radio flux. However, at radio wavelengths, the planet also radiates, depending on its temperature, and thus modifies the transit depths. We explore this scenario simulating the radio lightcurves of transits of hot Jupiters, Kepler-17b, and WASP-12b, around solar-like stars. We calculated the bremsstrahlung radio emission at 17, 100, and 400 GHz originating from the star, considering a solar atmospheric model. The planetary radio emission was calculated modeling the planets in two scenarios: as a blackbody or with a dense and hot extended atmosphere. In both cases the planet radiates and contributes to the total radio flux. For a blackbody planet, the transit depth is in the order of 2%-4% and it is independent of the radio frequency. Hot Jupiters planets with atmospheres appear bigger and brighter in radio, thus having a larger contribution to the total flux of the system. Therefore, the transit depths are larger than in the case of blackbody planets, reaching up to 8% at 17 GHz. Also the transit depth is frequency-dependent. Moreover, the transit caused by the planet passing behind the star is deeper than when the planet transits in front of the star, being as large as 18% at 400 GHz. In all cases, the contribution of the planetary radio emission to the observed flux is evident when the planet transits behind the star. (AU)

Processo FAPESP: 19/03301-8 - Observação e modelagem de regiões ativas solares e estelares em ondas rádio mm/sub-mm
Beneficiário:Caius Lucius Selhorst
Linha de fomento: Auxílio à Pesquisa - Regular
Processo FAPESP: 13/10559-5 - Investigação de fenômenos de altas energias e plasmas astrofísicos: teoria, simulações numéricas, observações e desenvolvimento de instrumentação para o Cherenkov Telescope Array (CTA)
Beneficiário:Elisabete Maria de Gouveia Dal Pino
Linha de fomento: Auxílio à Pesquisa - Temático