An ESPRESSO view of HD 189733 system. Broadband transmission spectrum, differential rotation, and system architecture
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2023
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| author | Cristo, E. Borges, E. Esparza Santos, N. C. Demangeon, O. Palle, E. Psaridi, A. Bourrier, V. Faria, J. P. Allart, R. Silva, T. Azevedo Borsa, F. Alibert, Y. Figueira, P. Hernández, J. I. González Lendl, M. Lillo-Box, J. Curto, G. Lo Di Marcantonio, P. Martins, C. J. A. P. Nunes, N. J. Pepe, F. Seidel, J. V. Sousa, S. G. Sozzetti, A. Stangret, M. Mascareño, A. Suárez Tabernero, H. M. Osorio, M. R. Zapatero |
| author_facet | Cristo, E. Borges, E. Esparza Santos, N. C. Demangeon, O. Palle, E. Psaridi, A. Bourrier, V. Faria, J. P. Allart, R. Silva, T. Azevedo Borsa, F. Alibert, Y. Figueira, P. Hernández, J. I. González Lendl, M. Lillo-Box, J. Curto, G. Lo Di Marcantonio, P. Martins, C. J. A. P. Nunes, N. J. Pepe, F. Seidel, J. V. Sousa, S. G. Sozzetti, A. Stangret, M. Mascareño, A. Suárez Tabernero, H. M. Osorio, M. R. Zapatero |
| contents | The development of state-of-the-art spectrographs has ushered in a new era in the detection and characterization of exoplanetary systems. Our objective is to utilize the high-resolution and precision capabilities of the ESPRESSO instrument to detect and measure the broad-band transmission spectrum of HD 189733b's atmosphere. Additionally, we aim to employ an improved Rossiter-McLaughlin model to derive properties related to the velocity fields of the stellar surface and to constrain the orbital architecture.
Our results demonstrate a high degree of precision in fitting the observed radial velocities during transit using the improved modeling of the Rossiter-McLaughlin effect. We tentatively detect the effect of differential rotation with a confidence level of $93.4 \%$ when considering a rotation period within the photometric literature values, and $99.6\%$ for a broader range of rotation periods. For the former, the amplitude of differential rotation ratio suggests an equatorial rotation period of $11.45\pm 0.09$ days and a polar period of $14.9\pm 2$. The addition of differential rotation breaks the latitudinal symmetry, enabling us to measure the true spin-orbit angle $ ψ\approx 13.6 \pm 6.9 ^\circ$ and the stellar inclination axis angle $ i_{\star} \approx 71.87 ^{+6.91^\circ}_{-5.55^\circ}$. Moreover, we determine a sub-solar amplitude of the convective blueshift velocity $V_{CB}$ $\approx$ $-211 ^{+69} _{-61}$ m$\,$s$ ^{-1}$, which falls within the expected range for a K-dwarf host star and is compatible with both runs.
Finally, we successfully retrieved the transmission spectrum of HD 189733b from the high-resolution ESPRESSO data. We observe a significant decrease in radius with increasing wavelength, consistent with the phenomenon of super-Rayleigh scattering. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_06681 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | An ESPRESSO view of HD 189733 system. Broadband transmission spectrum, differential rotation, and system architecture Cristo, E. Borges, E. Esparza Santos, N. C. Demangeon, O. Palle, E. Psaridi, A. Bourrier, V. Faria, J. P. Allart, R. Silva, T. Azevedo Borsa, F. Alibert, Y. Figueira, P. Hernández, J. I. González Lendl, M. Lillo-Box, J. Curto, G. Lo Di Marcantonio, P. Martins, C. J. A. P. Nunes, N. J. Pepe, F. Seidel, J. V. Sousa, S. G. Sozzetti, A. Stangret, M. Mascareño, A. Suárez Tabernero, H. M. Osorio, M. R. Zapatero Earth and Planetary Astrophysics The development of state-of-the-art spectrographs has ushered in a new era in the detection and characterization of exoplanetary systems. Our objective is to utilize the high-resolution and precision capabilities of the ESPRESSO instrument to detect and measure the broad-band transmission spectrum of HD 189733b's atmosphere. Additionally, we aim to employ an improved Rossiter-McLaughlin model to derive properties related to the velocity fields of the stellar surface and to constrain the orbital architecture. Our results demonstrate a high degree of precision in fitting the observed radial velocities during transit using the improved modeling of the Rossiter-McLaughlin effect. We tentatively detect the effect of differential rotation with a confidence level of $93.4 \%$ when considering a rotation period within the photometric literature values, and $99.6\%$ for a broader range of rotation periods. For the former, the amplitude of differential rotation ratio suggests an equatorial rotation period of $11.45\pm 0.09$ days and a polar period of $14.9\pm 2$. The addition of differential rotation breaks the latitudinal symmetry, enabling us to measure the true spin-orbit angle $ ψ\approx 13.6 \pm 6.9 ^\circ$ and the stellar inclination axis angle $ i_{\star} \approx 71.87 ^{+6.91^\circ}_{-5.55^\circ}$. Moreover, we determine a sub-solar amplitude of the convective blueshift velocity $V_{CB}$ $\approx$ $-211 ^{+69} _{-61}$ m$\,$s$ ^{-1}$, which falls within the expected range for a K-dwarf host star and is compatible with both runs. Finally, we successfully retrieved the transmission spectrum of HD 189733b from the high-resolution ESPRESSO data. We observe a significant decrease in radius with increasing wavelength, consistent with the phenomenon of super-Rayleigh scattering. |
| title | An ESPRESSO view of HD 189733 system. Broadband transmission spectrum, differential rotation, and system architecture |
| topic | Earth and Planetary Astrophysics |
| url | https://arxiv.org/abs/2310.06681 |