Transmission spectroscopy and Rossiter-McLaughlin measurements of the young Neptune orbiting AU Mic
Article
Article Title | Transmission spectroscopy and Rossiter-McLaughlin measurements of the young Neptune orbiting AU Mic |
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ERA Journal ID | 1050 |
Article Category | Article |
Authors | Palle, E. (Author), Oshagh, M. (Author), Casasayas-Barris, N. (Author), Hirano, T. (Author), Stangret, M. (Author), Luque, R. (Author), Strachan, J. (Author), Gaidos, E. (Author), Anglada-Escude, G. (Author), Plavchan, P. (Author) and Addison, B. (Author) |
Journal Title | Astronomy and Astrophysics: a European journal |
Journal Citation | 643, pp. 1-10 |
Article Number | A25 |
Number of Pages | 10 |
Year | 2020 |
Publisher | EDP Sciences |
Place of Publication | France |
ISSN | 0004-6361 |
1432-0746 | |
Digital Object Identifier (DOI) | https://doi.org/10.1051/0004-6361/202038583 |
Web Address (URL) | https://www.aanda.org/articles/aa/abs/2020/11/aa38583-20/aa38583-20.html |
Abstract | AU Mic b is a Neptune-sized planet on an 8.47-day orbit around the nearest pre-main sequence (~20 Myr) star to the Sun, the bright (V = 8.81) M dwarf AU Mic. The planet was preliminary detected in Doppler radial velocity time series and recently confirmed to be transiting with data from the TESS mission. AU Mic b is likely to be cooling and contracting and might be accompanied by a second, more massive planet, in an outer orbit. Here, we present the observations of the transit of AU Mic b using ESPRESSO on the Very Large Telescope. We obtained a high-resolution time series of spectra to measure the Rossiter-McLaughlin effect, to constrain the spin-orbit alignment of the star and planet, and to simultaneously attempt to retrieve the planet's atmospheric transmission spectrum. These observations allowed us to study, for the first time, the early phases of the dynamical evolution of young systems. We applied different methodologies to derive the spin-orbit angle of AU Mic b, and all of them retrieve values consistent with the planet being aligned with the rotation plane of the star. We determined a conservative spin-orbit angle λ value of -2.96-10.30+10.44 degrees, indicative that the formation and migration of the planets of the AU Mic system occurred within the disc. Unfortunately, and despite the large signal-to-noise ratio of our measurements, the degree of stellar activity prevented us from detecting any features from the planetary atmosphere. In fact, our results suggest that transmission spectroscopy for recently formed planets around active young stars is going to remain very challenging, if at all possible, for the near future. |
Keywords | planets and satellites: atmospheres - techniques: radial velocities -; planets and satellites: formation - planets and satellites: individual:; Au Mic; Astrophysics - Earth and Planetary Astrophysics; Astrophysics -; Solar and Stellar Astrophysics |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Institute of Astrophysics of the Canary Islands, Spain |
University of La Laguna, Spain | |
Tokyo Institute of Technology, Japan | |
Queen Mary University of London, United Kingdom | |
University of Hawaii, United States | |
Institute of Space Sciences, Spain | |
George Mason University, United States | |
University of Southern Queensland | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q6132/transmission-spectroscopy-and-rossiter-mclaughlin-measurements-of-the-young-neptune-orbiting-au-mic
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