The PEPSI Exoplanet Transit Survey (PETS). V: New Na D transmission spectra indicate a quieter atmosphere on HD 189733b
Abstract
Absorption lines from exoplanet atmospheres observed in transmission allow us to study atmospheric characteristics such as winds. We present a new high-resolution transit time-series of HD 189733b, acquired with the PEPSI instrument at the LBT and analyze the transmission spectrum around the Na D lines. We model the spectral signature of the RM-CLV-effect using synthetic PHOENIX spectra based on spherical LTE atmospheric models. We find a Na D absorption signature between the second and third contact but not during the ingress and egress phases, which casts doubt on the planetary origin of the signal. Presupposing a planetary origin of the signal, the results suggest a weak day-to-nightside streaming wind in the order of 0.7 km s-1 and a moderate super-rotational streaming wind in the order of 3-4 km s-1, challenging claims of prevailing strong winds on HD 189733b.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 2024
- DOI:
- 10.1093/mnras/stae1097
- arXiv:
- arXiv:2404.13586
- Bibcode:
- 2024MNRAS.tmp.1127K
- Keywords:
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- exoplanet;
- exoplanet atmosphere;
- transmission spectroscopy;
- synthetic transmission spectra;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- Accepted for publication in Monthly Notices of the Royal Astronomical Society