The PEPSI Exoplanet Transit Survey. III: The detection of FeI, CrI and TiI in the atmosphere of MASCARA-1 b through high-resolution emission spectroscopy

TL;DR

This study successfully detected FeI, CrI, and TiI in the atmosphere of MASCARA-1 b using high-resolution emission spectroscopy, confirming atmospheric presence despite previous non-detections in transmission.

Contribution

First detection of atomic species FeI, CrI, and TiI in MASCARA-1 b's atmosphere via high-resolution emission spectroscopy, highlighting the method's effectiveness.

Findings

Detected FeI, CrI, and TiI with S/N of 7, 4, and 5 respectively.

Confirmed systemic velocity of ~13 km/s and radial velocity semi-amplitude of ~200 km/s.

Validated atmospheric presence around MASCARA-1 b through emission spectroscopy.

Abstract

Hot giant planets like MASCARA-1 b are expected to have thermally inverted atmospheres, that makes them perfect laboratory for the atmospheric characterization through high-resolution spectroscopy. Nonetheless, previous attempts of detecting the atmosphere of MASCARA-1 b in transmission have led to negative results. In this paper we aim at the detection of the optical emission spectrum of MASCARA-1 b. We used the high-resolution spectrograph PEPSI to observe MASCARA-1 (spectral type A8) near the secondary eclipse of the planet. We cross-correlated the spectra with synthetic templates computed for several atomic and molecular species. We obtained the detection of FeI, CrI and TiI in the atmosphere of MASCARA-1 b with a S/N ~7, 4 and 5 respectively, and confirmed the expected systemic velocity of ~13 km/s and the radial velocity semi-amplitude of MASCARA-1 b of ~200 km/s. The detection of Ti is of particular importance in the context of the recently proposed Ti cold-trapping below a certain planetary equilibrium temperature. We confirm the presence of an the atmosphere around MASCARA-1 b through emission spectroscopy. We conclude that the atmospheric non detection in transmission spectroscopy is due to the high gravity of the planet and/or to the overlap between the planetary track and its Doppler shadow.