H: Upper limit
|
HST STIS | Hubble's Multi-Year Search for Exospheres in the TRAPPIST-1 System Reveals Frequent Microflares2025, David Berardo, Julien de Wit et al. |
Lya is not very constrained due to the effect of microflares in the out-of-transit baseline, transit depth <20% at 5σ |
He: No detection
|
G-B: High resolution IR | Non-detection of Helium in the upper atmospheres of TRAPPIST-1b, e and f2021, Vigneshwaran Krishnamurthy, Teruyuki Hirano et al. |