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Arxiv: JWST COMPASS: NIRSpec/G395H Transmission Observations of the Super-Earth TOI-776b Published: 1/24/2025 6:08:00 PM Updated: 1/24/2025 6:08:00 PM

Paper abstract: We present two transit observations of the ~520K, 1.85R_\oplus,4.0M_\oplus super-Earth TOI-776b with JWST NIRSpec/G395H, resulting in a2.8-5.2\mum transmission spectrum. Producing reductions using the ExoTiC-JEDIand Eureka! pipelines, we obtain a median transit depth precision of 34ppm forboth visits and both reductions in spectroscopic channels 30 pixels wide(~0.02\mum). We find that our independent reductions produce consistenttransmission spectra, however, each visit shows differing overall structure.For both reductions, a flat line is preferred for Visit 1 while a flat linewith an offset between the NRS1 and NRS2 detectors is preferred for Visit 2;however, we are able to correct for this offset during our modeling analysisfollowing methods outlined in previous literature. Using picaso forward models,we can rule out metallicities up to at least 100\times solar with an opaquepressure of 10^{-3} bar to >=3\sigma in all cases, however, the exactlower limit varies between the visits, with Visit 1 ruling out<~100\times solar while the lower limits for Visit 2 extend beyond~350\times solar. Our results add to the growing list of super-Earthatmospheric constraints by JWST, which provide critical insight into thediversity and challenges of characterizing terrestrial planets.