Core Concepts
Observations of the rocky exoplanet LTT 1445A b using JWST's MIRI/LRS instrument reveal a dayside brightness temperature consistent with a dark, rocky surface, suggesting the planet lacks a thick CO2 atmosphere.
Stats
LTT 1445A b has a radius of 1.34 +0.11/-0.06 R⊕ and a mass of 2.73 +0.25/-0.23 M⊕.
The planet receives an instellation of 5.7+1.3/-1.1 S⊕, comparable to Mercury.
The observed broadband secondary eclipse depth is 41 ± 9 ppm.
The planet's dayside brightness temperature is constrained to 525 ± 15 K.
The temperature ratio R = Tday,obs/Tmax is 0.952 ± 0.057.