Revisiting the Iconic Spitzer Phase Curve of 55 Cancri e: Hotter Dayside, Cooler Nightside, and Smaller Phase Offset

Abstract Thermal phase curves of short-period exoplanets provide the best constraints on atmospheric dynamics and heat transport in their atmospheres. The published Spitzer Space Telescope curve 55 Cancri e, an ultra-short-period super-Earth, exhibits a large offset suggesting significant eastward recirculation, unexpected such hot planet. We present our rereduction analysis these iconic observations using open source modular Phase Curve Analysis pipeline. In particular, we attempt to reproduce same instrument detrending scheme as original authors. retrieve dayside temperature ( T day = 3771 − 520 + 669 K), nightside ${T}_{\mathrm{night}\,}\lt 1649$?> night < 1649 K at 2σ), longitudinal planet's spot, quantify how they depend reduction detrending. Our reanalysis suggests that e has negligible spot $-{12}_{-18}^{+21}$?> 12 18 21 degrees east. small cool are consistent with poor expected planets. high 4.5 μ m brightness is qualitatively SiO emission from inverted rock vapor atmosphere.