Planet parameters from IRAC measurements

Combined with our secondary eclipse observations, these phase-curve measurements imply a 4.5{mu}m dayside brightness temperature of 1800{+/-}120K, a nightside brightness temperature of 700{+/-}430K (<1350K at 2{sigma} confidence), and a day-night brightness temperature contrast of 1110{+/-}460K. We compare our data to the predictions of 3D general circulation models calculated at multiple metallicity levels and to similar observations of hot Jupiters experiencing similar levels of stellar irradiation.

Though not conclusive, our measurement of its small 4.5{mu}m phase offset, the relatively large amplitude of the phase variation, and the qualitative differences between our target's dayside emission spectrum and those of hot Jupiters of similar temperatures all suggest a supersolar atmospheric metallicity for LTT9779b, as might be expected given its size and mass. Finally, we measure the planet's transits at both 3.6{mu}m and 4.5{mu}m, providing a refined ephemeris (P=0.79207022{+/-}0.00000069days, T0=2458783.51636{+/-}0.00027, BJDTDB) that will enable efficient scheduling of future observations to further characterize the atmosphere of this intriguing planet.