Non-detection of Contamination by Stellar Activity in the Spitzer Transit Light Curves of TRAPPIST-1

August 2018 • 2018ApJ...863L..32M

Authors • Morris, Brett M. • Agol, Eric • Hebb, Leslie • Hawley, Suzanne L. • Gillon, MichaĆ«l • Ducrot, Elsa • Delrez, Laetitia • Ingalls, James • Demory, Brice-Olivier

Abstract • We apply the transit light curve self-contamination technique of Morris et al. to search for the effect of stellar activity on the transits of the ultracool dwarf TRAPPIST-1 with 2018 Spitzer photometry. The self-contamination method fits the transit light curves of planets orbiting spotted stars, allowing the host star to be a source of contaminating positive or negative flux that influences the transit depths but not the ingress/egress durations. We find that none of the planets show statistically significant evidence for self-contamination by bright or dark regions of the stellar photosphere. However, we show that small-scale magnetic activity, analogous in size to the smallest sunspots, could still be lurking undetected in the transit photometry.


IPAC Authors

Jim Ingalls

Associate Scientist