Ground-based photometry of the 21-day Neptune HD106315c

Abstract

Space-based transit surveys such as K2 and TESS allow the detection of small transiting planets with orbital periods beyond 10 days. Few of these warm Neptunes are currently known around stars bright enough to allow for detailed follow-up observations dedicated to their atmospheric characterization. The 21-day period and 3.95 $R_{\oplus }$ planet HD106315c has been discovered based on the observation of two of its transits by K2. We have observed HD106315 using the 1.2m Euler telescope equipped with the EulerCam camera on two instances to confirm the transit using broad band photometry and refine the planetary period. Based on two observed transits of HD106315c, we detect its $\sim$1 mmag transit and obtain a precise measurement of the planetary ephemerids, which are critical for planning further follow-up observations. We have used the attained precision together with the predicted yield from the TESS mission to evaluate the potential for ground-based confirmation of Neptune-sized planets found by TESS. We find that 1-meter-class telescopes on the ground equipped with precise photometers could substantially contribute to the follow-up of 162 TESS candidates orbiting stars with magnitudes of $V\le 14$. Out of these, 74 planets orbit stars with $V\le 12$ and 12 planets orbit $V\le 10$, which makes these candidates high-priority objects for atmospheric characterization with high-end instrumentation.

Published in A&A letters, 4 pages, 3 figures

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Cited by in corpus (6)

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• Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) VI. Non-detection of sodium with HARPS on the bloated super-Neptune WASP-127b
• ARES IV: Probing the atmospheres of the two warm small planets HD 106315 c and HD 3167 c with the HST/WFC3 camera
• Physical Parameters of the Multi-Planet Systems HD 106315 and GJ 9827
• Detection capability of ground-based meter-sized telescopes for shallow exoplanet transits