TESS re-observes the young multi-planet system TOI-451: refined ephemeris and activity evolution

TL;DR

This paper refines the orbital parameters of the young multi-planet system TOI-451 using new TESS data, and investigates stellar activity evolution through Gaussian Process modeling of light curve variations.

Contribution

It provides improved ephemeris for the planets and analyzes stellar activity changes over TESS observation cycles.

Findings

Refined planetary ephemerides for TOI 451 b, c, and d.

Detected changes in stellar active regions between observation cycles.

Enhanced planning for future follow-up observations.

Abstract

We present a new analysis of the light curve of the young planet-hosting star TOI 451 in the light of new observations from TESS Cycle 3. Our joint analysis of the transits of all three planets, using all available TESS data, results in an improved ephemeris for TOI 451 b and TOI 451 c, which will help to plan follow-up observations. The updated mid-transit times are $\textrm{BJD}-2,457\,000=$ $1410.9896_{ - 0.0029 }^{ + 0.0032 }$, $1411.7982_{-0.0020}^{+0.0022}$, and $1416.63407_{-0.00100}^{+0.00096}$ for TOI 451 b, c, and d, respectively, and the periods are $1.8587028_{-10e-06}^{+08e-06}$, $9.192453_{-3.3e-05}^{+4.1e-05}$, and $16.364932_{-3.5e-05}^{+3.6e-05 }$ days. We also model the out-of-transit light curve using a Gaussian Process with a quasi-periodic kernel and infer a change in the properties of the active regions on the surface of TOI 451 between TESS Cycles 1 and 3.