EXPRES. III. Photometry & RVel of eps Eridani

DOI

The distortions of absorption line profiles caused by photospheric brightness variations on the surfaces of cool, main-sequence stars can mimic or overwhelm radial velocity (RV) shifts due to the presence of exoplanets. The latest generation of precision RV spectrographs aims to detect velocity amplitudes <~10cm/s, but requires mitigation of stellar signals. Statistical techniques are being developed to differentiate between Keplerian and activity-related velocity perturbations. Two important challenges, however, are the interpretability of the stellar activity component as RV models become more sophisticated, and ensuring the lowest-amplitude Keplerian signatures are not inadvertently accounted for in flexible models of stellar activity. For the K2V exoplanet host {epsilon}Eridani, we separately used ground-based photometry to constrain Gaussian processes for modeling RVs and TESS photometry with a light-curve inversion algorithm to reconstruct the stellar surface. From the reconstructions of TESS photometry, we produced an activity model that reduced the rms scatter in RVs obtained with EXPRES from 4.72 to 1.98m/s. We present a pilot study using the CHARA Array and MIRC-X beam combiner to directly image the starspots seen in the TESS photometry. With the limited phase coverage, our spot detections are marginal with current data but a future dedicated observing campaign should allow for imaging, as well as allow the stellar inclination and orientation with respect to the debris disk to be definitively determined. This work shows that stellar surface maps obtained with high-cadence, time-series photometric and interferometric data can provide the constraints needed to accurately reduce RV scatter.

Identifier
DOI http://doi.org/10.26093/cds/vizier.51630019
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/AJ/163/19
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/163/19
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/163/19
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/AJ/163/19
Provenance
Creator Roettenbacher R.M.; Cabot S.H.C.; Fischer D.A.; Monnier J.D.,Henry G.W.,Harmon R.O.; Korhonen H.; Brewer J.M.; Llama J.; Petersburg R.R.; Zhao L.L.,Kraus S.; Le Bouquin J.-B.; Anugu N.; Davies C.L.; Gardner T.,Lanthermann C.; Schaefer G.; Setterholm B.; Clark C.A.; Jorstad S.G.,Kuehn K.; Levine S.
Publisher CDS
Publication Year 2022
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Exoplanet Astronomy; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy