The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems IX: A Multi-Wavelength Framework for Source Characterization in JWST Coronagraphic Imaging of the HIP 65426 System

@misc{bruinsma2026jwst,
  title = {{The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems IX: A Multi-Wavelength Framework for Source Characterization in JWST Coronagraphic Imaging of the HIP 65426 System}},
  author = {Evelyn L. Bruinsma and Aarynn L. Carter and Sasha Hinkley and Beth A. Biller and Andy Skemer and William O. Balmer and Andrew D. James and Ellis X. Bogat and Ben J. Sutlieff and Michael Poon and Mathilde Mâlin and Katie A. Crotts and Genaro Suárez and Eileen Gonzales and Klaus Subbotina Stephenson and Markus Janson and Motohide Tamura and Raphaël Bendahan-West and Giovanni M. Strampelli and Michael R. Meyer and Emily Rickman and Julien H. Girard and Kellen Lawson and Alice Zurlo and Cecilia Lazzoni and Christopher A. Theissen and Thomas Henning and Pengyu Liu and Mark C. Wyatt and Isabel Rebollido and Aiza Kenzhebekova},
  howpublished = {arXiv},
  year = {2026},
  month = nov,
  doi = {10.48550/arxiv.2611.07034},
  eprint = {2611.07034},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2611.07034},
}

TY  - UNPB
TI  - The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems IX: A Multi-Wavelength Framework for Source Characterization in JWST Coronagraphic Imaging of the HIP 65426 System
AU  - Evelyn L. Bruinsma
AU  - Aarynn L. Carter
AU  - Sasha Hinkley
AU  - Beth A. Biller
AU  - Andy Skemer
AU  - William O. Balmer
AU  - Andrew D. James
AU  - Ellis X. Bogat
AU  - Ben J. Sutlieff
AU  - Michael Poon
AU  - Mathilde Mâlin
AU  - Katie A. Crotts
AU  - Genaro Suárez
AU  - Eileen Gonzales
AU  - Klaus Subbotina Stephenson
AU  - Markus Janson
AU  - Motohide Tamura
AU  - Raphaël Bendahan-West
AU  - Giovanni M. Strampelli
AU  - Michael R. Meyer
AU  - Emily Rickman
AU  - Julien H. Girard
AU  - Kellen Lawson
AU  - Alice Zurlo
AU  - Cecilia Lazzoni
AU  - Christopher A. Theissen
AU  - Thomas Henning
AU  - Pengyu Liu
AU  - Mark C. Wyatt
AU  - Isabel Rebollido
AU  - Aiza Kenzhebekova
PY  - 2026
DA  - 2026/11/04
PB  - arXiv
DO  - 10.48550/arxiv.2611.07034
UR  - https://arxiv.org/abs/2611.07034
AB  - We present an updated analysis of the JWST coronagraphic imaging data of the HIP 65426 system. We aim to search for and characterize potential planetary companions as well as provide updated astrometry and photometry for the known exoplanet HIP 65426 b following updates to the JWST and spaceKLIP pipelines. Our measured photometry and astrometry show significant differences to those in Carter et al. (2023) but are consistent to within 2.2σ in separation, 1.5σ in position angle, and 3.7σ in flux. Our results indicate that pipeline updates have changed the photometry and astrometry significantly in some filters, especially in terms of observed flux. We see the greatest changes in separation in F444W and F1550C, position angle in F250M, and flux in F250M, F300M, F410M, F1140C, and F1550C. The SED of HIP 65426 b remains consistent with a young, giant planet best fit by models with a cloudy atmosphere and an effective temperature estimate of ~1436 K. Using both NIRCam and MIRI data, we identified 21 candidate companion sources in addition to the known planet. Of the 21 sources, 13 were attributed to astrophysical sources with eight background stars, four galaxies, one unknown, and zero planets. While one of these sources was detected in Chauvin et al. (2017), the remaining point sources were undetected in previous ground-based observations, which makes this work an initial epoch of astrometry for these objects. One galaxy in particular appears as a point source in MIRI but is highly extended in NIRCam and exposes a potential drawback to single-epoch MIRI imaging in a blind search for companions.
ER  -