Wide Field Planetary Camera 2 Observations of Proxima Centauri: No Evidence of the Possible Substellar Companion

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Two-epoch observations of Proxima Centauri using the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) are reported. Exposures of 10 and 40 s were recorded through the F1042M filter (λc ≈ 1 μm), permitting examination of the circumstellar region beyond 009 from Proxima Cen. No evidence of a substellar companion within 085 of Proxima Cen is seen, which counters the recently reported detection of a faint feature by Schultz et al. using HST's Faint Object Spectrograph (FOS). A feature in the WFPC2 images having a relative brightness and a separation comparable to those of the FOS feature would have been detected with a signal-to-noise ratio of ~22. Moreover, if the FOS feature were a substellar companion, it should have appeared in our F1042M images to be about 3.7 mag fainter than Proxima Cen. Inspection of deep WFPC2 images of Proxima Cen through three filters indicates that the FOS feature is not a background object. Local enhancements of WFPC2's point-spread function suggest a possible instrumental origin for the FOS feature, but the singularity and apparent motion of the FOS feature complicate this notion.