WIDE-FIELD PLANETARY CAMERA-2 OBSERVATIONS OF PROXIMA CENTAURI - NO EVIDENCE OF THE POSSIBLE SUBSTELLAR COMPANION

Two-epoch observations of Proxima Centauri using the Hubble Space Tele scope (HST) Wide Field Planetary Camera 2 (WFPC2) are reported. Exposu res of 10 and 40 s were recorded through the F1042M filter (lambda(c) approximate to 1 mu m), permitting examination of the circumstellar re gion beyond 0.'' 09 from Proxima Cen. No evidence of a substellar comp anion within 0.'' 85 of Proxima Cen is seen, which counters the recent ly 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 simi lar to 22. Moreover, if the FOS feature were a substellar companion, i t should have appeared in our F1042M images to be about 3.7 mag fainte r than Proxima Cen. Inspection of deep WFPC2 images of Proxima Cen thr ough 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.