Archival Legacy Investigations of Circumstellar Environments: Overview and First Results

TL;DR

The ALICE project re-processed archival HST-NICMOS data to discover new circumstellar structures and potential substellar companions, providing valuable insights into planetary formation environments and developing methods for future space telescopes.

Contribution

This work introduces advanced PSF subtraction techniques applied to archival data, revealing new debris disks and candidates, and establishes standards for high-level science products for future missions.

Findings

Discovered five new spatially resolved debris disks.

Detected several candidate substellar companions.

Developed PSF subtraction methods applicable to future missions.

Abstract

We are currently conducting a comprehensive and consistent re-processing of archival HST-NICMOS coronagraphic surveys using advanced PSF subtraction methods, entitled the Archival Legacy Investigations of Circumstellar Environments program (ALICE, HST/AR 12652). This virtual campaign of about 400 targets has already produced numerous new detections of previously unidentified point sources and circumstellar structures. We present five newly spatially resolved debris disks revealed in scattered light by our analysis of the archival data. These images provide new views of material around young solar-type stars at ages corresponding to the period of terrestrial planet formation in our solar system. We have also detected several new candidate substellar companions, for which there are ongoing followup campaigns (HST/WFC3 and VLT/SINFONI in ADI mode). Since the methods developed as part of ALICE are directly applicable to future missions (JWST, AFTA coronagraph) we emphasize the importance of devising optimal PSF subtraction methods for upcoming coronagraphic imaging missions. We describe efforts in defining direct imaging high-level science products (HLSP) standards that can be applicable to other coronagraphic campaigns, including ground-based (e.g., Gemini Planet Imager), and future space instruments (e.g., JWST). ALICE will deliver a first release of HLSPs to the community through the MAST archive at STScI in 2014.