Overview of the special optics for high-contrast imaging (HCI) with JWST
Three JWST instruments offer various HCI optics to suppress diffracted light from the host and thereby make companion sources—both point and extended—more observable.
- NIRCam coronagraphic imaging: 5 Lyot coronagraphs (LYOTs) (3 round, 2 bars).
All allowed NIRCam coronagraphic configurations are listed here.
NIRCam LYOTs with round coronagraphic masks (occulters) work best in narrow and medium bands centered at 1.92, 3.23, and 4.35 µm.
NIRCam LYOTs with bar-shaped occulters work best in narrow and medium bands in the ranges 1.7–2.2 µm and 2.4–5 µm.
- MIRI coronagraphic imaging: 1 LYOT and 3 4-quadrant phase-mask coronagraphs (4QPMCs).
MIRI 4QPMs work only in narrow bands centered at 10.65, 14.40, and 15.50 µm.
MIRI LYOT works only in a broad band centered at 23 µm.
- NIRISS aperture masking Interferometry: 1 aperture masking interferometer (AMI).
NIRISS/AMI works best with medium bands centered at 3.8, 4.3, and 4.8 µm.
NIRISS’s 65-mas pixels satisfy the Nyquist criterion at 4 µm wavelength and performance at shorter wavelengths is reduced. Nevertheless, because the wide filter centered at 2.77 µm spans a deep absorption feature of water, its use may be particularly relevant for exoplanetary research.
In addition, HCI can be carried out using basic imaging modes of the observatory (Rajan et al. 2015, Durcan, Janson, and Carson 2016), as well as using IFU strategies similar to Konopacky et al. (2013). These modes are not yet covered in the documentation.
Lyot coronagraph (LYOT)
If the apparent separation between the feature of interest and the host is greater than IWA, companion light passes the occulter, and—after losing a bit of light on the Lyot stop—the light from the feature of interest reaches the detector. On JWST, NIRCam has 5 sets of LYOT optics (3 with round and 2 with bar-shaped occulters), and MIRI has 1 LYOT, with a round occulter. (See Figure 2.)
Four-quadrant phase-mask coronagraph (4QPMC)
Aperture-masking interferometer (AMI)
NIRCam Coronagraphic Imaging
MIRI Coronagraphic Imaging
NIRISS Aperture Masking Interferometry
NIRCam Coronagraphic Occulting Masks and Lyot Stops
MIRI Coronagraph Masks
NIRCam Filters for Coronagraphy
MIRI Filters and Dispersers
High contrast imaging articles
Beichman, C. A., et al. 2010, PASP, 122:162
Imaging Young Giant Planets from Ground and Space
Boccaletti, A., et al. 2015, PASP, 127, 633
The Mid-Infrared Instrument for the James Webb Space Telescope, V: Predicted Performance of the MIRI Coronagraphs
Greenbaum, A.Z., Pueyo, L., Sivaramakrishnan, A., et al. 2015, ApJ, 798, 68
An Image-Plane Algorithm for JWST's Non-Redundant Aperture Mask Data
Rajan, A., et al. 2015, ApJ 809, L33
Characterizing the Atmospheres of the HR8799 Planets with HST/WFC3
Durcan, S., Janson, M., & Carson, J. 2016, ApJ, 824, 58
High Contrast Imaging with Spitzer: Constraining the Frequency of Giant Planets out to 1000 AU separations
Konopacky, Q. M., Barman, T. S., Macintosh, B. A., and Marois, C. 2013, "Detection of carbon monoxide and water absorption lines in an exoplanet atmosphere," Science, published online 14 MAR 2013