James Webb Space Telescope Feed Post

A JWST survey of the Trapezium Cluster & inner Orion Nebula. I. Observations & overview

A selection of other dark features seen in the F115W mosaic. The central coordinate for each image is shown along with a scale bar in arcseconds and au, the latter assuming a distance of 390 pc to Orion. N is up and E left in each panel. The intensity is displayed logarithmically and the contrast has been enhanced to allow close examination of the features, but typically the dark regions are 10–20% fainter than the surrounding nebula. Diffraction spikes from nearby bright stars are seen crossing two of the images. (a) A concentrated dark shadow around a faint source, similar in appearance to a silhouette disk but only seen in F115W. Its coordinate-based name is 183–400; the well-known true silhouette disk 183–405 is seen in the same picture. (b) The “Stupa”; the central star is LRY251 (Luhman et al. 2000). (c) The “Bat”; the central star is LRY200 (Luhman et al. 2000). (d) An isolated dark stain without any associated point sources. Abstract: We present a near-IR survey of the Trapezium Cluster and inner Orion Nebula using the NASA/ESA/CSA James Webb Space Telescope. The survey with the NIRCam instrument covers 10.9 x 7.5 arcminutes (~1.25 x 0.85 pc) in twelve wide-, medium-, and narrow-band filters from 1-5 microns and is diffraction-limited at all wavelengths, providing a maximum spatial resolution of 0.063 arcsec at 2 microns, corresponding to ~25 au at Orion. The suite of filters chosen was designed to address a number of scientific questions including the form of the extreme low-mass end of the IMF into the planetary-mass range to 1 Jupiter mass and below; the nature of ionised and non-ionised circumstellar disks and associated proplyds in the near-IR with a similar resolution to prior HST studies; to examine the large fragmented outflow from the embedded BN-KL region at very high resolution and fidelity; and to search for new jets and outflows from young stars in the Trapezium Cluster and the Orion Molecular Cloud 1 behind. In this paper, we present a description of the design of the observational programme, explaining the rationale for the filter set chosen and the telescope and detector modes used to make the survey; the reduction of the data using the JWST pipeline and other tools; the creation of large colour mosaics covering the region; and an overview of the discoveries made in the colour images and in the individual filter mosaics. Highlights include the discovery of large numbers of free-floating planetary-mass candidates as low as 0.6 Jupiter masses, a significant fraction of which are in wide binaries; new emission phenomena associated with the explosive outflow from the BN-KL region; and a mysterious "dark absorber" associated with a number of disparate features in the region, but which is seen exclusively in the F115W filter. Further papers will examine those discoveries and others in more detail.