James Webb Space Telescope Feed Post

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

Subsections of the SW composite (Figure 3), the LW composite (Figure 4), and F187N image focussing on the Trapezium stars and the region to the immediate south where a number of well-known proplyds are located. Some of these are indicated in the F187N image using a mix of the nomenclatures established by (Laques & Vidal 1979; O’Dell et al. 1993; Bally et al. 2000; Ricci et al. 2008), along with some Herbig-Haro objects and the names of the Trapezium stars. The global and local intensity and contrast have been adjusted with respect to the main composites to make key features clearer. The images are centred just N of ? 1 Ori C at 05h 35m 16.46s, -05? 23’ 21.8” (J2000.0), are oriented close to N up, E left, and each spans 67.1 × 41.8 arcsec or 0.127 × 0.079 pc assuming a distance of 390 pc. 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.