James Webb Space Telescope Feed Post

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

A section of the SW composite located to the NNW of BN showing some of the fingers of emission expanding rapidly away from the the region around Source I in the BN-KL region (see Figure 11). The fingers are predominantly red, indicating H2 emission in the F212N filter, replaced by green and white emission near the tips of the fingers, indicating [Fe II] 1.644 µm emission in the F162M filter and a mix of emission also including ionised Pa-a in the F187N filter, respectively. Inset (a) shows a more detailed view of the tip of HH 201 with the discovery that there is also additional H2 emission wrapped around the [Fe II] emission and even extending into spikes pointing in the direction of motion of the finger. Inset (b) shows a region further down the same finger, revealing a mix of turbulent and apparently laminar flow along the sides. Herbig-Haro object names are given for some of the fingertips and the proplyd surrounding a binary system (121–132, Robberto et al. 2008) is marked. The main image is centred at 05h 35m 11.6s, -05? 20’ 54” (J2000.0) and covers 54.9 × 82.2 arcsec or 0.10 × 0.16 pc assuming a distance of 390 pc. The sub-panels are each 7.9 × 7.9 arcsec. 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.