Class I/II Jets with JWST: Mass-loss Rates, Asymmetries, and Binary-induced Wigglings

We present JWST NIRSpec spectroimaging observations of jets from four edge-on protoplanetary disks that exhibit clear signatures of MHD disk winds. Bipolar jets are detected and spatially resolved in over 30 shock-excited forbidden lines, multiple Paschen and Brackett series lines of atomic hydrogen...

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Main Authors: Naman S. Bajaj, Ilaria Pascucci, Tracy L. Beck, Suzan Edwards, Sylvie Cabrit, Joan R. Najita, Kamber Schwarz, Dmitry Semenov, Colette Salyk, Uma Gorti, Sean D. Brittain, Sebastiaan Krijt, Maxime Ruaud, James Muzerolle Page
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astronomical Journal
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Online Access:https://doi.org/10.3847/1538-3881/adc73c
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Summary:We present JWST NIRSpec spectroimaging observations of jets from four edge-on protoplanetary disks that exhibit clear signatures of MHD disk winds. Bipolar jets are detected and spatially resolved in over 30 shock-excited forbidden lines, multiple Paschen and Brackett series lines of atomic hydrogen, and the high-energy excitation line of atomic helium (1.083 μ m). This helium line is the brightest jet tracer toward HH 30 and FS TauB, which also exhibit asymmetric intensity between their red- and blueshifted lobes in all tracers, including the [Fe ii ] and He i lines. Extinction maps reveal no significant differences across the lobes, suggesting an asymmetric jet-launching mechanism rather than environmental effects. Diagnostic line ratios yield consistent shock speeds of 50–60 km s ^−1 , jet ionization fractions of 0.1–0.2, and pre-shock electron densities of 1000 cm ^−3 . Combined with pixel-by-pixel electron density maps and [Fe ii ] line luminosities, we estimate jet mass-loss rates using three independent methods, averaging around a few 10 ^−9 M _⊙ yr ^−1 . We estimate the accretion rates for these sources as 10× the jet mass-loss rates and find them to match well with the independently derived accretion estimates of other Class II sources in the Taurus star-forming region. Owing to JWST’s high precision, we also investigate jet wiggling and find Tau 042021 to showcase the perfect case of mirror-symmetric wiggling, which can only be explained by the motion of the jet source around a stellar companion. Modeling this wiggling suggests Tau 042021 to host a 0.33 and 0.07 M _⊙ binary at the center with a binary separation of 1.35 au and an orbital period of 2.5 yr.
ISSN:1538-3881