English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present narrowband WFC3-UVIS and -IR images of four externally irradiatedprotostellar jets in the Carina nebula: HH666, HH901, HH902, and HH1066. Thesemassive jets are unusual because they are bathed in UV radiation from dozens ofnearby O stars, but despite the strong incident ionizing radiation, portions ofthe jet remain neutral. Near-IR [Fe II] images reveal dense, neutral gas thatwas not seen in previous studies of H-alpha emission. We show that near-IR [FeII] emitting gas must be self-shielded from Lyman continuum photons, regardlessof its excitation mechanism (shocks, FUV radiation, or both). High densitiesare required for the survival of Fe+ amid the strong Lyman continuum from Tr14,raising estimates of the mass-loss rates by an order of magnitude. Higher jetmass-loss rates require higher accretion rates onto their driving protostars,implying that these jets are driven by intermediate-mass (IM; ~2-8 Msun) stars.Indeed, the IR driving sources of two of these outflows have luminosities thatrequire IM protostars. All four of these HH jets are highly collimated, withopening angles of only a few degrees, similar to those observed in low-massprotostars. We propose that these jets reflect essentially the same outflowphenomenon seen in wide-angle molecular outflows associated with IM andhigh-mass protostars, but that the collimated atomic jet core is irradiated andrendered observable in Carina's harsh radiative environment. In more quiescentenvironments, this atomic core remains invisible, and outflows traced byshock-excited molecules in the outflow cavity give the impression that theseoutflows have a wider opening angle. Thus, the externally irradiated jets inCarina constitute a new view of collimated jets from IM protostars, and offerstrong additional evidence that stars up to at least ~8 Msun form by the sameaccretion mechanisms as low-mass stars.

HST/WFC3 Imaging of Protostellar Jets in Carina: [Fe II] Emission Tracing Massive Jets from Intermediate Mass Protostars