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

In recent years, dramatic outbursts have been identified toward massiveprotostars via infrared and millimeter dust continuum and molecular maseremission. The longest lived outburst ($>6$ yr) persists in NGC6334I-MM1, adeeply-embedded object with no near-IR counterpart. Using FORCAST and HAWC+ onSOFIA, we have obtained the first mid-infrared images of this field since theoutburst began. Despite being undetected in pre-outburst ground-based 18 $\mu$mimages, MM1 is now the brightest region at all three wavelengths (25, 37, and53 $\mu$m), exceeding the ultracompact HII region MM3 (NGC6334F). Combining theSOFIA data with ALMA imaging at four wavelengths, we construct a spectralenergy distribution of the combination of MM1 and the nearby hot core MM2. Thebest-fit Robitaille radiative transfer model yields a luminosity of$(4.9\pm0.8)\times10^4 L_\odot$. Accounting for an estimated pre-outburstluminosity ratio MM1:MM2 = $2.1\pm0.4$, the luminosity of MM1 has increased bya factor of $16.3\pm4.4$. The pre-outburst luminosity implies a protostar ofmass 6.7 $M_\odot$, which can produce the ionizing photon rate required topower the pre-outburst hypercompact HII region surrounding the likelyoutbursting protostar MM1B. The total energy and duration of the outburstexceed the S255IR-NIRS3 outburst by a factor of $\gtrsim3$, suggesting adifferent scale of event involving expansion of the protostellar photosphere(to $\gtrsim$ 20 $R_\odot$), thereby supporting a higher accretion rate($\gtrsim$0.0023 $M_\odot$ yr$^{-1}$) and reducing the ionizing photon rate. Inthe grid of hydrodynamic models of Meyer et al. 2021, the combination ofoutburst luminosity and magnitude (3) places the NGC6334I-MM1 event in theregion of moderate total accretion ($\sim$0.1-0.3 $M_\odot$) and hence longduration ($\sim$40-130 yr).

The Extraordinary Outburst in the Massive Protostellar System NGC6334I-MM1: Strong Increase in Mid-Infrared Continuum Emission