A new mechanical stellar wind feedback model for the Rosette Nebula

Abstract

The famous Rosette Nebula has an evacuated central cavity formed from the stellar winds ejected from the 2-6 Myr old codistant and comoving central star cluster NGC 2244. However, with upper age estimates of less than 110 000 yr, the central cavity is too young compared to NGC 2244 and existing models do not reproduce its properties. A new proper motion study herein using Gaia data reveals the ejection of the most massive star in the Rosette, HD 46223, from NGC 2244 occurred 1.73 (+0.34, −0.25) Myr (1σ uncertainty) in the past. Assuming this ejection was at the birth of the most massive stars in NGC 2244, including the dominant centrally positioned HD 46150, the age is set for the famous ionized region at more than 10 times that derived for the cavity. Here, we are able to reproduce the structure of the Rosette Nebula, through simulation of mechanical stellar feedback from a 40 M star in a thin sheet-like molecular cloud. We form the 135 000 M cloud from thermally unstable diffuse interstellar medium (ISM) under the influence of a realistic background magnetic field with thermal/magnetic pressure equilibrium. Properties derived from a snapshot of the simulation at 1.5 Myr, including cavity size, stellar age, magnetic field, and resulting inclination to the line of sight, match those derived from observations. An elegant explanation is thus provided for the stark contrast in age estimates based on realistic diffuse ISM properties, molecular cloud formation and stellar wind feedback.

Disruption of the Orion molecular core 1 by wind from the massive star θ1 Orionis C

“…Stellar winds from O-type massive stars are very effective in disrupting molecular cores and star formation and, as stellar wind energy input is dominated by the most massive stars in a cluster while SN energy input is dominated by the more numerous B-type stars, this has a direct impact on cosmological simulations. As our study shows, relevant stellar feedback processes act on much smaller scales (0.2–2pc) than hydrodynamic studies of ISM evolution (>2pc) or cosmological simulations (>50 pc) resolve2,4,5,6,7. [CII] 1.9 THz studies on the dynamic interaction of massive stars through stellar winds with nearby molecular clouds can provide key validation for theoretical studies.…”

“…Mechanical and radiative energy input by massive stars stir up the environment, heat the gas, produce cloud & intercloud phases in the interstellar medium and disrupt molecular clouds, the birthsites of new stars1,2. Ionization by UV photons, stellar wind action and supernova explosions control molecular clouds lifetimes3,4,5,6,7. Theoretical studies predict that momentum injection by radiation dominates by far over momentum injected by a stellar wind8, but this has hitherto been difficult to assess observationally.…”

Expanding bubbles in Orion A: [C II] observations of M 42, M 43, and NGC 1977

“…However, there is evidence that also stellar winds have a profound impact on the interstellar medium (ISM). Observations and models have long attested to the importance of stellar winds from massive stars as sources of mechanical energy that can have profound influence on the direct environment (Castor et al 1975;Weaver et al 1977;Wareing et al 2018;Pabst et al 2019). These stellar winds drive a strong shock into its surroundings, which sweeps up ambient gas into dense shells.…”

Molecular tracers of radiative feedback in Orion (OMC-1)

“…A strong FUV radiation field1 ( G 0 >10 3 ) induces a plethora of dynamical effects (e.g., Hill & Hollenbach 1978; Hosokawa & Inutsuka 2006; Wareing et al 2018; Bron et al 2018) and chemical changes in the cloud (e.g., Hogerheijde et al 1995; Cuadrado et al 2015, 2016, 2017; Nagy et al 2017; Goicoechea et al 2017). This stellar feedback is not limited to the close vicinity of massive stars, but it can determine the gas physical conditions at scales of several parsec (e.g., Stacey et al 1993; Herrmann et al 1997; Goicoechea et al 2015b) and drive the evolution of the natal cloud itself.…”