HST and UKIRT Observations of the Center of the Trifid Nebula: Evidence for the Photoevaporation of a Proplyd and a Protostellar Condensation

Abstract

The Trifid nebula (M20) is a well-known prominent optical HII region trisected by bands of obscuring dust lanes and excited by an O7.5 star HD 164492A. Previous near-IR, mid-IR and radio continuum observations of the cluster of stars at the center of the Trifid nebula indicated circumstellar disks associated with hot stars with envelopes that are photoionized externally by the UV radiation from the hot central star, HD 164492A. Using WFPC2 of the HST, we present evidence of a resolved proplyd in H$\alpha$ and [SII] line emission from a stellar source emitting cool dust emission. Using UKIRT, an infrared observation of the stellar source with a proplyd indicates a late F -- mid G spectral type. We also note a remarkable complex of filamentary and sheet-like structures which appear to arise from the edge of a protostellar condensation. These observations are consistent with a picture in which the bright massive star HD 164492A is responsible for the photoevaporation of protoplanetary disks of other less-massive members of the cluster as well as the closest protostellar condensation facing the central cluster. Using the evidence for a proplyd, we argue that the massive and intermediate mass members of the cluster, HD 164492C (B6 star) and HD 164492 (Herbig Be star) have disks associated with them.

13 pages, 5 figures, AJ, in press

References in corpus (2)

• The Photoionization of a Star-Forming Core in the Trifid Nebula
• Proper Motion of the Irradiated Jet HH 399 in the Trifid Nebula

Cited by in corpus (14)

• Molecular clouds in the Trifid nebula M20; Possible evidence for a cloud-cloud collision in triggering the formation of the first generation stars
• Triggered O star formation in M20 via cloud-cloud collision: Comparisons between high-resolution CO observations and simulations
• Radio Continuum Observations of the Galactic Center: Photoevaporative Proplyd-like Objects near Sgr A*
• Disk Dispersal: Theoretical Understanding and Observational Constraints
• Cloud fragmentation and proplyd-like features in HII regions imaged by HST
• Ionized gas diagnostics from protoplanetary discs in the Orion Nebula and the abundance discrepancy problem
• Star Formation in the Trifid Nebula
• HD 164492C: a rapidly-rotating, H$\alpha$-bright, magnetic early B star associated with a 12.5d spectroscopic binary
• Accretion and outflow in the proplyd-like objects near Cygnus OB2
• B fields in OB stars (BOB): The magnetic triple stellar system HD 164492C in the Trifid nebula
• Probing X-ray photoevaporative winds through their interaction with ionising radiation in cluster environments: the case for X-ray proplyds
• The Young Stellar Population, Distance, and Cloud-Cloud Collision Induced Star Formation Scenario of the Trifid Nebula
• SDSS-V LVM: Resolving Physical Conditions in the Trifid Nebula
• On the nature of V2282 Sgr