IRAM and Gaia views of multi-episodic star formation in IC1396A: The origin and dynamics of the Class 0 protostar at the edge of an HII region

Abstract

(Abridged) IC1396A is a cometary globule containing the Class 0 source IC1396A-PACS-1. We use IRAM 30m and Gaia DR2 data to explore the star-formation history of IC1396A and investigate the possibilities of triggered star formation. IRAM and Herschel continuum data reveal dust temperatures and column densities. Heterodyne data reveal the velocity structure of the gas. Gaia DR2 proper motions for the stars complete the kinematics of the region. IC1396A-PACS-1 shows molecular emission similar to a hot corino with warm carbon chain chemistry, and is surrounded by gas at velocities significantly different from the velocities of the Tr37 cluster. Combining the velocity, column density, and temperature information and Gaia DR2 kinematics, we confirm that IC1396A has suffered various episodes of star formation. IC1396A-PACS-1 is probably the last intermediate-mass protostar that will form within IC1396A, showing evidence of triggering by radiative driven implosion. Chemical signatures place IC1396A-PACS-1 among the youngest protostars known. Gaia DR2 data reveal velocities in the plane of the sky $\sim$4km/s for IC1396A with respect to Tr37. The total velocity difference (8 km/s) between the Tr37 cluster and IC1396A is too small for IC1396A to have undergone substantial rocket acceleration, which imposes constraints on the distance to the ionizing source in time and the possibilities of triggered star formation. The three stellar populations in the globule reveal that objects located within relatively close distances ($<$0.5pc) can be formed in various episodes within a $\sim$1-2 Myr period. We expect substantial differences in initial conditions for the resulting objects and their protoplanetary disks, which may affect their evolution. Finally, evidence for short-range feedback from the embedded protostars and, in particular, the A-type star V390 Cep is also observed.

A\&A in press, 20 pages plus appendix

References in corpus (17)

• The Gaia mission
• The relation between gas and dust in the Taurus Molecular Cloud
• High-Resolution Spectroscopy in Tr37: Gas Accretion Evolution in Evolved Dusty Disks
• The Spatial Structure of Young Stellar Clusters. I. Subclusters
• Estimating distances from parallaxes. II. Performance of Bayesian distance estimators on a Gaia-like catalogue
• Estimating distances from parallaxes. III. Distances of two million stars in the Gaia DR1 catalogue
• NIKA: A millimeter-wave kinetic inductance camera
• Age Gradients in the Stellar Populations of Massive Star Forming Regions Based on a New Stellar Chronometer
• Triggered star formation in Bright-Rimmed Clouds: The Eagle Nebula revisited
• High abundance ratio of ${}^{13}$CO to C${}^{18}$O toward photon-dominated regions in the Orion-A giant molecular cloud
• HCN and HNC mapping of the protostellar core Cha-MMS1
• Complex organic molecules during low-mass star formation: Pilot survey results
• The Rapid Outbursting Star GM Cep: An EX-or in Tr 37?
• The 2014-2017 outburst of the young star ASASSN-13db: A time-resolved picture of a very low-mass star between EXors and FUors
• The Herschel/PACS view of the Cep OB2 region: Global protoplanetary disk evolution and clumpy star formation
• Evolution of Prolate Molecular Clouds at Hii Boundaries: II. Formation of BRCs of asymmetrical morphology
• Evolution of Prolate Molecular Clouds at HII Boundaries: I. Formation of fragment-core structures

Cited by in corpus (8)

• The connection between warm carbon chain chemistry and interstellar irradiation of star-forming cores
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -XIII. Ongoing triggered star formation within clump-fed scenario found in the massive ($\sim 1500$ ${\mathrm{M}}_{\odot }$) clump
• Membership analysis and 3D kinematics of the star-forming complex around Trumpler 37 using Gaia-DR3
• Star formation in IC1396: Kinematics and subcluster structure revealed by Gaia
• Search for Brown Dwarfs in IC 1396 with Subaru HSC: Interpreting the Impact of Environmental Factors on Sub-stellar Population
• What's Behind the Elephant's Trunk? Identifying Young Stellar Objects on the Outskirts of IC1396
• Near-Infrared Variability of Low Mass Stars in IC 1396A and TR 37
• Investigation of Rocket Effect in Bright-Rimmed Clouds using Gaia EDR3