TY - JOUR
T1 - IRAM and Gaia views of multi-episodic star formation in IC1396A
T2 - The origin and dynamics of the Class 0 protostar at the edge of an HII region
AU - Sicilia Aguilar, Aurora
AU - Patel, Nimesh
AU - Fang, Min
AU - Roccatagliata, Veronica
AU - Getman, Konstantin
AU - Goldsmith, Paul
N1 - Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. V.R. is partly supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 664931. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France. This research was carried out in part at the Jet Propulsion Laboratory, which is operated for NASA by the California Institute of Technology. This research includes analysis carried out with the CASSIS software and the JPL (http://spec.jpl.nasa.gov/) spectroscopic database. CASSIS has been developed by IRAP-UPS/CNRS (http://cassis.irap.omp.eu). This work makes use of the NIST Diatomic Spectral database (https://www.nist.gov/pml/diatomicspectral-database).This work is partly based on observations obtained with the Herschel Space Telescope within open time proposal “Disk dispersal in Cep OB2”, OT1_asicilia_1. Herschel is an ESA space observatory with science in- struments provided by European-led PI consortia and with important participation from NASA.
PY - 2019/2/7
Y1 - 2019/2/7
N2 - Context. IC 1396A is a cometary globule that contains the Class 0 source IC 1396A-PACS-1, which was discovered with Herschel. Aims. We use IRAM 30m telescope and Gaia DR2 data to explore the star formation history of IC 1396A and investigate the possibilities of triggered star formation. Methods. IRAM and Herschel continuum data were used to obtain dust temperature and column density maps. Heterodyne data reveal the velocity structure of the gas. Gaia DR2 proper motions for the stars complete the kinematics of the region. Results. IC 1396A-PACS-1 presents molecular emission similar to a hot corino with warm carbon chain chemistry due to the UV irradiation. The source is embedded in a dense clump surrounded by gas at velocities that are significantly different from the velocities of the Tr 37 cluster. CN emission reveals photoevaporation, while continuum data and high-density tracers (C
18 O, HCO
+ , DCO
+ , and N
2 D
+ ) reveal distinct gaseous structures with a range of densities and masses. Conclusions. By combining the velocity, column density, and temperature information and Gaia DR2 kinematics, we confirm that the globule has experienced various episodes of star formation. IC 1396A-PACS-1 is probably the last intermediate-mass protostar that will form within IC 1396A; it shows evidence of being triggered by radiation-driven implosion. Chemical signatures such as CCS place IC 1396A-PACS-1 among the youngest known protostars. Gaia DR2 data reveal velocities in the plane of the sky ∼4 km s
-1 for IC 1396A with respect to Tr 37. The total velocity difference (8 km s
-1 ) between the Tr 37 cluster and IC 1396A is too small for IC 1396A 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 (<0.5 pc) can be formed in various star-forming episodes within ∼1-2 Myr. Once the remaining cloud disperses, we expect substantial differences in evolutionary stage and 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.
AB - Context. IC 1396A is a cometary globule that contains the Class 0 source IC 1396A-PACS-1, which was discovered with Herschel. Aims. We use IRAM 30m telescope and Gaia DR2 data to explore the star formation history of IC 1396A and investigate the possibilities of triggered star formation. Methods. IRAM and Herschel continuum data were used to obtain dust temperature and column density maps. Heterodyne data reveal the velocity structure of the gas. Gaia DR2 proper motions for the stars complete the kinematics of the region. Results. IC 1396A-PACS-1 presents molecular emission similar to a hot corino with warm carbon chain chemistry due to the UV irradiation. The source is embedded in a dense clump surrounded by gas at velocities that are significantly different from the velocities of the Tr 37 cluster. CN emission reveals photoevaporation, while continuum data and high-density tracers (C
18 O, HCO
+ , DCO
+ , and N
2 D
+ ) reveal distinct gaseous structures with a range of densities and masses. Conclusions. By combining the velocity, column density, and temperature information and Gaia DR2 kinematics, we confirm that the globule has experienced various episodes of star formation. IC 1396A-PACS-1 is probably the last intermediate-mass protostar that will form within IC 1396A; it shows evidence of being triggered by radiation-driven implosion. Chemical signatures such as CCS place IC 1396A-PACS-1 among the youngest known protostars. Gaia DR2 data reveal velocities in the plane of the sky ∼4 km s
-1 for IC 1396A with respect to Tr 37. The total velocity difference (8 km s
-1 ) between the Tr 37 cluster and IC 1396A is too small for IC 1396A 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 (<0.5 pc) can be formed in various star-forming episodes within ∼1-2 Myr. Once the remaining cloud disperses, we expect substantial differences in evolutionary stage and 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.
KW - Molecular data
KW - Open clusters and associations: individual: Tr37
KW - Photon-dominated region
KW - Stars: individual: HD 206267
KW - Stars: individual: IC 1396A-PACS-1
KW - Stars: protostars
UR - https://arxiv.org/abs/1812.07282
UR - http://www.scopus.com/inward/record.url?scp=85061368736&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201833207
DO - 10.1051/0004-6361/201833207
M3 - Article
SN - 0004-6361
VL - 622
SP - 1
EP - 27
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
M1 - A118
ER -