Star formation in the Perseus complex : a tale of seven clusters
Abstract
Following the recent advances in astrometry of Gaia DR2, I use its photometric and kinematic
data to explore the structure of the star forming region associated with the molecular cloud
of Perseus. Apart from the two well-known clusters, IC 348 and NGC 1333, I present five new
clusters, which contain between 30 and 300 members, named Autochthe, Alcaeus, Mestor,
Electryon and Heleus. I construct reliable membership lists for the seven clusters and of the
dispersed population of the complex.
I investigate the youth of individual sources within the clusters, and outside, using a combination
of youth indicators from Gaia, WISE, Spitzer, and Planck data. These give the relative ages of the clusters and yield lists of young sources (τ[sub](age) ≲ 5 Myr). Based on this
work, IC 348 spans ages from 1 Myr up to 5 Myr. Autochthe and NGC 1333 are the youngest
clusters at 1 Myr. These three clusters constitute the star-forming centers of the cloud. Heleus
and Mestor have average ages of about 4 Myr while Alcaeus and Electryon are at about 5 Myr.
NGC 1333, Autochthe and IC 348 have the highest disc fractions (66±14%, 58±30% and 41±7%) while the rest four clusters have fractions below ∼30%.
Finally I construct the system Mass Function (MF) for all seven clusters by determining
the masses of the cluster members using 2MASS photometry. For 0.08 < m/M[sub]☉︎ < 1.4 the MF slopes are in agreement for the seven clusters and range between 0.5 and 1.3. These are by
and large smaller than the Kroupa (2001) slope of 1.3.
The region of Perseus exhibits a bimodal nature in proper motion, spatial distribution, and
age span. This bimodality is supported by a star-formation scenario where the seven clusters
have formed from two kinematically distinct sub-clouds.
Type
Thesis, PhD Doctor of Philosophy
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