The cosmic DANCe of Perseus

Abstract

Context. Star-forming regions are excellent benchmarks for testing and validating theories of star formation and stellar evolution. The Perseus star-forming region, being one of the youngest (< 10 Myr), closest (280−320 pc), and most studied in the literature, is a fundamental benchmark. Aims. We aim to study the membership, phase-space structure, mass, and energy (kinetic plus potential) distribution of the Perseus star-forming region using public catalogues (Gaia, APOGEE, 2MASS, and Pan-STARRS). Methods. We used Bayesian methodologies that account for extinction to identify the Perseus physical groups in the phase-space, retrieve their candidate members, derive their properties (age, mass, 3D positions, 3D velocities, and energy), and attempt to reconstruct their origin. Results. We identify 1052 candidate members in seven physical groups (one of them new) with ages between 3 and 10 Myr, dynamical super-virial states, and large fractions of energetically unbounded stars. Their mass distributions are broadly compatible with that of Chabrier for masses ≳0.1 M⊙ and do not show hints of over-abundance of low-mass stars in NGC 1333 with respect to IC 348. These groups’ ages, spatial structure, and kinematics are compatible with at least three generations of stars. Future work is still needed to clarify if the formation of the youngest was triggered by the oldest. Conclusions. The exquisite Gaia data complemented with public archives and mined with comprehensive Bayesian methodologies allow us to identify 31% more members than previous studies, discover a new physical group (Gorgophone: 7 Myr, 191 members, and 145 M⊙), and confirm that the spatial, kinematic, and energy distributions of these groups support the hierarchical star formation scenario.

Walkaway Star Candidates in IC 348 and Their Possible Birthplaces

“…The Perseus molecular cloud is located at the edge of the Perseus-Taurus Shell, discovered in 3D dust maps by Bialy et al (2021), with a dynamical evolution that has likely been influenced by feedback (see the review by Zucker et al 2022). In addition to IC 348 and NGC 1333, the Perseus region also contains several 5 Myr subgroups (e.g., Pavlidou et al 2021;Olivares et al 2023). The kinematic analysis of Perseus by Kounkel et al (2022a) separates the subgroups in Perseus into two clouds, which supports the hypothesis that star formation in IC 348 was triggered by a cloud-cloud collision.…”

“…Stars that differ by more than 3.2 mas yr −1 (5 km s −1 at 325 pc) from the centroid proper motion of IC 348 are identified as proper motion outliers. 10 Twelve stars in a subgroup concentrated at (6.8, −9.7) mas yr −1 in proper motion space are not considered as proper motion outliers because these stars belong to the other subgroups in the Perseus molecular cloud (Alcaeus and Gorgophone, as identified by Olivares et al 2023). For comparison, of our proper motion outliers, only LRL 170 is listed in the Olivares et al (2023) catalog, because its proper motion is near the 5 km s −1 limit to be classified as a candidate walkaway star and near their selection limit.…”

Young nearby open clusters and their luminosity functions

“…These three clusters are within b = 10 deg but have been included because they are nearby and young and have been studied in detail in the literature (e.g., Randich et al 2001;Lodieu et al 2005Lodieu et al , 2012Lodieu et al , 2019aDobbie et al 2010;Nisak et al 2022). The following clusters/regions Sigma Orionis (Garrison 1967;Barrado y Navascués et al 2001;Caballero 2018), IC 348 and NGC 1333 (Luhman et al 2016;Olivares et al 2023), Feigelson 1 (also known as Cha Cluster; Dickson-Vandervelde et al 2021), Platais 2 and 5 (Platais et al 1998), UBC 19 (Castro-Ginard et al 2018, Melotte 227 (Epstein 1968), Collinder 65 (Yen et al 2018), Collinder 70 (Caballero & Solano 2008), and ASCC 100 (Kharchenko et al 2005) were removed because they are not isolated, and many of them are found in very young complex regions (e.g., Taurus, Orion, Upper Scorpius and Rho Ophiuchi) that display an extended structure that is often non-trivial to isolate from the surrounding environment. This selection left us with 49 clusters, which are presented in a list in Table 1 with their equatorial and Galactic coordinates, distances, and numbers of initial candidates with and without radial velocities.…”