SPYGLASS. IV. New Stellar Survey of Recent Star Formation within 1 kpc

Abstract

Young stellar populations provide a powerful record that traces millions of years of star formation history in the solar neighborhood. Using a revised form of the SPYGLASS young star identification methodology, we produce an expanded census of nearby young stars (age < 50 Myr). We then use the HDBSCAN clustering algorithm to produce a new SPYGLASS Catalog of Young Associations, which reveals 116 young associations within 1 kpc. More than 25% of these groups are largely new discoveries, as 20 are substantively different from any previous definition, and 10 have no equivalent in the literature. The new associations reveal a yet undiscovered demographic of small associations with little connection to larger structures. Some of the groups we identify are especially unique for their high transverse velocities, which can differ from the solar velocity by 30–50 km s−1, and for their positions, which can reach up to 300 pc above the galactic plane. These features may suggest a unique origin, matching existing evidence of infalling gas parcels interacting with the disk interstellar medium. Our clustering also suggests links between often-separated populations, hinting to direct structural connections between Orion Complex and Perseus OB2, and between the subregions of Vela. The ∼30 Myr old Cepheus-Hercules association is another emerging large-scale structure, with a size and population comparable to Sco-Cen. Cep-Her and other similarly aged structures are also found clustered along extended structures perpendicular to known spiral arm structure, suggesting that arm-aligned star formation patterns have only recently become dominant in the solar neighborhood.

High-resolution Pan-STARRS and SMA Observations of IRAS 23077+6707: A Giant Edge-on Protoplanetary Disk

“…In summary, we find it highly plausible that the total extent of the disk's (sub)millimeter emission is likely tracing dust and gas out to radii of at least ∼7″, far larger than any other reported protoplanetary disks. At the distance to the Cepheus star-forming region (spanning a range of 180-800 pc; see, e.g., Kun et al 2008Kun et al , 2009Szilágyi et al 2021;Kerr et al 2023) to which IRAS 23077+6707 is likely associated, such large radii would suggest that IRAS 23077+6707ʼs disk thus spans 1000 s of astronomical units in size.…”

A Quick Guide to Nearby Young Associations

“…The advent of the Hipparcos mission allowed to begin uncovering such "moving groups" of stars in the immediate neighborhood of the Sun (e.g., see Kastner et al 1997;Zuckerman & Webb 2000;Zuckerman et al 2001Torres et al 2008 for relevant reviews on the topic), but it is only with the Gaia mission (Gaia Collaboration et al 2016) that it became possible possible to catalog loose associations at distances much beyond 100 pc (e.g., see Oh et al 2017;Kounkel & Covey 2019;Tang et al 2019;Meingast et al 2021) or with particularly low densities and intermediate ages in the immediate solar neighborhood (Moranta et al 2022;Gagné et al 2023). The rich data provided by Gaia also made it possible to unveil the full complexity of the velocity distribution and sub-populations in young OB associations as well as younger star-forming regions (see e.g., Kerr et al 2021;Liu et al 2021;Kerr et al 2022aKerr et al , 2022bKerr et al , 2023.…”