What's Behind the Elephant's Trunk? Identifying Young Stellar Objects on the Outskirts of IC1396

Abstract

Empirically, the estimated lifetime of a typical protoplanetary disk is $<5-10$ Myr. However, the disk lifetimes required to produce a variety of observed exoplanetary systems may exceed this timescale. Some hypothesize that this inconsistency is due to estimating disk fractions at the cores of clusters, where radiation fields external to a star-disk system can photoevaporate the disk. To test this, we have observed a field on the western outskirts of the IC 1396 star-forming region with \textit{XMM-Newton} to identify new Class III YSO cluster members. Our X-ray sample is complete for YSOs down to $1.8M_{\odot }$. We use a subset of these X-ray sources that have near- and mid-infrared counterparts to determine the disk fraction for this field. We find that the fraction of X-ray-detected cluster members that host disks in the field we observe is $17_{-7}^{+10}\%$ (1$\sigma$), comparable with the $29_{-3}^{+4}\%$ found in an adjacent field centered on the cometary globule IC 1396A. We re-evaluate YSO identifications in the IC 1396A field using \textit{Gaia} parallaxes compared to previous color-cut-only identifications, finding that incorporating independent distance measurements provides key additional constraints. Given the existence of at least one massive star producing an external radiation field in the cluster core, the lack of statistically significant difference in disk fraction in each observed field suggests that disk lifetimes remain consistent as a function of distance from the cluster core.

19 pages, six figures. Published in Astronomical Journal

References in corpus (18)

• Array Programming with NumPy
• The NumPy array: a structure for efficient numerical computation
• The Gaia mission
• astroquery: An Astronomical Web-Querying Package in Python
• The WFCAM Science Archive
• High-Resolution Spectroscopy in Tr37: Gas Accretion Evolution in Evolved Dusty Disks
• X-ray Emission from T Tauri Stars and the Role of Accretion: Inferences from the XMM-Newton Extended Survey of the Taurus Molecular Cloud
• Searching the Entirety of Kepler Data. II. Occurrence Rate Estimates for FGK Stars
• X-ray Study of Triggered Star Formation and Protostars in IC 1396N
• A modular set of synthetic spectral energy distributions for young stellar objects
• Short dissipation times of proto-planetary discs - an artifact of selection effects?
• Core-Halo Age Gradients and Star Formation in the Orion Nebula and NGC~2024 Young Stellar Clusters
• An Improved Age-Activity Relationship for Cool Stars older than a Gigayear
• X-ray and IR Point Source Identification and Characteristics in the Embedded, Massive Star-Forming Region RCW 108
• Disk Detective: Discovery of New Circumstellar Disk Candidates through Citizen Science
• Star Forming Regions in Cepheus
• 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
• Near-Infrared Variability of Low Mass Stars in IC 1396A and TR 37

Cited by in corpus (1)

• Membership analysis and 3D kinematics of the star-forming complex around Trumpler 37 using Gaia-DR3