English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

In this paper we investigate the robustness of age measurements, age spreads,and stellar models in young pre-main sequence stars. For this effort, we studya young cluster, $\lambda$ Orionis, within the Orion star-forming complex. Weuse Gaia data to derive a sample of 357 targets with spectroscopic temperaturesfrom spectral types or from the automated spectroscopic pipeline in APOGEE Net.After accounting for systematic offsets between the spectral type and APOGEEtemperature systems, the derived properties of stars on both systems areconsistent. The complex ISM, with variable local extinction, motivates astar-by-star dereddening approach. We use a spectral energy distribution (SED)fitting method calibrated on open clusters for the Class III stars. For theClass II population, we use a Gaia G-RP dereddening method, minimizingsystematics from disks, accretion, and other physics associated with youth. Thecluster age is systematically different in models incorporating the structuralimpact of starspots or magnetic fields than in nonmagnetic models. Our meanages range from 2-3 Myr (nonmagnetic models) to 3.9$\pm$0.2 Myr in the SPOTSmodel (f=0.34). We find star-by-star dereddening methods distinguishing betweenpre-MS classes provide a smaller age spread than techniques using a uniformextinction, and infer a minimum age spread of 0.19 dex and a typical age spreadof 0.35 dex after modelling age distributions convolved with observed errors.This suggests that the $\lambda$ Ori cluster may have a long star formationtimescale and that spotted stellar models significantly change age estimatesfor young clusters.

Age Spreads and Systematics in {\lambda} Orionis with Gaia DR2 and the SPOTS tracks