A WISE Census of Young Stellar Objects in Perseus OB2 Association

TL;DR

This study uses WISE infrared data to identify and analyze young stellar objects in the Perseus OB2 region, revealing their distribution, characteristics, and evolutionary stages with improved selection methods.

Contribution

It introduces a novel SED fitting approach for YSO identification, reducing contamination and detecting transitional disks better than traditional color-color methods.

Findings

Identified 275 YSO candidates with spatial distribution indicating ongoing star formation.

Discovered three distinct age groups among YSOs, consistent with the region's star formation history.

Compared SED fitting with color selection, showing improved detection of evolved and transitional disks.

Abstract

We have performed a WISE (Wide-Field Infrared Survey Explorer) based study to identify and characterize young stellar objects (YSOs) in 12x12 degree Perseus OB2 association. Spectral energy distribution (SED) slope in range of 3.4-12 micron and a 5sigma selection criteria were used to select our initial sample. Further manual inspection reduced our final catalog to 156 known and 119 YSO candidate. The spatial distribution of newly found YSOs all over the field shows an older generation of star formation which most of its massive members have evolved into main sequence stars. In contrast, the majority of younger members lie within the Perseus molecular cloud and currently active star forming clusters such as NGC1333 and IC348. We also identified additional 66 point sources which passed YSO selection criteria but are likely AGB stars. However their spatial distribution suggests that they may contain a fraction of the YSOs. Comparing our results with the commonly used color-color selections, we found that while color selection method fails in picking up bright but evolved weak disks, our SED fitting method can identify such sources, including transitional disks. In addition we have less contamination with background sources such as galaxies, but in a price of loosing fainter (Jmag > 12) YSOs. Finally we employed a Bayesian Monte Carlo SED fitting method to determine the characteristics of each YSO candidate. Distribution of SED slopes and model driven age and mass confirms separated YSO populations with suggested three age groups of younger than 1 Myr old, 1-5 Myr old, and older than 5 Myrs which agrees with the age of Per OB2 association and currently star forming sites within the cloud.