A cluster of class I/f/II young stellar objects discovered near the Cepheid SU Cas

Abstract

Preliminary constraints are placed on a cluster of young stellar objects (J2000 02:54:31.4 +69:20:32.5) discovered in the field of the classical Cepheid SU Cas. The Wide-field Infrared Survey Explorer (WISE) 3.4-, 4.6-, 12- and 22-µm images reveal that the cluster deviates from spherical symmetry and exhibits an apparent diameter of 3 × 6 arcmin. Spectral energy distributions constructed using the Two Micron All Sky Survey (2MASS) K_s (2.2 µm) and WISE photometry indicate that 19 (36 per cent) class I, 21 (40 per cent) class f and 13 (25 per cent) class II objects lie r < 3 arcmin from the cluster centre. Conversely, 11 (18 per cent) class I, 13 (21 per cent) class f and 37 (61 per cent) class II objects were detected for r > 3 arcmin. Approximately 50 per cent of the class I sources within r < 3 arcmin were classified solely using WISE photometry owing to the absence of detections by 2MASS.