Infrared excess in semi-regular variables in the Magellanic Clouds

Martin A.T Groenewegen,Monika I Jurkovic,M Catelan,W Gieren

doi:10.1051/epjconf/201715201018

Abstract

Following up on our recent work we are investigating if Type II Cepheids could be “hiding” in the sample of stars classified by the OGLE team as long-period variables.

Highlights

In two recent papers, [1, 2] studied the 246 Type II Cepheids (T2Cs) and 89 Anomalous Cepheids (ANCEPs) discovered in the OGLE-III survey in the SMC and LMC ([5, 7, 8])
They are typically separated into 3 subgroups according to their pulsation periods: the BL Herculis (BLH) stars have periods 1 − 4 days, the W Virginis (WVir) 4 − 20 days and the RV Tauris (RVT) 20 − 70 days pulsation periods
For ∼ 60% of the RVT and ∼ 10% of the (p)W Vir objects an infrared excess is detected from the spectral energy distributions (SEDs) fitting

Summary

Introduction

In two recent papers, [1, 2] (and see these proceedings, [3]) studied the 246 Type II Cepheids (T2Cs) and 89 Anomalous Cepheids (ANCEPs) discovered in the OGLE-III survey in the SMC and LMC ([5, 7, 8]). Variables with RVT-like light curves at longer periods may well exist but would appear in the OGLE samples of the long-period variables (LPVs) ([6, 9]). In [1] the spectral energy distributions (SEDs) were constructed for all these stars, using available photometry from the literature, and fitted with a dust radiative transfer code.

Results

Conclusion