2009/12/19 by T. Szeifert, S. Hubrig, M. Schöller +4 · 2 citations
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.1051/0004-6361/200913704
letter to A&A, accepted 17/12/2009
arxiv created 2009/12/19 · openalex publication_date 2010/01/01 · arxiv updated 2015/05/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
Z CMa is a binary system which consists of two young stars: A Herbig AeBe component "Z CMa NW" embedded in a dust cocoon and a less massive component "Z CMa SE", which is classified as a FU Orionis type star. Recently, the system showed the largest outburst reported during the almost 90 years of available observations. During the recent outburst we detect that the Z CMa system is polarized by 2.6% in the continuum and emission line spectrum, with a position angle still perpendicular to the jet. From the high level of polarization we conclude that the outburst is associated with the dust embedded Herbig AeBe NW component. The main result of our studies is that the bolometric luminosity of Z CMa remained surprisingly constant during the recent "outburst". We conclude that either the geometry of the cavity through which the light escapes from the cocoon has opened a new path, or that the screen of dust, which reflects the light toward the observer became more efficient causing the observed increase of the visual brightness by about 2.5 magnitudes.