Did Carinae's Weigelt Blobs Originate circa 1941?

Abstract

We report astrometric measurements of {η} Carinae's Weigelt blobs Cand D (also known as speckle objects C and D) derived from observationswith the Hubble Space Telescope Wide Field Planetary Camera 2. Usingthree epochs of data with a temporal baseline of 5.9 yr, we measure blobD's proper motion relative to the central star to be 4.4+/-1.4 masyr^{-1}, implying a date of origin of1934.1^{+16.0}_{-31.7}. Similarly, using two epochs witha 1.7 yr baseline, we measure blob C's relative proper motion to be3.8+/-5.6 mas yr^{-1}, indicating a probability of ejectionafter 1910 of ~60% we view this as confirming the more accurate blob Dresults (assuming coevality), with a combined post-1910 ejectionindicated at a ~90% confidence level. The blob D date roughly coincideswith the sudden brightening of the central star observed in 1941 andprovides a possible explanation for the onset of certain narrow spectralfeatures, associated with the Weigelt blobs, that have been observedonly since the mid-1940s. We propose that the ejection of Weigelt blobsC and D was related to this 1941 event.