The late-stage evolution of very massive stars such as \eta Carinae may be dominated by episodic mass ejections which may later lead to Type II superluminous supernova ( SLSN-II ; e.g. , SN 2006gy ) .
However , as long as \eta Car is one of a kind , it is nearly impossible to quantitatively evaluate these possibilities .
Here we announce the discovery of five objects in the nearby ( \sim 4 - 8 Mpc ) massive star-forming galaxies M 51 , M 83 , M 101 and NGC 6946 that have optical through mid-IR photometric properties consistent with the hitherto unique \eta Car .
The Spitzer mid-IR spectral energy distributions of these L _ { bol } \simeq 3 - 8 \times 10 ^ { 6 } L _ { \odot } objects rise steeply in the 3.6 - 8 \micron bands , then turn over between 8 and 24 \micron , indicating the presence of warm ( \sim 400 - 600 K ) circumstellar dust .
Their optical counterparts in HST images are \sim 1.5 - 2 dex fainter than their mid-IR peaks and require the presence of \sim 5 - 10 M _ { \odot } of obscuring material .
Our finding implies that the rate of \eta Car-like events is a fraction f = 0.094 ( 0.040 < f < 0.21 at 90 % confidence ) of the core-collapse supernova ( ccSN ) rate .
If there is only one eruption mechanism and SLSN-II are due to ccSN occurring inside these dense shells , then the ejection mechanism is likely associated with the onset of carbon burning ( \sim 10 ^ { 3 } -10 ^ { 4 } years ) which is also consistent with the apparent ages of massive Galactic shells .