Almost two centuries after Eta Carinae eruption scientists found twin stars located in distant galaxies and imaged with the help of NASA/ESA Hubble Space Telescope.
The Eta Carinae eruption is an iconic and fascinating cosmic event. Since 1838 until 1845 the binary system of Eta Carinae was observed to increasingly brighten. Then, a massive explosion whirled anywhere between ten and forty times solar masses in space. The effects of the mid-19th century Eta Carinae eruption are still shrouding the Homunculus Nebula, a beautifully imaged shell of gas and dust. While fascinating, the eruption of the binary system is still very little understood. Almost two centuries after Eta Carinae eruption scientists found twin stars. These could help shed light on the mysterious cosmic event that left one of the most beautiful shrouds in our galaxy, lying only 10,000 light-years away.
Eta Carinae is located in the Carina constellation. The bright binary system is 5 million times brighter than the Sun. The two massive stars forming the binary system are caught in a 5.5-year orbit. The largest of the two stars is estimated to be 90 solar masses, while the smaller of the two stars may be a bit over 30 solar masses.
To better understand what happened during the mid-19th century eruption, the twin stars recently discovered by the scientists may offer clues on the evolution of massive stars and such cosmic events.
Massive stars like Eta Carinae are a fairly rare event. George Sonneborn and Rubab Khan with NASA’s Goddard Space Flight Center in collaboration with Scott Adams and Christopher Kochanek with the Ohio State University looked sufficiently hard to find some other examples. Thus, the twin stars were unravelled.
A first dive into Hubble Space Telescope and the Spitzer Telescope archives revealed five matches to the Eta Carinae binary system, all in distant galaxies. The twin binary systems were revealed due to both infrared and optical imaging. Typically, dust clouds are dimming the light of massive stars. The energy captured is radiated as heat. Thus, Spitzer and Hubble both played a crucial role in finding the distant twin binary systems.
The candidate twin stars to Eta Carinae are located in the NGC 6946 galaxy, the M101 galaxy and M51 galaxies. These are located in between 18 million light years away and 26 million light years away. M83 spiral galaxy also hosts candidate twin binary systems and is located 15 million light years away.
Photo Credits: Wikimedia