Eta Carinae is a pair of huge, unstable stars in the Carina Nebula whose giant eruption made it briefly one of the brightest stars in the sky.
At a glance
| type | white supergiant (class A) |
|---|---|
| distance from the Sun | 7,500 light-years (2.3 kpc) |
| its light left it | 7,500 years ago |
| luminosity | 5 million × the Sun |
| radius | 240 × the Sun |
| surface temperature | 9,400 K |
Read off the piece’s own catalogue, the same values it draws with.
About Eta Carinae
In the age before photography, observers in the southern hemisphere, John Herschel among them, watched Eta Carinae brighten until it rivalled the brightest stars, then fade from easy naked-eye view. That Great Eruption threw off a vast amount of material, which now forms the Homunculus Nebula, a double-lobed cloud of gas and dust surrounding the star.
Eta Carinae is a binary. The main star, Eta Carinae A, is a luminous blue variable, one of the most massive and luminous stars known. Its companion, Eta Carinae B, is a hot star on a very elongated orbit. Each time the two swing close together, their fierce winds collide and the system changes sharply in X-rays and in its spectrum.
It lies within the Carina Nebula, a great region of star formation in the southern Milky Way.
What you see in the piece
With HUMAN EYE on from the south it sits in the bright Milky Way in Carina, inside the glowing nebula. The WONDERS (W) frame Eta Carinae A and B together.
Measured or modelled
The star’s true surface is hidden inside its own dense wind, so the temperature on the card describes that outer layer; the star beneath is far hotter. Its masses and the cause of the Great Eruption are modelled, and it is expected to end as a supernova.
Questions
What happened to Eta Carinae?
In its Great Eruption it brightened until it rivalled the brightest stars and threw off the gas that now forms the Homunculus Nebula around it.
How far away is Eta Carinae?
Eta Carinae is 7,500 light-years (2.3 kpc) from the Sun.