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Eta Carinae

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Eta Carinae is a very special star system.

Eta Carinae
Eta Carinae

It is located far away in the constellation Carina. This system contains at least two stars working together. These stars have a combined brightness much higher than our Sun. In fact, they are over five million times brighter than the Sun. This system is part of a huge area called the Carina Nebula.

The Carina Nebula in the constellation of Carina
The Carina Nebula in the constellation of Carina

It is a very busy and bright place in our sky.

The system works because the two stars orbit each other. They follow an eccentric orbit, which means their path is not a perfect circle. This orbit takes about 5.54 years to complete. One star is a luminous blue variable, or LBV. An LBV is a star that changes its brightness over time. This primary star is very unusual and has lost much of its mass.

Eta carinae orbit
Eta carinae orbit

The second star is also very hot and bright. It is likely an O-type star that is 30 to 80 times as massive as our Sun.

People have watched this star for a very long time. Edmond Halley made the first firm record of it in 1677. He called the star Sequens, which means "following."

Historical visual lightcurve for Eta Carinae (1686 - 2014)
Historical visual lightcurve for Eta Carinae (1686 - 2014)

In 1837, the system began a period called the Great Eruption. During this time, it became the second-brightest star in the night sky. It was even brighter than the star Rigel. The star then faded and became hard to see with just your eyes.

There are many amazing facts about this star system. The Great Eruption threw out material that formed the Homunculus Nebula.

3D Homunculus Nebula
3D Homunculus Nebula

This nebula looks like two orange lobes around the stars. The stars also produce ultraviolet laser emission. This is the only star known to do this. In 1892, there was another smaller eruption.

Eta Carinae
Eta Carinae

Since about 1940, the star has been getting brighter again. By 2014, it was brighter than magnitude 4.5.

You can connect this star to things you might see at night. If you live far south of the equator, you might see it. For example, people in Johannesburg can see it.

EtaCarinaeStarSystem-3Views-XRayOpticalIR-20140826
EtaCarinaeStarSystem-3Views-XRayOpticalIR-20140826

However, people in places like Cairo cannot see it. It is also near a meteor shower called the Eta Carinids. This shower happens every January. Watching Eta Carinae is like watching a giant cosmic firework show in slow motion.

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🖼️ Images & Media (20)
File:Eta Carinae.jpg
Eta Carinae.jpg
File:Historical visual lightcurve for Eta Carinae (1686 - 2014).png
Historical visual lightcurve for Eta...
File:Eta Carinae light curve.png
Eta Carinae light curve.png
File:The Carina Nebula in the constellation of Carina.jpg
The Carina Nebula in the constellation of...
File:EtaCarinaePos.svg
EtaCarinaePos.svg
File:Hubble composite of Eta Carinae.jpg
Hubble composite of Eta Carinae.jpg
File:Eta Carinae light echo.gif
Eta Carinae light echo.gif
Cosmic Fireworks in Ultraviolet Eta...
File:Stars similar to Eta Carinae in nearby galaxies.jpg
Stars similar to Eta Carinae in nearby...
File:EtaCarinaeStarSystem-ChandraXRayObservatory-20140826.jpg
EtaCarinaeStarSystem-ChandraXRayObservator...
File:NGC 3372d.jpg
NGC 3372d.jpg
File:3D Homunculus Nebula.jpg
3D Homunculus Nebula.jpg

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