Astronomers unravel the mystery of the ‘Dragon’s Egg’ nebula

Subject: Science and tech

Section: Space sector

Context:

Two large stars residing inside a spectacular cloud of gas and dust nicknamed the “Dragon’s Egg” nebula have presented a puzzle to astronomers.

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What has the new research found?

Researchers now appear to have resolved this mystery while also explaining how the relatively few massive stars that are magnetic got that way.
The bigger star apparently gobbled up a smaller sibling star, and the mixing of their stellar material during this hostile takeover created a magnetic field.
This merger was likely very violent.
When two stars merge, material can be thrown out, and this likely created the nebula we see today.
Computer simulations previously had predicted that the blending of stellar material during such a merger could create a magnetic field in the combined star born in this process.
These two stars – gravitationally bound to each other in what is called a binary system – are located in our Milky Way galaxy about 3,700 light-years from Earth in the constellation Norma.
A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).
The magnetic star is about 30 times more massive than the sun.
Its remaining companion is about 26.5 times more massive than the sun.
They orbit at a distance from each other varying from seven to 60 times the distance between Earth and the sun.

What is Egg Nebula?

The Dragon’s Egg is so named because it is located relatively near a larger nebula complex called the Fighting Dragons of Ara.
The stars inside the Dragon’s Egg appear to have started out 4-6 million years ago as a triple system – three stars born at the same time and gravitationally bound.
The triple system’s two innermost members included a larger star – perhaps 25 to 30 times the mass of the sun – and a smaller one – maybe five to 10 times the sun’s mass.

Many sun-sized stars generate magnetic fields:

For low-mass stars like our sun, convective heating – like the movement of hot water in a radiator in your home – creates a movement of stellar material.
This in turn creates a dynamo effect which induces a magnetic field.
However, for massive stars – greater than eight times the mass of our sun – different heating effects are in play, and so explaining the presence of magnetic fields for these types of stars is more tricky.