θ¹ Orionis A is one of the four Trapezium stars in the Orion Nebula, a hot young star whose brightness dips regularly as a companion passes in front of it.
At a glance
| type | blue-white star (class B) |
|---|---|
| distance from the Sun | 1,340 light-years (412 pc) |
| its light left it | 1,340 years ago |
| luminosity | 25,000 × the Sun |
| radius | 6 × the Sun |
| surface temperature | 30,000 K |
Read off the piece’s own catalogue, the same values it draws with.
About θ¹ Orionis A
The four brightest stars of the Trapezium are labelled A to D, in order of their position on the sky rather than their brightness. θ¹ Orionis A is the westernmost of the four, a hot young star at the heart of the Orion Nebula.
It is an eclipsing binary: a fainter companion passes in front of it at regular intervals, and the system dims briefly. It also has a more distant companion seen by other methods, so like most stars this massive it does not live alone.
Together with its neighbours, θ¹ Orionis A belongs to the Orion Nebula Cluster, a crowd of young stars only recently born from the cloud.
What you see in the piece
Fly to the Orion Nebula and θ¹ Orionis A is one of the four blue-white stars of the Trapezium; the glowing gas around them is lit mostly by their brighter neighbour C.
Questions
What are the Trapezium stars?
They are four bright young stars, labelled A to D, at the centre of the Orion Nebula, arranged in a small trapezium that a small telescope can show.
How hot is θ¹ Orionis A?
Its surface is about 30,000 K.