Context: Astronomers have detected a repeating radio signal from an exoplanet, YZ Ceti b, suggesting the presence of a magnetic field — one of the prerequisites for a habitable planet — around it.
What is YZ Ceti B:
- YZ Ceti b is a terrestrial exoplanet that orbits an M-type star.
- Its mass is 0.7 Earths.
- It takes 2 days to complete one orbit of its star.
- Its discovery was announced in 2017.
What is a Magnetic Field?
- The magnetic field is a field, produced by electric charges in motion.
- It is a field of force causing a force on a material in the vicinity of the field.
- Magnetic field does not require any medium to propagate – it can propagate even in a vacuum.
- The energy storing capacity of the magnetic field is greater than the electric field.
- The earth also has its natural magnetism which protects it from solar waves from the sun.
Why does the magnetic field of this exoplanet matter?
- Just as energy surges from the sun sometimes disrupt telecommunications on earth and damage orbiting satellites, intense bursts of energy from the YZ Ceti star-exoplanet exchange produce spectacular auroral lights which we can see in the form of radio waves.
- These radio waves, strong enough to be picked up on earth, confirmed the existence of an exoplanetary magnetic field.
- Such signals can only be produced if the exoplanet orbits very close to its parent star and has its own magnetic field to influence the stellar wind and generate the signals.
- YZ Ceti b has a small orbit.
- To have an atmosphere and sustain water, a planet has to be at a certain distance from its star (in orbits said to be in the star’s “Goldilocks zone”), or it will get burnt.
SOURCE: THE HINDU, THE ECONOMIC TIMES, PIB