YZ CETI B - SCI & TECH
News: Why
is a star-planet pair just 12 light-years away emitting radio signals?
What's in the news?
● The
discovery was made by Jackie Villadsen from Bucknell University, Pennsylvania,
and Sebastian Pineda from the University of Colorado, Boulder, using the Karl
G. Jansky Very Large Array radio
telescope in New Mexico. They published their findings in the journal
Nature Astronomy on April 3.
Key takeaways:
● They
had to make multiple rounds of observations before they could detect the radio
signals from the star YZ Ceti, which
seemed to match the orbital period of the planet YZ Ceti b. From this, they
deduced that the signals were a result of the interaction between the planet’s
magnetic field and the star.
YZ Ceti b:
● YZ
Ceti b is a rocky, earth-sized exoplanet
(a planet that orbits a star other than our sun) rotating around a small red
dwarf star, YZ Ceti.
● It
is barely 12 light-years from Earth,
a handshake distance in astronomical terms.
Why is YZ Ceti b unique?
● Astronomers
are excited because they have detected a repeating
radio signal from this exoplanet that suggests the presence of a magnetic field
– one of the prerequisites for a habitable planet – around it.
Why does the magnetic field 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.
● 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.
● Magnetic
field is important because the survival
of a planet’s atmosphere may well depend on its having, or not having, a
strong magnetic field, since the field protects its atmosphere from being
eroded by the charged particles blowing in from its star.
What’s the implication for YZ Ceti b?
● This
is borne out by the small orbit of YZ Ceti b - the astronomers determined that
the planet takes just a couple of earth days to circle its star.
Exoplanets:
● An
exoplanet is a planet that orbits a star
other than our sun.
● Since
the mid-1990s, astronomers have found hundreds of planets orbiting stars
similar to the sun, suggesting that planet formation in the universe’s galaxies
is more common than scientists ever reckoned.
● Data
from space-science missions such as Kepler, Gaia, and the James Webb space
telescopes suggest the existence of possibly more than 300 billion planets in
the Milky Way Galaxy alone.