Radio revelations:

Discovering our galaxy’s hidden planets

Benjamin Pope, UQ

Slides available at
benjaminpope.github.io/talks/brisscience/brisscience

Planets

More planets are being discovered all the time!

Like Moore's Law, Mamajek's Law:

Number of known exoplanets double every 27 months

Radial Velocity

Total: 877

The first exoplanet: 51 Pegasi b, Mayor & Queloz (1995)

Nobel Prize in 2019: Mayor & Queloz for 51 Peg b discovery

Direct Imaging

Total: 54

Transits

Total: 3401

Exoplanet-style transit light curve of Venus from James Gilbert on Vimeo.

My first planet, using Kepler: EPIC 212521166 b!

JWST

The newly launched James Webb Space Telescope hopes to search atmospheres of nearby planets for signs of habitability

Red Dwarfs

Radio Astronomy!

Total planets:?

Many papers have discussed low-frequency searches for exoplanetary radio emission, with no detections so far.

Theorists now say that expanded ionospheres of hot Jupiters might self-absorb this emission down to undetectable levels.

The Square Kilometre Array (SKA) is a billion-dollar project to build a massive ~ GHz frequency SKA-Mid array in the Karoo Desert in South Africa and a ~ 100 MHz SKA-Low array in the Murchison Desert in Western Australia.
What can the SKA do for exoplanet science?

LOFAR

The LOw Frequency Aperture Array (LOFAR) in the Netherlands has been surveying the northern sky as a LOFAR Two-metre Sky Survey LoTSS.
Cross-matching circularly-polarized sources with nearby red dwarfs sample we obtain many matches

GJ 1151

Red dwarfs are known to be very variable in the radio, with wideband, circularly polarized flares.

... but GJ 1151 is inactive and this emission is steady during the epoch it is detected.

Scaled up from Jupiter-Io?

RV Followup (Pope+ 2020, Mahadevan+ 2021)

The Whole Sample

Güdel-Benz Diagram

Active stars

Quiescent stars

The Future

As LOFAR continues its survey we expect dozens more detections.

With the SKA - hundreds!

Joint LOFAR+TESS observation to observe flaring stars - can we constrain CMEs?
Follow up all LOFAR candidates with RVs and look for transits!
Finally the dawn of exoplanet radio astronomy (!?)