Daily Image
10-02-2021
A welcome wobble
| Submitter: | Harish Vedantham |
| Description: | About a year ago, we published the LOFAR discovery of radio emission from a quiescent red dwarf star GJ1151. The properties of the star and emission led us to argue that the radio emission was being induced by an Earth-mass exoplanet in a 1-5 day orbit around GJ1151, as show in the artists impression here (left-panel). If confirmed, this would pave the path for radio telescopes to discover terrestrial exoplanets and determine the strength of the magnetic interaction with their star. Unlike in the solar system, these interactions are highly energetic around red-dwarfs stars and can even melt the mantle of close-in planets. Motivated by our discovery, researchers using data from the Habitable zone Planet Finder and HARPS-N spectrograph have recently detected the wobble of GJ1151 caused by the gravitational tug of a planet. The planet is at least 2.5 Earth masses and is in a 2.02 day orbit - in line with the predictions made from LOFAR data. This provides the first independent corroboration of our result. The plot in the image (right panel) shows the radial velocity, or Doppler shift signature caused by the stellar wobble. Detecting small Earth-size planets using the radial velocity technique is cutting-edge work. We can now reasonably expect other radial velocity instruments to attempt an independent confirmation this exoplanet signal. But more importantly, now that we know the planetary ephemeris, we can efficiently plan follow-up LOFAR observations to detect the anticipated modulation of the radio brightness at the orbital period of the planet. Detection of such a periodicity will prove beyond reasonable doubt that LOFAR is indeed seeing radio emission induced by the exoplanet that is causing the stellar wobble. |
| Copyright: | CC-BY-SA-NC credit: Danielle Futselaar/ASTRON & Mahadevan et al (arXiv:2102.02233) |
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