Tag Archives: WASP-43

The IAU names more WASP exoplanets

The International Astronomical Union is periodically running contests to allow young people worldwide to name exoplanets, including those found by the WASP project.

Results of the 2022/23 naming process have just been announced.

The star WASP-19 is named Wattle (a genus of 1000 species of shrubs and trees native to Australia) while planet WASP-19b is Banksia (a genus of Australian wildflowers of medicinal and cultural importance to indigenous Australians).

The star WASP-43 is named Gnomon (after the astronomical instrument) while planet WASP-43b is Astrolábos (Greek for the astronomical instrument used in navigation).

The star WASP-63 is named Kosjenka while planet WASP-63b is Regoč (the names being characters in a popular Croatian fairy tale).

The star WASP-69 is named Wouri while planet WASP-69b is Makombé (being a major river in Cameroon and its tributary).

The star WASP-121 is named Dilmun (the Sumerian name of an ancient civilisation of the Bahrain archipelago) while planet WASP-121b is Tylos (the ancient Greek name for Bahrain island.).

The star WASP-166 is named Filetdor while planet WASP-166b is Catalineta (being a sea-serpent and heroine from the Mallorcan folktale “Na Filet d’Or”).

Magnetic activity on planet-host stars

One interesting question is whether close-in hot-Jupiter planets have an effect on the magnetic activity of the host star. There have been suggestions that star–planet interactions might increase magnetic activity on the star, or that tidal interactions might decrease it. Further, if mass lost from planets forms an absorbing cloud around the star, then it might reduce observable signs of magnetic activity, even if it doesn’t affect the magnetic activity itself.

A new paper by Daniel Staab et al, led by the Open University, investigates the issue by looking for markers of magnetic activity in spectra of host stars WASP-43, WASP-51, WASP-72 and WASP-103. In the following plot, RHK is a marker of magnetic activity, plotted against the temperature (B–V) of the star. The green dots are a large sample of field stars, while the four WASP host stars are labelled in red.

Chromospheric activity on planet-host stars.

The result is that at least one planet-host, WASP-43, has an abnormally high degree of magnetic activity, while another one, WASP-72, has abnormally low magnetic activity. Staab et al conclude that there is no single factor explaining the differences, and that more than one effect might be in play. As often, a much larger sample of data is needed to investigate the issue.