Youngest Extra-Solar Planet Discovered
University of Hertfordshire astronomers, Dr Maria Cruz Gálvez-Ortiz andDr John Barnes, are part of an international collaboration that hasdiscovered the youngest extra-solar planet around a solar-type star,named BD+20 1790b.
The giant planet, six-times the mass of Jupiter, is only 35 millionyears old. It orbits a young active central star at a distance closerthan Mercury orbits the Sun. Young stars are usually excluded fromplanet searches because they have intense magnetic fields that generatea range of phenomena known collectively as stellar activity, includingflares and spots. This activity can mimic the presence of a companionand so can make extremely difficult to disentangle the signals ofplanets and activity.
Dr Maria Cruz Gálvez-Ortiz describing howthe planet was discovered said: “The planet was detected by searchingfor very small variations in the velocity of the host star, caused bythe gravitational tug of the planet as it orbits – the so-called“Doppler wobble technique”. Overcoming the interference caused by theactivity was a major challenge for the team, but with enough data froman array of large telescopes the planet’s signature was revealed.”
Thereis currently a severe lack of knowledge about early stages of planetevolution. Most planet-search surveys tend to target much older stars,with ages in excess of a billion years. Only one young planet, with anage of 100 million years, was previously known. However, at only 35million years, BD+20 1790b is approximately three times younger. Thedetection of young planets will allow the testing of formationscenarios and to investigate the early stages of planetary evolution.
BD+201790b was discovered using observations made at different telescopes,including the Observatorio de Calar Alto (Almería, Spain) and theObservatorio del Roque de los Muchachos (La Palma, Spain) over the lastfive years. The discovery team is an international collaborationincluding: M.M. Hernán Obispo, E. De Castro and M. Cornide (UniversidadComplutense de Madrid, Spain), M.C. Gálvez-Ortiz and J.R. Barnes,(University of Hertfordshire, U.K.), G. Anglada-Escudé (CarnegieInstitution of Washington, USA) and S.R. Kane (NASA ExoplanetInstitute, Caltech, USA). The discovery has just been published in theAstronomy & Astrophysics journal.