NASA’s Kepler telescope delivers new planetary discovery from the grave
Following the development of specialised analysis methods, candidate signals were finally uncovered last year using a new search algorithm presented in a study led by Dr Iain McDonald, at the time an STFC-funded postdoctoral researcher, working with Dr Kerins. Among five new candidate microlensing signals uncovered in that analysis one showed clear indications of an anomaly consistent with the presence of an orbiting exoplanet.
Five international ground-based surveys also looked at the same area of sky at the same time as Kepler. At a distance of around 135 million km from Earth, Kepler saw the anomaly slightly earlier, and for longer, than the teams observing from Earth. The new study exhaustively models the combined datasets showing, conclusively, that the signal is caused by a distant exoplanet.
“The difference in vantage point between Kepler and observers here on Earth allowed us to triangulate where along our sight line the planetary system is located”, says Dr Kerins.
“Kepler was also able to observe uninterrupted by weather or daylight, allowing us to determine precisely the mass of the exoplanet and its orbital distance from its host star. It is basically Jupiter’s identical twin in terms of its mass and its position from its Sun, which is about 60% of the mass of our own Sun.”
Later this decade NASA will launch the Nancy Grace Roman Space telescope. Roman will find potentially thousands of distant planets using the microlensing method. The European Space Agency’s Euclid mission, due to launch next year, could also undertake a microlensing exoplanet search as an additional science activity.
Dr Kerins is Deputy Lead for the ESA Euclid Exoplanet Science Working Group. “Kepler was never designed to find planets using microlensing so, in many ways, it’s amazing that it has done so. Roman and Euclid, on the other hand, will be optimised for this kind of work. They will be able to complete the planet census started by Kepler.” he said.
“We’ll learn how typical the architecture of our own solar system is. The data will also allow us to test our ideas of how planets form. This is the start of a new exciting chapter in our search for other worlds.”