Lucky observers with clear skies who also happen to live on a line drawn between Porthcawl on the Welsh coast through just south of Birmingham and on to the Lincolnshire Wolds can witness a grazing lunar occultation of naked-eye star Eta (η) Geminorum by the rising 18-day-old waning gibbous Moon just before 10pm GMT on 15 November 2019.
If you’re bemoaning the current dearth of bright planets in the evening sky, or light pollution prevents you from viewing a multitude of spring galaxies, don’t give up – there are always attractively coloured double and multiple stars to view. Join us on a tour of the Northern Hemisphere constellation of Boötes (pronounced Bo-oh-tees), the Herdsman, easily located due to its brightest star, Arcturus.
A team of astronomers led by the University of Arizona has discovered a planet known as HD 131399Ab in a unique position between three stars about 340 light-years from Earth. The finding shows that massive planets may be found on long and possibly unstable orbits in multi-star systems, expanding current models of how star systems and their planets form.
Exoplanet KELT-4Ab, about one and a half times the size of Jupiter, orbits the main star of a three-star system every three days. The system’s other two stars orbit each other once every 30 years while simultaneously orbiting the main star — and the planet — once every 4,000 years. The triple star system lies about 685 light-years from Earth.