Giant planet survives the death of its parent star – A publication in Nature reveals an unusual orbital story

Giant planet survives the death of its parent star – A publication in Nature reveals an unusual orbital story

Dr. Lorne Nelson of Bishop’s University in conjunction with collaborators from around the world have discovered the first planet to orbit the burned out core of a dead star. The observations and analysis were just published in Nature, which is considered to be the world’s premier science journal.

Dr. Nelson, of the Department of Physics and Astronomy, is among the authors of an article describing the discovery of a giant planet roughly the size of Jupiter, although likely to be several times more massive, that is in a very close orbit with its white dwarf companion known as WD 1856+534. The system is located only 80 light years away from the Earth in the constellation of Draco, and the existence of the planet was inferred thanks to observations using NASA’s Transiting Exoplanet Survey Satellite (TESS) in addition to other telescopes during the Summer and Fall of 2019. The white dwarf star is so small that it is not much larger than the Earth and is about seven times smaller than the planet that eclipses it. But more amazingly, the giant planet’s “year” – the time it takes for it to complete a full revolution around the white dwarf star – lasts for a little less than a day and a half (34 hours).

“This is a truly remarkable discovery because the giant planet that we found somehow survived the fiery death of its parent star and subsequently experienced gravitational interactions with other planets that placed it in a very close orbit with the original star’s now ‘dead’ core”, what astronomers refer to as a white dwarf. “These observations may help us understand the future of our own Solar System,” Dr. Nelson explains. “We know that one day as our own parent star (the Sun) starts to die, it too will expand to become a red giant and will likely gobble up Mercury, Venus, and then the Earth. One of the intriguing questions relates to what will happen to the outer gas giant planets such as Jupiter and Saturn after this process. The discovery of WD 1856b, and hopefully many more like it, will go a long way in helping us address this issue.”

Dr. Nelson’s primary contributions to the research were based on calculations that showed that the object orbiting the white dwarf star was most likely to be a giant planet and not another type of celestial object such as a cool, low-mass star (red dwarf) or an even smaller and colder type of object known as a brown dwarf (brown dwarfs are the ‘missing link’ between stars and giant gas planets and typically have masses between about 14 and 75 times the mass of Jupiter). This contribution by Dr. Nelson further demonstrates the level of academic excellence and commitment to research associated with Bishop’s University and its Department of Physics and Astronomy.


Olivier Bouffard
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