Chris Marvin ’09 recently co-authored a paper, published last month in the scientific journal Nature, about the discovery of a potentially habitable planet that orbits the closest star to our Sun: Proxima Centauri, a red dwarf in the Centaurus constellation. The planet, which is about 1.3-times larger than the Earth, has been christened “Proxima b.”
"We already know there are thousands of planets orbiting distant stars, but to find an Earth-mass planet in a temperate zone around our nearest neighbor is just mind-blowing," Marvin said.
In Silla, Chile, Marvin helped observe Proxima Centauri using a high-resolution spectrograph installed on a telescope and got a good idea of the length of Proxima b's orbit. The radius of its orbit puts the planet “squarely in the centre of the classical habitable zone,” where temperatures allow for water to remain a liquid on the planet's surface, according to the paper.
Despite potential places to splash around on Proxima b, living on the planet would be a lot different from Earth. For one, it has an 11-day year. Also, astronomers believe Proxima b is likely "tidally locked," meaning that the same side of the planet always faces Proxima Centauri. That also means there are three distinct zones on the planet: the side that faces the star basks in eternal light, the side that faces away is plunged into eternal night, and the band between them is always stuck at dawn or dusk.
That "transitional region... like an eternal twilight," as Marvin called it, "would be a very interesting region to find out about."
Scientists have just that opportunity. Looking toward the future, the paper notes that Proxima b offers the chance to take direct photos and high-resolution spectroscopy of a relatively close interstellar neighbor in the next decades, “and possibly robotic exploration in the coming centuries.” As Whittier College Professor of Physics Glenn Piner observed, it's "the first [exoplanet] to be found that is close enough that we might conceive of sending a spacecraft there during our lifetimes."
Marvin previously worked with Piner researching quasars—extremely bright celestial objects that are powered by black holes that are hundreds of thousands to billions times bigger than our Sun. During that time, Piner noticed that Marvin was an excellent researcher. The datasets from some of the most complex quasars they observed "looked like a confusing mess" when Marvin started, Piner said.
"But he was able to patiently sort them out to reveal how things were moving in the quasar from observation to observation," the professor said.
In 2014, Marvin was also involved in the discovery of two planets orbiting Kapteyn's star, a nearby halo red dwarf. One of those planets, a temperate super-Earth called Kapteyn b, also lies in that star's habitable zone.
Marvin, who is now finishing his Ph.D. in Astronomy at the University of Goettingen in Germany, credits Whittier College with providing him with the foundations to work in astrophysics.
"The great thing is that the professors make sure to put an emphasis on fundamentally understanding concepts, which has helped me tremendously more than just rote learning problems," Marvin added.
You can read more about Proxima b at the Nature website.
Image Courtesy: European Southern Observatory
