150 million light years away, in the constellation Perseus, a new discovery has been made. There, a white dwarf star named GD 61 has been shown to support a planetary system. Just last week, researchers at Cambridge and the University of Warwick published an article with convincing evidence that the system can support Earth-like planets.
This image shows the white dwarf star GD 61. Image credit: Centre de Données astronomiques de Strasbourg / SIMBAD via Sci-News.com.
For a planet to be Earth-like, it must have a similar size and composition. If the planet is then located in the habitable zone of a star similar in size to our sun, it would be hard NOT to imagine life there. The problem is, we aren’t sure just how common other “Earths” are!
To determine this requires years of careful observation, noting how many of these exoplanets we are able to find. This article, published in the journal Science, was the first to find a star system (outside our own) that we could prove contained planets made of water and rocky material.
An artist’s interpretation of what Earth-like planets may look like. Photo: Robert Hurt via solstation.com.
The researchers used Hubble, Keck I, Keck II, and NASA’s FUSE to detect a large asteroid orbiting the star. It was large and approximately 26% water by mass. It is very similar in size and composition to Ceres, the largest asteroid detected so far in the Kuiper Belt (of our own solar system). They hypothesize that it was formed from the breakup of a small, terrestrial planet like Earth, that met its demise as its star died. Even if it was not, scientists say it is impossible that the system could contain planetessimals so large without accreting planets.
This is an artist’s impression of a rocky and water-rich asteroid being torn apart by the strong gravity of the white dwarf star GD 61. Image credit: Mark A. Garlick, Space-art.co.uk / University of Warwick / University of Cambridge via Sci-News.com
These hypothetical planets (which they are now trying to detect, but may have been demolished) would have orbited a sun-like star and have been composed of water and heavy elements like oxygen, silicon, and magnesium: key ingredients for life! It had not been found earlier because most research is conducted on living star systems (ones that still actively fuse atoms in their cores; i.e. not white dwarves). Perhaps only a few billion years ago, there could have been a planet with abundant life, just like ours!
The future of our sun: a red giant. Photo credit: Karen aka CharmedQuarkGirl on Flickr.
In fact, this extrasolar system gives researchers an eerie look into our own future. In approximately 12 billion years, this might be what our neighborhood looks like. As the sun progresses through its life, it will turn in to a red giant and then a white dwarf, just like GD 61. Who knows what future civilizations will think if they spot the remnants of our home floating around a dead star?
Sources:
http://en.wikipedia.org/wiki/GD_61
