Is this how Earth will look when its Sun gets destroyed? Newly discovered planet offers window into our solar system's future
A Jupiter-like planet has narrowly survived the death of its star and scientists are enthused as the discovery offers insight into what will happen to our solar system after the sun collapses.
A team of astronomers found the remains of a dead star, known as a white dwarf, with a surviving exoplanet that resembles Jupiter, reports Popular Science.
The team used a technique called microlensing, in which astronomers wait for two stars to line up perfectly as viewed from Earth and watch to see how the light from the distant star is bent by the gravitational pull of the closer one.
Why should the new discovery excite scientists?
Our Sun is about 4.6 billion years old, and Earth and all the other planets formed at about the same time. What makes this first-ever discovery of a planet orbiting a dead star is that it seems to suggest that some worlds in our solar system will likely survive the sun's violent death about five billion years from now. That makes astronomers and conservation scientists wonder: What are Earth's chances when our Sun dies out eventually?
This newly discovered dead star is a white dwarf star -- which are small stars that are slowly cooling off because they no longer have nuclear fuel to burn. Similarly, when our Sun nears its death, it will likely expand into a red giant, then eject its outer layers leaving only a small, dense core: the white dwarf, reports Space.com.
Looking at this dead star, scientists feel that this remnant represents “what we think will happen to our solar system in about eight billion years,” says Joshua Blackman, an astronomer at the University of Tasmania who led the study. The findings were published in the journal Nature.
Sorry, dear Earth; but at least Jupiter might survive!
As the sun grows into a red giant it will “obliterate Mercury and Venus and quite possibly earth as well on the way,” before it shrinks to a white dwarf, Blackman says, as reported by Popular Science.
Although Earth probably won’t survive the self-destruction of the sun in five billion years, the finding is good news for Jupiter, Saturn and beyond.
“It would have been very easy to lose this planet,” says Juliette Becker, an astrophysicist at Caltech who was not involved in the new research, to Nadia Drake at National Geographic. “Most likely it barely avoided destruction.”
How was this survivor planet discovered?
According to Theresa Machemer of The Smithsonian, astronomers first spotted MOA-2010-BLG-477Lb in 2010 using the Keck II telescope in Hawaii. The research team, led by University of Tasmania astrophysicist Joshua Blackman, detected the sudden brightening of a distant star.
The newfound planet, a gas giant about 40 per cent larger than Jupiter, and its parent star, which orbits near the centre of the Milky Way, were accidentally discovered during a "gravitational microlensing" event in 2010. But according to Space.com, for a long time, however, astronomers had no clue what they were looking at. So, the team followed up years later with the Keck Observatory in Hawaii—which houses one of the largest optical telescopes in the world—to try and observe the star itself. The wait until the conjunction (which had allowed the microlensing) was long but the team waited for it over until the two stars got far enough apart in the sky so they could get a clear look at each, which would sort out how bright and how big they are.
Planet found but where was its star?
Was their telescope not powerful enough? From the microlensing data, the team got “a very strong indication that there’s about a Jupiter mass planet there with a star,” Blackman says. But perplexingly, using the Keck Observatory, they couldn’t spot the star. The telescope should have been powerful enough to see any typical star at that distance. Soon, the team realized that the fact that they couldn’t detect the star wasn’t a failure in the equipment—it meant that the star was simply too dim to see.
Deploying Microlensing technology:
Microlensing requires looking at how light that passed a star has been distorted. In looking at how a star changed the passing light, astronomers can figure out “the geometry of the system,” learning about the mass of a star and potentially the exoplanets that orbit it, Blackman.
It is an indirect way to make a measurement, but “the team did a very thorough analysis” and the study was convincing, says Dániel Apai, an astronomer and planetary scientist at the University of Arizona, who was not involved with the study. Apai heads NASA’s Alien Earths project for exoplanet study.
What makes spotting the White Dwarf special?
First, it’s rare. This is the first time microlensing has been used to find a white dwarf and only the fifth white dwarf ever to be found with an exoplanet. Also, it could be a window into the future of our solar system.
“We expect that Jupiter and Saturn will survive (the death of the Sun), but we didn’t have direct evidence of this being the case,” Blackman says. If Earth hasn’t yet been destroyed by eight billion years’ time, “it will be full of lava lakes and very inhospitable.”