An image from New Horizons’ Long Range Reconnaissance Imager (LORRI) combined with color data from the Ralph instrument created this global view of Pluto.

(NASA)

Is Pluto’s signature heart-shaped surface feature partly the result of a meteoric impact?

After the dazzled stargazers earlier this year with its high resolution photography of the remote dwarf planet, astronomers have been intrigued by its newly revealed “heart,” fondly referred to by Pluto-philes as the Tombaugh Regio.Paul Schenk, a planetary geologist at the Lunar and Planetary Institute, made waves this week when he told the American Astronomical Society’s Division for Planetary Sciences that he believes a space rock crashed into the western half of the heart of Pluto, giving it its unique indentation. He's basing this idea on an ongoing study about the surface of the Tombaugh Regio, working as part of NASA's New Horizon's science team.

“The clue is the large circular outline far more than half its outline,” Schenk explained to weather.com. “That leaves us naturally to suspect a very large impact crater, now eroded and later filled, forming ices. The other clue is the great depth, which took us by surprise. There are other mechanisms to get a deep basin, but they typically do not form such nice circles. Large degraded impact features occur on Mercury and Mars and even the moon and each one is different. The Caloris Basin on Mercury has some similarities, but of course those are in silica-rich crusts. Pluto's is ice-rich.”

Notre Dame physics professor Justin Crepps, who specializes in studying dwarf planets and does not work with New Horizons, said more analysis was needed before conclusively linking Pluto’s heart to a space rock impact.

“The heart shape is relatively smooth compared to neighboring regions indicating that it is younger than areas riddled with craters,” Crepps said. “This interesting topology is the result of a complicated geologic history, which we are only now starting to study in any detail, and includes perhaps erosion or periods of recent melting. More work is needed in the data reduction process to discriminate between geographic features and light and dark spots versus image frame transmission and analysis effects.”

On the other hand, University of Buffalo associate professor of physics Dejan Stojkovic agreed with Schenk’s hypothesis, saying it sounded “very likely.”

“[The] early solar system [4 billion years ago] was full of rocks and space debris flying around," Stojkovic said."All the planets (and also dwarf planets) of the solar system suffered heavy bombardment in that period before the whole system settled down close to today’s configuration. We do not see that many craters on Earth because of the extensive erosion due to liquid water and wind, but they are very common on other bodies including our own moon.

“Dr. Schenk correctly points out that the circular shape of this crater is typical for the impact craters in the solar system,” Stojkovic added.

In addition, Vanderbilt UniversityAssociate Professor of Astronomy David Weintraub thought Schenk made a "reasonable suggestion," but had questions of his own about the dwarf planet.

"The Tombaugh Regioappears to have far fewer small craters than the surrounding areas, and of course the color of this region is different from some of the surrounding regions," Weintraub observed. "So I want to know what the composition is and why this region is relatively crater free."

In response, Schenk surmised that all that following the impact, all that was left was a "frost built up over millions of years,"

"It was basically a topographic basin filled in with nitogen, methane and carbon monoxide," he explained. "All frozen out on the surface and they filled it because that's its low point, it accumulated there."

Schenk hopes to have more answers when the New Horizons team releases a report on the surface in the months to come.

MORE ON WEATHER.COM: Images of Pluto from New Horizons

New Horizons scientists made this false-color image of Pluto using a technique called principal component analysis to highlight the many subtle color differences between Pluto's distinct regions. The image data were collected by the spacecraft’s Ralph/MVIC color camera on July 14 at 11:11 AM UTC, from a range of 22,000 miles (35,000 kilometers). (Credits:NASA/JHUAPL/SwRI)