Pluto may be well and truly in New Horizons' rearview mirror, but data collected by the probe is still uncovering intriguing new details about the makeup of the distant dwarf planet. Studying images and data captured by the spacecraft during its July flyby, the New Horizons team has discovered a series of snow-capped mountains residing in one of the Pluto's more recognizable features.

The darkened expanses of the region known as Cthulhu stretch almost halfway along Pluto's equator, covering an area larger than Alaska at 1,850 mi (3,000 km) long and 450 mi (750 km) wide. Scientists have attributed the deep reddish tones of the Cthulhu to a covering layer of dark tholins, which are complex molecules that form when methane is exposed to sunlight.

Working with an enhanced color image, the scientists found a mountain range resting in southeast Cthulhu, measuring about 260 miles (420 km) long, with bright, contrasting materials covering the ridge's higher peaks.

The team compared that enhanced color image, which has a resolution of around 2,230 ft (680 m) per pixel, with compositional data from the spacecraft's Ralph/Multispectral Visible Imaging Camera. Seen in purple above, the image shows that the spread of methane ice is almost identical to the bright ice coverage on the mountain peaks, suggesting that the methane in Pluto's atmosphere condenses on the peaks at high altitudes as frost.

"That this material coats only the upper slopes of the peaks suggests methane ice may act like water in Earth's atmosphere, condensing as frost at high altitude," says New Horizons team member, John Stansberry.