Without water, we will not be able to create a research base on the Red Planet, but the main ice deposits are concentrated closer to the poles, and here we will have to withstand even low temperatures. Now astronomers have found water frost at the equator of Mars, in the volcanic calderas of the Pharsida Province.

Some of the highest and largest volcanoes in the Solar System are located in the Pharsida Province of Mars. It rises above the surrounding plains for approximately five kilometers. Its width is approximately five thousand kilometers. There are low shield volcanoes such as the Arsia and Askriyska mountains, which are about 18 kilometers high, Pavlina Mountain (14 kilometers) and the Keravnsky Dome (nine kilometers high). The extinct Olympus volcano, which is 21 kilometers high and is a record size, is also located here.

Throughout the history of the Red Planet, the Farsid Province has been the most active volcanic region. The youngest solidified lava there is about 2.4 million years old. Although Mars is seismically active, we do not currently see any volcanic activity at Pharsida volcanoes.

The region continues to play an important role in the life of the planet. It lies in the path of the large-scale annual “migration” of water vapor between the hemispheres. Judging by the large amount of water vapor above Pharsida, there is a constant exchange of water between the regolith and the atmosphere. But due to the relatively lower humidity and higher temperature at the surface, scientists did not expect this water to “fall” as frost at these latitudes.

With the help of the Trace Gas Orbiter, astronomers were able to see morning frost on volcanoes in the Pharsid Province for the first time. The results of the research were published in the journal Natural Geology.

The authors of the scientific study mainly used data from the CaSSIS tool, a camera that takes color and stereo photographs. As the scientists explain, the blue areas at the bottom and edges of the caldera appear in the morning hours of the cold season (around 7 a.m. Mars time) and disappear by noon. No blue “haze” was visible on well-lit slopes.

The researchers noted that frost areas are geologically related to bright areas. It’s probably dust accumulation. Due to small particles, such a surface must cool more at night and warm up more slowly in the morning. Additionally, small particles and the overall porosity of such a layer provide more opportunities for the formation of icicles. In general, conditions are suitable for frost formation.

The frost formation cycle clearly depends on temperature fluctuations in the Martian day and season. However, it is not possible to determine the composition of these sediments based solely on data from the CaSSIS instrument. For this, the study’s authors used computer simulation.

It turned out that the calculated temperature near the surface of the Red Planet during these periods was too high for the formation of ice from carbon dioxide. Additionally, other orbiters have not recorded dry ice in this region of Mars. Therefore, the authors are inclined to the version that it is water.

As for frost thickness, estimates vary by two orders of magnitude: from units to hundreds of micrometers. If we assume that the frost thickness is about 10 micrometers (one hundredth of a millimeter), it turns out that about 150 thousand tons of water accumulates in the Farsida volcanoes every day. In general, this is not much – there are trillions of tons of water in the atmosphere of Mars during warm seasons.

Judging by the absence of characteristic traces on the slopes of the caldera, frost does not play a role in the evolution of the relief. But it is important for us to understand the microclimatic conditions in certain regions of Mars in order to better plan missions, both with the participation of automated vehicles and with the participation of humans.