It plays an unexpected role in planetary temperature, researchers found:
While most research about the habitable zone has focused on a star’s brightness (as temperature dictates whether water on a planet could be liquid, ice or gas), new research is showing that this is an extremely simplified and naive picture. The true test for whether or not a planet could host life may, in fact, rest in the most boring of gases: nitrogen…
The researchers behind the simulations in this new study found that nitrogen plays a huge role in determining the overall temperature of a planet — and, therefore, its habitability. What’s even more complicated: it’s not a simple relationship, more nitrogen doesn’t necessarily just make a planet warmer.
For example, if a planet’s atmosphere isn’t too thick and there’s lots of water present, adding nitrogen can cause significant heating, because the added atmospheric pressure increases the effectiveness of greenhouse gases like carbon dioxide and water vapor. On the other hand, on a relatively dry world, more nitrogen more easily scatters starlight away, leading to dramatic cooling.
The end result is that two worlds orbiting identical stars with identical orbits with similar surfaces but different amounts of nitrogen can have dramatically different temperatures and can be seriously hard to predict.
Paul Sutter, “We don’t really understand the habitable zones of alien planets” at Space.com
The paper is open access.
Brush up on your nitrogen: