Astrobites Daily Paper Summary

Are Extrasolar Worlds More Likely to Be Water-rich?
Link: http://astrobites.org/2015/03/06/are-extrasolar-worlds-more-likely-to-be-water-rich/

Water is all around us. From the vast oceans covering the planet to the cells of our body, we are completely surrounded by this abundant molecule. Life as we know it needs water to survive and thus it is very important to us. When considering the existence of extraterrestrial life, scientists, based on our current observations and understanding, believe that water is most likely necessary for the development and propagation of life, and thus planets that have water are more likely to harbor life.

Though we are surrounded by so much water here on Earth, we never seem to think about where it came from. It most likely was deposited over time by water-rich asteroids that impacted with the Earth after its formation. Since the Earth formed closer to the Sun than the asteroids, less water remained in the final planetary formation. The asteroids formed in a region with a lower temperature and therefore had more water incorporated into their final form.

When considering the amount of water that exists in extrasolar systems, we have to consider the conditions under which the solar systems formed. Short-lived radioactive isotopes caused much of the heating of the solar system and thus determined the loss of the amount of volatile substances such as water. However, the amount and concentration of these isotopes is thought to vary across systems and thus some systems may have more volatiles like water.

We can also see that the amount of water varies depending on the distance away from the star because of the difference in temperature.