A new study reveals that a comet perihelion or its closest point to the Sun can have a different effect on the HDO levels. HDO is a heavier form of water.
For many years now, scientists have been studying the source of water on Earth. One popular theory is that it may have come from a comet or asteroid that crashed on the planet. But a newly released study goes quite against this theory.
Research on the matter was carried out by an international team of researchers. They were led by Lucas Paganini, a researcher from the NASA Godard Center for Astrobiology. Study results were released last month, in February. They were published in The Astrophysical Journal Letters. The paper was titled as follows: “Ground-based Detection of Deuterated Water in Comet C/2014 (Lovejoy) at IR Wavelengths”.
Research was based on observations of the C/2014 Q2 or Lovejoy comet. Its journey was analyzed with help from a series of infrared observations. The comet perihelion was especially targeted. This is the period in any star’s journey when it is closest to the Sun.
According to the study, this event leaves its traces in the comet. More exactly, it leads to a change of its HDO levels. Also known as D-to-H, this is a heavier form of water. During the study, the researchers looked at Lovejoy’s H2O and HDO levels before and after the 2015 comet perihelion.
And to their surprise, the analysis revealed the following facts. Whilst the H2O levels remain the same, the DHO ones change. More exactly, the comet’s HDO output was 2, almost 3 times higher than before the perihelion.
Paganini, the aforementioned lead, went to offer some details. According to him, the change took them by surprise. But it also highlights the need for more research. This will have to target more than just one comet. And the measurements will have to be taken across differences points, not just in relation to the comet perihelion.
Preferably, the studies would target various comets during different points in their orbital position. Paganini considers that this could help understand all the implications of their discovery.
He also makes reference to the comet-transported water on Earth theory. And according to him, the previous information may be misleading. More exactly, this would become true if the DHO level changes are generally confirmed.
If this holds true, then the assumption that comets contributed with only a small fraction of water when compared to asteroids could potentially be false. At least according to Paganini.
For the moment, the researchers will be trying to establish the reason behind the DHO level modification. They state that the change was quite drastic after the comet perihelion.
A first theory potentially links this phenomenon to solar radiation. This latter may have modified the comet’s surface layers. As such, it could have potentially pushed it into another stage of its usual lifecycle. But for the moment, this is just a theory.
Michael Mumma also released a statement on the matter. He is the NASA Goddard Center for Astrobiology director and a study co-author. According to him, comets can be quite active and dynamic. Especially so when they are closer to the Sun and in the inner solar system.
As such, the study’s simultaneous measurement of the HDO and H2O can eliminate many systematic uncertainty sources. Which further points out the need for more studies and tests on the matter.
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