Key elements make stars cooler, better for life

[GoodGame]

ScienceShot: For Life's Evolution, Stellar Chemistry Matters
by Bruce Dorminey on 26 July 2012, 5:14 PM | 2 Comments



Planetary scientists agree that a planet's distance from its parent star is of paramount importance for creating conditions where liquid water might spur life. But what about the host star's chemical makeup? A paper in press at The Astrophysical Journal Letters argues that a greater abundance of carbon, sodium, magnesium, and silicon should be a plus for an inner solar system's long-term habitability. That's because the abundance of these elements make the star cooler and cause it to evolve more slowly, thereby giving planets in its habitable zone more time to develop life as we know it. The stellar abundance of oxygen, in particular, seems crucial in determining how long newly formed planets stay in the habitable zone around their host star, the researchers report. If our own sun had a lower abundance of oxygen, for example, Earth would have left the habitable zone a billion years ago, well before complex organisms evolved.

http://news.sciencemag.org/sciencenow/2012/07/scienceshot-for-lifes-evolution-.html?ref=hp

Credit: NASA/Kepler Mission/Dana Berry



Basically the elemental composition of a solar system affects the rate at which the central star goes through its lifespan, affecting the amount of time planets have to evolve life before changes in the star affects the habitable zone's size/location in the solar system.

Interesting that carbon, sodium and magnesium mentioned are either common components or nutrients in life.

Do you think this indicates that life throughout the universe (if present) may tend to be made of the same building blocks?

 

[GoodGame]

Here's the abstract:

The Impact of Stellar Abundance Variations on Stellar Habitable Zone Evolution
Patrick A. Young, Kelley Liebst, Michael Pagano
(Submitted on 19 Jul 2012)

The high quality spectra required for radial velocity planet searches are well-suited to providing abundances for a wide array of elements in large samples of stars. Abundance ratios of the most common elements relative to Fe are observed to vary by more than a factor of two in planet host candidates. This level of variation has a substantial impact on the evolution of the host star and the extent of its habitable zone. We present stellar models of 1 solar mass stars with custom compositions representing the full range of these non-solar abundance ratios. We find that the effects derived from variation over the observed range of [O/Fe] are particularly dramatic. Habitability lifetimes for some classes of orbits can vary by gigayears for the observed range in [O/Fe].

 

[peter grimes]

Do you think this indicates that life throughout the universe (if present) may tend to be made of the same building blocks?

I think so, yes. There are only so many elements, and they all have the same chemical and electronic properties - this should (in my layman's mind) constrain the possible paths the evolution of life might take.

Will any non-terrestrial life be DNA/RNA based? I strongly doubt that. I suspect it's that's a legacy of the contingent history of evolution (first chemical, then biological).

I do, however, suspect that the first life we encounter elsewhere in the solar system will be familiar. I think it's highly likely that early impacts on earth scattered enough early life into the solar system that some of it is probably got a foothold on, say, Mars or the moons of Jupiter. It's stunning to think that the Earth spent at least 2.5 billion years with nothing but simple-life-stew on it.

 

[Cutlass]

I think it makes sense that the highest likelihood of finding planets we could use or planets with life would be around stars similar to the Sun. Stars that form in the absence of any atoms by hydrogen will probably be large because they will take longer to ignite, but then will burn much faster.

 

[GoodGame]

I think so, yes. There are only so many elements, and they all have the same chemical and electronic properties - this should (in my layman's mind) constrain the possible paths the evolution of life might take.

Will any non-terrestrial life be DNA/RNA based? I strongly doubt that. I suspect it's that's a legacy of the contingent history of evolution (first chemical, then biological).

I do, however, suspect that the first life we encounter elsewhere in the solar system will be familiar. I think it's highly likely that early impacts on earth scattered enough early life into the solar system that some of it is probably got a foothold on, say, Mars or the moons of Jupiter. It's stunning to think that the Earth spent at least 2.5 billion years with nothing but simple-life-stew on it.

I'd agree that there's nothing to the OP finding to suggest specific macromolecules of life, just the key elements.

 

[Earth AD 2754]

I never knew that carbon, silicon, magnesium, and sodium can slow down the evolution cycle of stars. And I never knew the amount of oxygen determines how long planets stay in the stars habitable zone.