More Suns, More Fun?

Until the late 1980’s the thought of other stars having planets, much less entire planetary systems, was the stuff of science fiction, not science.

Then bang, the first one was found, and a paper published in 1988 by Canadian astronomers Bruce Campbell, Gordon Walker, and Stephenson Yang. Unfortunately for the study authors, their data was met with so much skepticism they retracted the paper, only to be vindicated in 2003. Their discovery might have earned them the Nobel Prize had they stuck to their guns. Such is life in big-time astronomy.  Now we have confirmed over 5000 planets orbiting other stars.

It’s common for stars to have one or more companion stars in their life. Most stars are born in a family of siblings, a cluster.  Of the more than 5000 exoplanets found, astronomers have so-far confirmed 217 associated with more than one star.  Our Sun was part of a cluster billions of years ago, but the family has long since split up and the Sun has no sibs to hang out with.  Are we missing out? What would life be like if we had two, three, or more stars in the hood?

Let’s pick one sibling star for our Sun, make it a star similar to our Sun, at the distance of Uranus, 1.8 billion miles. That’s 19.8 Astronomical Units (AU), or 19.8 times the Earth-Sun distance.

Of course, much depends on how Earth interacts. Let’s say Earth still orbits the Sun, with the sib and the Sun orbiting a center of gravity somewhere between them. We do not know if other planets exist in this scenario, but I suspect they do, just in different forms.

From a distance of 19.8 AU the sib is way dimmer than the Sun, but still extremely bright.  So bright it’s brilliant in the daytime sky and painful to look at. Bright enough to cause shadows at night, when it’s in the nighttime sky – light pollution, eh? Plant and animal life would have evolved to adjust for the differential light. We might see two shadows in daytime. Fortunately, Earth’s temperature would not be significantly affected, unless the sib and Sun had orbits that took them much closer to each other from time to time. We would likely have a different planetary organization. Our night sky might show off more gas biggies like Uranus, maybe close enough to see its disk with the naked eye!

Alas, 19.8 AU is too close according to most planetary scientists. Conditions would be too unstable for Earth-like planets to form. The current thinking is a minimum of 100 AU. Still, it would be interesting.

More than one sib and orbital dynamics create an even more unstable situation for planet formation, much less life.

What’s in the Sky?

Last week’s Sun Party at Tye Preston Memorial Library was a success, with participants observing white light and H-alpha filtered views of the Sun. Club member Larry Wells spoke about solar weather and Sunquakes.

May 29; pre-dawn; east-southeast: Jupiter and Mars are in conjunction.