The Goldilocks Zone, according to the Wikipedia, is:
- In astronomy and astrobiology, habitable zone (more accurately, circumstellar habitable zone ) is the scientific term for the region around a star within which it is theoretically possible for a planet with sufficient atmospheric pressure to maintain liquid water on its surface.
In the past this has been fairly easy to determine as, where ever the Earth was in reference to a yellow dwarf star, that was the habitual zone, and all other calculations could be made from this generality.
Well Space.Com has an article that seems to throw a bit of a monkey wrench in to the mix.
In a recent article:
- Now scientists have redefined the boundaries of the habitable zone for alien planets, potentially kicking out some exoplanaets that were thought to fall within it, and maybe allowing a few that had been excluded to squeeze in.
What surprised me however was the redefined low end (how close a planet can be) for an Earth style system was .99 AU. Earth at 1 AU just barely makes the cut as a world almost too hot to maintain liquid water without it boiling away.
Many astrobiologists are surprised at the closeness of Earth to the inside edge. Plus with the new definition, many planets now fall into a to hot class not likely to harbor life.
Read the Dvice article
