Planetary scientists have calculated.............
and found the standard star has about two planets in the “Goldilocks zone” — the distance from the star where liquid water, crucial for life, can exist.
Sad to say, the so called Goldilocks Zone is another aspect in the attempt to popularise astronomy.
Needless to say, it is completely unnecessary. The elements for an Earth like world are chemistry and mass. Venus has an acidic atmosphere because of its chemistry, while Mars has little or none because of its gravity. Strangely, it it looking likely that Mars may have had a period in its distant past when, inspite of its mass, it did retain an atmosphere of sorts and hosted flowing water. That atmosphere would have been funnelled away when Deimos was attracted away from the asteroid field and into Mars Orbit.
Further evidence can be noted from the observations that Mercury hosts pockets of ice.