From the November 2010 issue

What is the largest star known, and how far out would its habitable zone be?

Samuel Heinitz, Edmond, Oklahoma
By | Published: November 19, 2010 | Last updated on May 18, 2023
The habitable zones of the star with the largest diameter (VY Canis Majoris) and of the most massive star known (R136a1) dwarf that of our Sun. Both of these stars’ habitable zones are farther out than our solar system’s Kuiper Belt (the region of icy, rocky bodies just beyond Neptune’s orbit). In fact, R136a1’s would extend into the Oort Cloud — a region no spacecraft has yet explored. Astronomy: Roen Kelly

One possibility, VY Canis Majoris, is so big that if you placed it in the Sun’s position at the center of the solar system, it would extend to Saturn’s orbit!

R136a1 is a good candidate. Scientists recently announced that this star might be some 265 times the Sun’s mass.

For VY Canis Majoris, the habitable zone is between roughly 600 and 1,200 astronomical units (the Earth-Sun distance, or AU) from the star. For R136a1, the habitable zone is located about 2,500 to 5,100 AU from the star.