We know what the flame of a candle looks like on Earth in 1g and what it looks like in weightlessness. But do we have an idea of what it would look like in Lunar (0.166 g) or Martian (0.38 g) gravity? Did the Apollo astronauts ignite one on the Moon or someone during a parabolic flight? Would the flame look closer to the one in weightlessness or more like on Earth?
There has been some research on flames in 0.38g (using parabolic flights). There are no usable photos in that paper, but:
Cool flames at 0.3g appear qualitatively similar to those at 1g, yet those at μg are radially (presumably spherically) symmetric.
Which is more or less as expected. When you have gravity, you get convection (hot air rising). The speed of convection may be lower, so you get less oxygen transported toward the flame, leading to a lower flame.