         There exists a region around a star inside which a planet may be considered habitable by life as we understand it. Habitability can depend on many factors but the main one is the potential for liquid water to exist on the surface of an Earth-sized, rocky planet. This therefore depends primarily on the distance of the planet from its host star. Too close and the water will boil, too far and it will freeze. Stars that are smaller and cooler than our Sun (such as M-dwarfs) will have habitable zones that are much closer in, which means potentially habitable planets around them will have shorter orbital periods than a year.
         """
       figure: "./images/mini-course/14-HabitableZone.png"
-      figure_credits: "NASA"
+      figure_credits: "Image credit: NASA"
 
   }
 

        Stars are mostly made of hydrogen, which is also true for some gas giant planets such as Jupiter. The difference is that stars are massive enough to ignite nuclear fusion of hydrogen into helium in their cores. The smallest stars are roughly 75 times more massive than Jupiter, and the largest planets are about 13 times more massive than Jupiter.
        """
      figure: "./images/mini-course/12-star-v-planet.jpg"
      figure_credits: "NASA"

  }


        The radial velocity method has been used to discover hundreds of exoplanets to date, however it has one major disadvantage; it cannot be used to determine the angle of the planetary system to our line-of-sight, so perhaps we are only seeing a small fraction of the star’s movement? This means that only a minimum measurement of the star’s speed can be calculated, leading to only a minimum possible value for the mass of the exoplanet.
        """
      figure: "./images/mini-course/16-radial-velocity.jpg"
      figure_credits: "Image credit: UCAR Center for Science Education"

  }

