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Summary of Current Information
 A. The Parent Star B. The Exoplanet

### II. Is This Planet Potentially Habitable?

Before taking a look at some of the physical characteristics of our exoplanet, let's see where it would be graphed on a plot of potentially habitable planets as introduced by Kasting, Whitmire and Reynolds [ICARUS, 101, 108-128 (1993).]

 Caption: The mass of the star in solar masses is plotted against the distance the exoplanet is from the star. Note that the radii of stars of different spectral types are also indicated by the corresponding letters (O, B, A, F, G, K, M). These letters show the location of the zero subdivision of each spectral type, thus F5, for example, is between F0 and G0 (and not between A0 and F0). The approximate size and position of the planets of our solar system are shown along the horizontal line corresponding to a star with one solar mass (the Sun) and are labeled by the first letter of their names. [Source: David Koch; redrawn from Kasting, et al (1993).]

Plotting the Exoplanet

Locate where this exoplanet would appear on this graph. (Click on graph to view a larger version that can be printed. Then place an "x" where the present exoplanet should be plotted.) Note that both the horizontal and vertical axes are logarithmic. For example, the tick marks along the vertical axis go in this order: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7. 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20 and 30.

Where is the present exoplanet located?

 The exoplanet is definitely in the habitable zone on the graph. The exoplanet is definitely not in of the babitable zone onthe graph. The exoplanet is near the border between the habitable zone and the non-habitable region.

Press the "Next Page" button to continue your analysis.

### Explanations

Notes on Habitable Planets

• The definition of habitable raises many questions since the only habitable planet that we are acquainted with is the Earth. However, scientists have suggested some basic criteria. For example:
• A habitable planet should have liquid water on or near its its surface. This stipulates a narrow temperature range for the surface of the planet.
• Habitable planets should probably have hard crusty surfaces, that is, to be Earth-like or terrestrial, and not gaseous giants. Thus the planet's average density should be close to that of Earth.

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