I'm given this set of data and I need to describe the habitability. Would this not be habitable since the temperature of the albedo and the equilibrium is similar to Earth's or does the Spectral Type M affect the planet that much?

  • Spectral Type: M

  • Age of the Star (Gyr): 0.664

  • Binary System: Single Star

  • Planet Orbital Period (Years): 0.0387

  • Planet Semi-Major Axis (AU): 0.0613

  • Planet Mass (Earth Masses): 1.87

  • Planet Radius (Earth Radii): 1.24

  • Method of First Detection: Transit

  • Eccentricity: 0.11

  • Atmospheric Composition (Percent by Volume):

    N2 77.8
    CO2 0.00368
    H2O 2.37
    O2 19.8

  • Number of other (known) Planets in the System: 1

  • Location in the Galaxy: Open Cluster

  • Distance from Earth (lightyears): 960

  • Atmospheric Pressure (atm): 1

  • Stellar Mass (Solar Masses): 0.154

  • Planetary Albedo: 0.271

  • Planet Equilibrium Temperature (K): 243

  • Stellar Radius (Solar Radii): 0.171

  • Orbital Inclination (degrees): 5.7

  • Planet Axial Tilt (degrees): 18.4

  • Magnetic Field Strength (Units of Earth Magnetic Field): 0.109

  • 2
    $\begingroup$ This doesn't seem to be real data. It is a made up world. $\endgroup$ – James K Apr 1 '19 at 5:44
  • $\begingroup$ Your question looks unclear. Please fix it ASAP - a closure vote is going on. $\endgroup$ – peterh Apr 1 '19 at 6:06
  • $\begingroup$ Fried by UV and X-ray flares. $\endgroup$ – ProfRob Apr 1 '19 at 6:22
  • $\begingroup$ That high percentage of atmospheric oxygen is a bit suspicious, although I guess it could have been produced by UV photolysis of atmospheric water. $\endgroup$ – PM 2Ring Apr 1 '19 at 7:32
  • $\begingroup$ You should check out this preprint by Schweiterman et al. - even if they are habitable in the "supports liquid water" sense, planets around cooler red dwarfs are likely to build up lethal (to humans) levels of carbon monoxide. $\endgroup$ – user24157 Apr 1 '19 at 17:53

A very low mass M-dwarf (what you have there is something like an M5-M6 dwarf) will remain a highly magnetically active star for several billion years.

As such, the spectrum of light from such an object has a much higher proportion, by several orders of magnitude, of UV and X-ray emission than the Sun.

Therefore, if your planet is close enough to its star to receive a similar bolometric flux as the Earth does from the Sun, then it will get a very hefty dose of UV and X-rays. In addition to this, there will be flaring activity that raises these levels by more orders of magnitude for minutes or hours at a time.

There is not enough detail to know how well the planet is shielded from this, but it is unlikely to be habitable (by us).


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