What I have established about this planet is that it is the size of Earth but it is located 2.2 AU from Barnard’s star, a red dwarf. I’m trying to figure out how much greenhouse gases are needed to keep the planet in an Earth-like temperature.

  • 1
    $\begingroup$ Such a planet would be an iceball. Even greenhouse gasses would be frozen. It would also need to be a captured planet. An accreted planet would still have most of its hydrogen due to the lack of stellar wind to blow it away. $\endgroup$ Jan 30, 2023 at 22:38
  • 2
    $\begingroup$ To get the best answers, you should limit yourself to one precise question. Here you ask about greenhouse gase-ing your planet + what the sky would look like (and how well you'd see). Pick the most important one for you, deal with the other in another question :). $\endgroup$ Jan 30, 2023 at 23:43
  • $\begingroup$ Could you give more specific information about this imaginary planet? "A planet" sounds extraordinarily vague. $\endgroup$
    – Joachim
    Jan 31, 2023 at 10:17
  • $\begingroup$ Hi, Joachim. I imagined the planet to be the same size as Earth, with a Mars-like composition. $\endgroup$ Jan 31, 2023 at 13:34
  • $\begingroup$ Bernard's star is a M4.0V star. According to the table in the answer by User 17707 to this question astronomy.stackexchange.com/questions/40746/…, the Earth Equivalent Distance or EED where a planet receives the same amount of radiation as Earth gets from the Sun would be 0.163 AU for a M2V star and 0.0547 AU for a M5V star. Continued. $\endgroup$ Jan 31, 2023 at 18:32


You must log in to answer this question.

Browse other questions tagged .