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Distance of GJ 436b to GJ 436 - doesn't work out.

  1. Jun 24, 2015 #1
    In an article on phys.org [http://phys.org/news/2015-06-red-dwarf-planet-hydrogen-massive.html] [Broken], it states that the exoplanet GJ 436b is 33x closer to its parent star than the earth is to our sun. It also states that the exoplanet is less than 2 million miles away from the star. If I assume an average distance of 93 million miles (earth-sun), then 1/33rd that yields nearly 3 million miles. Less than 2 million miles would yield a value approximately 48x closer than the earth-sun distance. What am I assuming incorrectly?
     
    Last edited by a moderator: May 7, 2017
  2. jcsd
  3. Jun 25, 2015 #2

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    You are assuming the article is correct. That phys.org article is a word-for-word copy of http://www.nasa.gov/feature/goddard...h-bleeding-atmosphere-around-a-warm-exoplanet .

    When you look at other sites, and even better, in scientific journals (e.g., http://arxiv.org/abs/0707.2778), GJ 436b's orbit has a semi-major axis of 0.0291 au, or 2.7 million miles. The easiest explanation is that there's a typo in the NASA press release, and that this typo was copied over and over without question by sites such as phys.org.
     
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