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First Evidence of Extrasolar Planets Discovered In 1917

Posted by Soulskill on from the but-who's-counting dept.

KentuckyFC writes: Earth's closest white dwarf is called van Maanen 2 and sits 14 light-years from here. It was discovered by the Dutch astronomer Adriaan van Maanen in 1917, but it was initially hard to classify. That's because its spectra contains lots of heavy elements alongside hydrogen and helium, the usual components of a white dwarf photosphere. In recent years, astronomers have discovered many white dwarfs with similar spectra and shown that the heavy elements come from asteroids raining down onto the surface of the stars. It turns out that all these white dwarfs are orbited by a large planet and an asteroid belt. As the planet orbits, it perturbs the rocky belt, causing asteroids to collide and spiral in toward their parent star. This process is so common that astronomers now use the heavy element spectra as a marker for the presence of extrasolar planets. A re-analysis of van Maanen's work shows that, in hindsight, he was the first to discover the tell-tale signature of extrasolar planets almost a century ago.

7 of 58 comments (clear)

  1. Roundabout by Tablizer · · Score: 2

    That's rather indirect evidence. The title is a bit misleading if you ask me. It's an interesting fact, I agree, but the title needs work.

    --
    Table-ized A.I.
  2. Actually... by Thanshin · · Score: 4, Insightful

    So now the first discoverer is the one who sees it for the first time even if that person doesn't know what it was that he saw? Great! I might be the discoverer of a distant supernova if I'm the first human being whose eye is hit by a photon created during it's explosion!

    Now to play the waiting game until someone discovers it. Oh, no, I mean until someone correctly identifies it as a supernova and someone else points out that I am the discoverer, because the photon hit me first.

    1. Re:Actually... by rossdee · · Score: 2

      "As far as I know we still accept Columbus as the discoverer of America"

      No we don't.

      I was taught in school that Lief Ericson did.

    2. Re:Actually... by Anonymous Coward · · Score: 3, Interesting

      Indeed, so some criteria are needed to established who is the discoverer. As far as I know, one of those criteria is knowing what's being discovered.

      At what point would you say that one "knew" what America was. We know that Columbus didn't know it. Was it when the west coast was discovered, or would one have to find both Alaska and the southern tip of Chile as well?
      Perhaps we can conclude that America has yet to be discovered?

  3. Sirius B! by Anonymous Coward · · Score: 5, Informative

    "Earth's closest white dwarf is called van Maanen 2 and sits 14 light-years from here." Balderdash! Sirius B is a white dwarf that 7 years from here.

  4. Data, not evidence by Required+Snark · · Score: 4, Insightful
    Evidence is the loaded term here. It's only evidence in the context of a hypothesis, otherwise it is an observation, i.e. data.

    The Hertzsprung–Russell diagram was proposed in 1910. It wasn't until the 1930's that it was understood how fusion was the energy producing mechanism for stars. Without understanding fusion and stellar evolution, there was no context in which to fit the observation of enhanced metallic elements in the star's spectrum.

    So this only became evidence decades after the initial observation. It's interesting that the observation was made so early, but only retrospect makes it significant.

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    Why is Snark Required?
  5. Re:The closest? by Teresita · · Score: 2

    Van Maanen's star is the closest white dwarf that's all by its lonesome, that's what the article meant.