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Ringing in the New Year

January 2nd, 2009

Landscape photographed on HD 40307e

The “top ten” list provides a perennially easy vehicle for writing an end-of-the-year web log post. “Top three” lists, because they’re shorter, are even easier to write. In the interest of maintaining a near-weekly posting schedule, here’s my short-short list of the biggest exoplanet-related stories for 2008.

1. A raft of super-Earths and sub-Neptunes. The biggest news from 2008 was the announcement by the Geneva group that 30% of solar-type stars harbor Neptune or lower mass planets with orbital periods of 50 days or less. This discovery has far-reaching implications for ongoing planet detection efforts, and was completely unexpected by theorists. In short, a big deal.

2. HR 8799 b, c, and d. The discovery of massive planets via direct imaging was the marquee event of 2008 for the broader media. Stars more massive than the Sun seem to be uncannily effective at forming planets — it’s thus a good bet that more direct imaging detections will be coming on line shortly.

3. Radial Velocity holds its own. The S&P 500 may have been down almost 40% in 2008, but the detection rate for extrasolar planets held steady, with exoplanet.eu reporting 62 credible announcements. I had thought 2008 would be the year that the transit method pulled ahead, but the Doppler technique (turbo-charged by the populations of sub-Neptunes and giant planets orbiting giant stars) had a banner second half, logging 32 new worlds. Nonetheless, direct imaging and microlensing are really starting to produce, logging five planets and four planets respectively.

And looking forward? It’s always risky to make predictions, but here’s what I think we’ll have in hand by the end of 2009:

1. A 1.75 Earth Mass planet orbiting a Main Sequence star.

2. A confirmed case of transit timing variations.

3. A transiting planet in a well-characterized multiple-planet system.

4. A transiting super-Earth (or more precisely, on the basis of observed composition, a transiting sup-Neptune).

5. 417 planets listed on exoplanet.eu.

It would be cool if 1 through 4 were all part of the same story, but we probably won’t be quite that lucky.

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  1. Hungry4info2
    January 3rd, 2009 at 07:44 | #1

    The two planets discovered at HW Vir may constitute the first confirmed case of transit timing variations.

    What are the odds that one of those first four (or 3?) is the answer to the anagram?

  2. January 3rd, 2009 at 12:46 | #2

    There are some interesting hints of transit variations in some systems. I take it nothing ever came of the possible second transiting planet at OGLE-TR-111.

  3. Hungry4info2
    January 3rd, 2009 at 17:45 | #3

    The most recent paper about transit timing variations at OGLE-TR-111 is this one,
    http://fr.arxiv.org/abs/0806.1229
    Which mentions that eccentricity of the planet may still explain the TTV’s, and is not ruled out by available radial velocity data.

  4. January 4th, 2009 at 12:51 | #4

    Also, interesting image title…

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