Thread by @Astro_Wright

A hearty congratulations to Michel Mayor & Didier Queloz, for kickstarting the field that I've built my career in! Their discovery of 51 Peg b happened in my senior year of high school, and I started working in exoplanets in 2000, when ~20 were known.

A thread:

The Nobels serve a funny place in science: they are wonderful public outreach tools, and a chance for us all to reflect on the discoveries that shape science. The discussions they engender are, IMO, priceless.

They also have their flaws: because they are only be awarded to 3 at a time, they inevitably celebrate the people instead of the discovery.

(This technically a requirement from Alfred Nobel's will, but there are other requirements, like that the discovery be in the past year, that the committee ignores.) Also, the Peace Prize is regularly awarded to teams, but the science prizes have never followed suit.

Anyway, many of the discoveries awarded Nobels are from those who saw farther because they "stood on the shoulders of giants." The "pre-history" of exoplanets is a hobby of mine, so below is a thread explaining the caveats to 51 Peg b being the "first" exoplanet discovered.

The first exoplanet discovered was HD 114762b by David Latham et al. (where "al." includes Mayor!) in 1989. It is a super-Jupiter orbiting a late F dwarf (so, a "sun like star" for my money), published in Nature:
nature.com/articles/33903…

Dave is a conservative and careful scientist. At the time there were no known exoplanets *or* brown dwarfs, and they only knew the *minimum* mass of the object, so there was a *tiny* chance it could have been a star. He hedged in the title, calling it "a probable brown dwarf".

I wonder: if Dave had been more cavalier and declared it a planet, would *that* have kickstarted the exoplanet revolution? Would he be going to Oslo in a few months?

Meanwhile, Gordon Walker, Bruce Campbell, and Stephenson Yang were using a hydrogen fluoride cell to calibrate their spectrograph. In 1988 they published the detection of gamma Cephei Ab, a giant planet around a red giant star:
ui.adsabs.harvard.edu/abs/1988ApJ...…

They were also very careful. Six other signals reported there turned out to be spurious. They did not claim they had discovered any planets, just noted the intriguing signals. In follow up papers they decided the gamma Cep signal was spurious. Turns out it was actually correct!

Again, what if they had trumpeted these weak signals and parlayed that into more funding to continue their work? Would they have confirmed them and moved on to dwarf stars? Would they be headed to Stockholm?

*I wrote Oslo a few tweets up, but that's where the *peace* prize is awarded. The science prizes are awarded in Stockholm.

Moving on: in 1993 Artie Hatzes and Bill Cochran announced a signal indicative of a giant planet around the giant star beta Gem (aka Pollux, one of the twin stars in Gemini).

Like gamma Cep A, the signal was weak. Like Campbell Walker & Yang, they hedged about its reality. But again, it turns out it's real!
ui.adsabs.harvard.edu/abs/1993ApJ...…
ui.adsabs.harvard.edu/abs/2012A%26A.…

Then, in 1992 Matthew Bailes and Andrew Lyne announced they had discovered an 10 Earth-mass planet around a *pulsar*. This was big news! Totally unexpected! What was going on! They planned to discuss in more detail in a talk at the AAS that January.

But when the big moment came, Bailes retracted: they had made a mistake in their calculation of the Earth's motion. There was no planet, after all. That made more sense. He got a standing ovation for his candor.

But in the VERY NEXT TALK Alex Wolszczan got up and announced that he and Dale Frail had discovered *two* Earth-massed planets around a different pulsar! They would later announce a third, and that remains the lowest mass planet known.
ui.adsabs.harvard.edu/abs/1992Natur.…

The previous retraction took some of the wind out of their sails, though. Was this one really right? Had they done their barycentric correction properly?

This one held up. The first rocky exoplanets ever discovered, and the last to be discovered for *20 years*.

Meanwhile, in a famous "near miss", Marcy & Butler were slogging through their iodine work. They actually had the data of multiple exoplanets on disk when Mayor & Queloz announced 51 Peg b, but not the computing power to analyze it.

If you're interested in more detail, you can read this "pre-history" in section 4 of my review article with Scott Gaudi here:
arxiv.org/abs/1210.2471

None of this, BTW, is meant to detract from Michel & Didier's big day. As I wrote above, they kickstarted the exoplanet revolution, and deserve the prize.

This is to make sure that the Nobel serves its best purpose: educating, and promoting and celebrating scientific discovery.

I missed one! Somehow I did not realize that @steinly0 had published an interpretation of the PSR 1620-12 binary period changes as due to a planet in 1993!
ui.adsabs.harvard.edu/abs/1993ApJ...…

From the abstract: "The anomalous spin period second derivative of the binary millisecond pulsar PSR 1620-26 in the globular cluster M4 is best explained by a sub-Jovian mass planet"

So add one more planet to the pre-history list!

Also: 51 Peg b was the first exoplanet with the right combination of minimum mass, strength of detection, and host star characteristics to electrify the entire astronomy community and mark the exoplanet epoch. It makes sense that Mayor & Queloz got the prize!

Now I'm even more embarrassed I had missed this one in my discussion of pre-1995 exoplanets in my review article with @bsgaudi—Don Backer (who taught me graduate E&M) published it in Nature in 1993!
ui.adsabs.harvard.edu/abs/1993Natur.…