It's unlikely many types of exoplanets could have been detected "decades" earlier. Transit and Doppler detection methods require good seeing power and accurate intensity measurements. It takes large mirrors with good optics for good seeing power and sensitive electronics for the spectral/intensity measurements. Those two things weren't readily available until the past few decades...which surprise is when exoplanet discoveries started happening.

Hot Jupiters and CFCs are very different things. Hot Jupiters were puzzling but something that could be readily detected by existing instruments. Once discovered solar system development models were improved.

CFCs in a planet's atmosphere is something current instruments can't detect. Even if they could the number of observational candidates is limited. The only way we could detect CFCs is if some civilization was actively producing them at the time that light left the planet. So even if there's millions of CFC producing civilizations in the galaxy the odds of detecting those CFCs in candidate systems is extremely low. Even if those civilizations produced CFCs for millennia the odds are against ever seeing them. So it's pretty wasteful to use valuable telescope time for that rather than something that has a higher probability of giving some results.

It's not about solar system chauvinism or biases. There's not infinite amounts of science money or science time. No one is writing off unlikely events, it's just breathless searches for those unlikely events has a huge opportunity cost. And talking about biases, assuming technological civilizations will produce CFCs is a very Earth/Human biased assumption. CFCs were/are produced on Earth for market reasons that don't necessarily apply in any circumstances except those that worked out on Earth.

>> It's unlikely many types of exoplanets

Ya, but if people were allowed to look for hot jupiters in the 70s/80s they would have found the first exoplanet far sooner.

Allowed? No one was banned from looking for Hot Jupiters. They weren't an expected phenomenon. The instruments to detect them also didn't/barely exist in the 70s and 80s and they're some of the easiest exoplanets to detect.

Fun fact. Amateur astronomers can use photometry to detect some transiting exoplanets using as small as a 4'' telescope on a night with good seeing. Atmospheric composition is a different matter.

> Those two things weren't readily available until the past few decades...which surprise is when exoplanet discoveries started happening.

I think the other poster might be alluding to a chicken-and-egg situation: could a stronger theoretical basis for the existence of 'Hot Jupiters' have driven development toward the goal of their detection 20 years earlier?

Hot Jupiters were unknown until they were discovered once instruments were sensitive enough to detect them. No major planetary development models predicted them. The current best explanation for them is they formed much further out from their parent stars and migrated inward. The migration phenomena is still poorly understood, it wasn't on anyone's radar in the 70s and 80s.

So until Hot Jupiters were discovered they were not predicted. No one even thought to look for them. No one was thinking about Hot Jupiter detectors that just didn't get funding.

Had billions of dollars flowed into astronomy instead of particle accelerators exoplanets (of all types) might have been discovered earlier. Then again they may not have. It's a pointless "what if".