Opportunities for amateurs

I struggle to see how you come to that conclusion, Roger.

On the ground, professionals have NGTS, WASP, HAT, KELT, not the mention several smaller exoplanet search programs. In space, professionals have TESS, soon to be joined by CHEOPS, and later PLATO. Right now, professional exoplanet search programmes are incredibly active, and will remain so for at least the next decade. Probably far beyond.

There’s relatively little professional effort going into biosignatures, because it’s basically impossible to detect them with current technology. Yes, people have pointed large telescopes (e.g. the VLT) with high-resolution spectrographs at bright stars, and picked up spectral lines in exoplanet atmospheres (NB: abundant things like water, not “biosignatures”). It’s impressive work, but only possible for a handful of the brightest stars, orbited by very large planets. When the ELT comes online in 2024, it will be possible for more stars, but we’ll still be talking about molecules like water and methane in the atmospheres of small numbers of giant planets.

I’m puzzled by this talk of amateur opportunities for the “discovery of exoplanets”. The best amateurs can achieve right now is to observe predicted deep transits, if they squint really hard at their photometry. That’s already very difficult, and far short of actually discovering a transit you didn’t already know about. Perhaps you’ll prove me wrong, but I’d consider my money pretty safe if I bet that there will be no amateur exoplanet discoveries in the next decade. Unless you plan to build a replica of the NGTS in your back garden…

Yes, I agree that amateur transit surveys are tantalisingly within reach. The hardware used by most of the ground-based professional surveys is basically high-end amateur kit. Though, crucially, with professional-grade CCDs, dark sites, and many years of software development to pull out ridiculously small signals from the photometry.

I am doubtful about the prospects for amateurs discovering even hot Jupiters by themselves. The professionals have been at this game for a couple of decades now, and I suspect all the really conspicuous transiting objects have already been found. There are bound to be plenty remaining with long periods, but amateurs will have the same difficulty as professionals that you’re unlikely to happen to be looking at the right star at the right time to record very infrequent transits (bearing in mind you have to see at least 2-3 transits of the same planet to convince anyone).

Doing follow-up on known targets sounds like a far more realistic prospect.

Though, of course, I invite you to prove my scepticism wrong! 🙂

I’m of the opinion that single small telescope, weather limited transit searches such as those that can be run from the UK will struggle to make headway.  In part this is because the large scale survey projects, especially space based ones like TESS, are quickly hoovering up all the low hanging fruit that is likely detectable with amateur equipment but also because there are already so many transiting Exoplanets now that the professional observatories have a hard time following them up and undertaking long term monitoring, creating an ideal niche for amateurs to fill.  There is a lot of good science to be had from observations of already known systems.

All that said, there are many viable alternative approaches for getting involved in new Exoplanet discoveries, all of which stand the best chance when working as part of a widely (global) dispersed pro-am team.  The first is candidate winnowing where you increase your chance of success by observing targets already suspected to host transiting Exoplanets.  Another is by observing known transiting systems on the basis that if there is one transiting planet already then you know the system is preferentially aligned, increasing the chance of discovering additional planets.  A third approach is via transit timing variations (TTV’s) when the transit times are measured precisely enough to detect the effect of (unseen) companions as they interact gravitationally with the transiting planet.  This is one of the most powerful techniques in Exoplanet observing, used extensively in the Kepler data set and which has already led to discoveries from small telescope observations e.g. https://arxiv.org/abs/1806.03503.  There is one final approach which is to undertake searches using  publicly available survey data, which doesn’t even require a telescope.

I guess what I’m trying to say is that there’s many ways to get involved in one of the fastest moving and most exciting areas of astronomy (in my unashamedly biased view).

Robin, thanks for pointing out that paper I missed it.

Stan Waterman’s survey was one I had been thinking of and I had been in touch with him last year.  He has many folded light curves including minima of many new variables, including eclipsing binaries.  The problem is following up to determine a period and ephemeris.  There are a couple of his objects I’m particularly interested in with regard to exoplanets.

Eric

A few months ago I discovered an EA variable in images taken by Kevin Hills where the primary minimum is around 25 mmag and the secondary is about 10 mmag.  Not an exoplanet discovery in this case but well within the range of variability resulting from exoplanet transits, which tend to lie between 5 and 30 mmag.

I’m with Roger on this one.

Added in edit: I should analyse the rest of Kevin’s data to see what else turns up.