Telescope Proposal

Hey everyone,

Yesterday myself, Meg, Chris and the rest of the Planet Hunters team where working hard to get us to the next stage of discovery with Planet Hunters. As you all know we have been really successful at finding interesting objects that the Kepler team’s automated algorithm has missed. Our first trawl through the data has netted us lots of potential planet discoveries. While this is great we really want to remove the potential from the sentence! So yesterday the team submitted a proposal to to the Keck telescope to request time to follow up the results from the site.


The Keck telescope is a wonderful instrument located 4,145 metres up, near the summit of Mauna Kea in Hawai’i. Composed of two telescopes each with a mirror 10 metres across, it is one of the best astronomical instruments in existence.

Unfortunately this means Keck, like most modern telescopes, is large, complex and therefore expensive. It cant be run by any one team or even any one country. It might be many times larger than your telescope at home but at least you get to look through that telescope whenever you want, while astronomers have to share time on Keck. Infact share is even stretching it a little, what actually happens is astronomers compete each year for time on the telescope. Unfortunately this competition doesn’t involve some kind of X-Factor public voting system (otherwise we could get all you guys to rig it for us) but rather is decided by a board of scientists who run the Keck telescope. Each year they receive a lot of requests from scientists to use their magnificent instrument but there is only enough time for a limited number of observations. The science team for Keck will independently asses each request for scientific merit, practicality and interest to decide who gets those valuable hours gathering photons.

To make matters worse pretty much every telescope, on earth or in space, has this competition at the same time each year. This means that astronomers all over the world scramble to get their proposals in and astronomy departments are full of sleep-deprived, very stressed-out people. Meg, who did the lion’s share of the work for our proposal, also had another 2 due at the same time for different telescopes! She somehow managed to get them all in and I hope is even now sleeping to recover from her ordeal. Thanks, Meg!

We have asked them for two nights worth of observing time using the HIRES instrument on Keck. During this time we point the telescope at and take spectra of our top planet candidate hosts. This will let us do two things, learn more about the host stars themselves to lets us characterise the potential planets better, but more excitingly it will let us look for the telltale wobble of the host star. If we see this it would would give us independent confirmation what we are seeing is really an exo-planet! At that point we can bin that annoying “potential” prefix and say without fear of contradiction that you, the Zooites of Planet Hunters, have discovered a new world !

We are by no means guaranteed to get the time but we all have our fingers crossed and we will let you know as soon as we do.

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5 responses to “Telescope Proposal”

  1. robert gagliano says :

    1)How many spectra can you obtain for radial velocity determinations in 2 nights per month (assuming ideal observing conditions)with Hires/Keck compared to the number of “potential” exoplanet candidates that Planet Hunters has generated? 2)What criteria do you use to decide which “potential” exoplanet candidates are deserving and best suited for spectra? Thanks.

  2. Marilee says :

    Congratulations to Meg for getting the proposal(s) done! It would be amazing for everyone participating in the PlanetHunters project to see our candidates examined via the Keck telescope! Hopefully the science team making the decisions will see how important it is for the future development of Citizen Science projects to get take this project to the next logical step.

    Go team!

  3. Andres Eloy says :

    The telescope Keck will be tested in the candidate planets
    we have discovered planet hunters?

  4. Meg says :

    Robert – time on these large telescopes is highly coveted (I wish we could have two nights a month on Keck!) – we are asking for two nights for the observing semester when the Kepler field is observable – the decision for which ones we can target for radial velocity measurements depends on the brightness of the star, the estimated radii of the planet, and the orbital period and what kind of precision we need – so all those factors get considered together

    we’re going for resolution to first try and rule out stellar masses for the transiting companion. A faint background eclipsing binary system may be blended with the Kepler target star generating a false transit-like signal from the combined lightcurve. From radial velocity Doppler measurements, the mass (or rather Msini with inclination constraints from the transit observations) of the transiting companion can be measured. Follow up radial velocity measurements of the bright star will also include the background blended eclipsing binary and the radial velocity signal will be dominated by the faint eclipsing binary. These radial velocity measurements will eliminate stellar companions as the transiting object for our planet candidates and will also constrain the upper mass limit of the transiting body

    ~Meg

  5. Joe (constovich) says :

    Way to go, Meg! Here’s to hoping we get that time!

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