A Dedicated Search for Transiting Extrasolar Planets using a Doppler Survey and Photometric Follow-up A Proposal for NASA's Research Opportunities in Space Science Eric Nielsen April 28, 2004

Outline ● Extrasolar Planet Background ● Importance of Transits ● Program Basics ● Program Methodology

Radial Velocity Planet Searches ● 111 extrasolar planets found to date by Doppler surveys ● 25 of these planets are Hot Jupiters (P < 30 days) ● Requires chromospherically stable stars with spectral type F, G, K, or M for high radial velocity precision ● Frequency of RV planets increases with parent star's metallicity ● Only one confirmed transit from radial velocity surveys: HD b

Importance of Transits I ● Current RV surveys only give orbital parameters and M*sin(i) of exoplanets ● Transits give radius and more solid constraints on the mass of the planet ● Transits also give the opportunity of obtaining spectra of the planet exoplanets.org

Importance of Transits II ● Transits are the only available method for taking spectra of exoplanets ● Determine composition of atmospheres ● Constrain models of Hot Jupiter formation and structure Richardson et al. 2003

Going beyond current RV surveys ● No significant number of additional hot Jupiter expected to be detected by current surveys ● 3 m/s precision is overkill for such large reflex motions exoplanets.org

Photometric Confirmation of Transits ● Detection of transits requires ~1 % photometry ● Follow up Hot Jupiter detections with: – amateur astronomy equipment – under-subscribed “small” telescopes Brown et al Seagroves et al. 2003

Program Outline I ● Observing time per year – Keck 10m 8 nights – VLT 8.4m 12 nights – AAT 3.8m 15 nights – Lick 3m 12 nights ● Survey will include 1100 stars – Spectral types F, G, and K – High metallicity sample: [Fe/H] > 0

Program Outline II ● Focus on Hot Jupiters – Drop required S/N to velocity precision of 10 m/s, allows inclusion of currently unsampled stars – Star is dropped from the program if no RV signature is found after 5 observations ● Expected results – 165 stars should have RV planets – 41 Hot Jupiters to be detected over 3 years – 2 Transits – Triples the number of known transits from RV targets.

Planets Correlate with Metallicity Fischer et al. 2004

OGLE Detections ● OGLE's detection of transits is sensitive mainly to periods P < 10 days, while our program will seek planets out to P < 30 days ● The stars surveyed by OGLE are ~5 magnitudes fainter than those in our survey, leading to radial velocity errors of 100 m/s – only the closest-in planets are confirmable with RV follow-up ● The 100x factor in flux severely limits the quality of the spectra that can be extracted during transits

Gratuitous 55 Cancri reference exoplanets.or g