OGLE-2003-BLG-235/MOA-2003-BLG-53: A Definitive Planetary Microlensing Event

1. OGLE-2003-BLG-235/MOA-2003-BLG-53: A Definitive Planetary Microlensing Event David Bennett University of Notre Dame

2. Author List: I.A. Bond, A. Udalski, M. Jaroszynski, N.J. Rattenbury, B. Paczynski, I. Soszynski, L. Wyrzykowski, M.K. Szymanski, M. Kubiak, O. Szewczyk, K. Zebrun, G. Pietrzynski, F.Abe, D.P. Bennett, S. Eguchi, Y. Furuta, J.B. Hearnshaw, K. Kamiya, P.M. Kilmartin, Y. Kurata, K. Masuda, Y. Matsubara, Y. Muraki, S. Noda, K. Okajima, T. Sako, T. Sekiguchi, D.J. Sullivan, T. Sumi, P.J. Tristram, T. Yanagisawa, and P.C.M. Yock (the MOA and OGLE collaborations)

3. Real-Time Lightcurve Monitoring is Critical! • Ian Bond (IFA, Edinburgh) noticed a caustic crossing for this event on July 23, 2003. • He contacted the telescope and requested additional images • The requested images caught the caustic crossing endpoint. • This caustic endpoint data is critical to the conclusion that a planet is required.

4. Lightcurve OGLE alert

5. Definition of a Planet • Formed by core accretion? (with a rocky core) • But we don’t know that this is how planets form! • We aren’t even sure about Jupiter’s rocky core! • Secondary Mass < 13 Mjupiter? • This is the Deuterium burning threshold for solar metalicity, but why is that important? • What if binary is a 0.08 M? • Mass ratio may only be 0.16! • In the brown dwarf desert • Planetary mass fraction  < 0.03 • In the brown dwarf desert • Easily measured in a microlensing lightcurve!!

6. Lightcurve close-up & fit • Cyan curve is the best fit single lens model • 2 = 651 • Magenta curve is the best fit model w/ mass fraction   0.03 • 2 = 323 • 7 days inside caustic = 0.12 tE • Long for a planet, • but mag = only 20-25% • as expected for a planet near the Einstein Ring

7. Caustic Structure & Magnification Pattern Blue and red dots indicate times of observations Parameters: tE = 61.6  1.8 days t0= 2848.06  0.13 MJD umin = 0.133  0.003 ap = 1.120  0.007  = 0.0039  0.007 q = /(1+ )  = 223.8  1.4 t*= 0.059  0.007 days or */E = 0.00096  0.00011

8. Alternative Models: ap < 1 2 = 110.4 tE = 75.3 days t0= 2850.64 MJD umin = 0.098 ap = 0.926  = 0.0117  = -6.1 t*= 0.036 days Also planetary!

9. Alternative Models: ap < 1 2 = 110.4 tE = 75.3 days t0= 2850.64 MJD umin = 0.098 ap = 0.926  = 0.0117  = -6.1 t*= 0.036 days Also planetary!

10. Alternative Models:  ~180 2 = 40.15 tE = 76.0 days t0= 2847.09 MJD umin = 0.100 ap = 1.064  = 0.0127  = 185.6 t*= 0.034 days Also planetary!

11. Alternative Models:  ~180 2 = 40.15 tE = 76.0 days t0= 2847.09 MJD umin = 0.100 ap = 1.064  = 0.0127  = 185.6 t*= 0.034 days Also planetary!

12. Alternative Models: Early 1st Caustic Crossing 2 = 7.37 tE = 58.5 days t0= 2847.90 MJD umin = 0.140 ap = 1.121  = 0.0069  = 218.9 t*= 0.061 days Excluded by 2.7 Adjust  = 0.0039  0.007 to  = 0.0039  0.011

13. Lens Star Constraints Using Isource = 19.7 and V-I = 1.58,we conclude that the source is a bulge G dwarf of radius: * = 520  80 as Iblend= 20.7  0.4 Gives likelihood curve

14. Planetary Parameters in Physical Units • Best fit lens distance = 5.2 kpc • 90% c.l. range is 2.3-5.4 kpc • Best fit separation = 3.0 AU • 90% c.l. range is 1.3-3.1 AU • Best fit stellar mass = 0.36 M • 90% c.l. range is 0.08-0.39 M • Best fit planet mass = 1.5 Mjup • 90% c.l. range is 0.3-1.6 Mjup • If lens star is a 0.6 M white dwarf • Dlens = 6.1 kpc • ap = 1.8 AU • Mp = 2.5 Mjup

15. Conclusions 1st definitive lensing planetary discovery - complete coverage not required for characterization Real-time data monitoring was critical! S. Gaudi video