Using K2 To Find Free-floating PlanetsNow with more microlensing!

Calen B. Henderson (JPL NPP Fellow)K2C9 Microlensing Science Team Member

K2 Science ConferenceTu, 3/Nov/2015

Credit: NASA

Exoplanet Demographics

Adapted from:Spergel+ (2015) arXiv:1503.03757

Single Object Lensing Light Curve[Free-floating Planet (FFP) Candidate]

Sumi+ (2011) Nature, 473, 349

Single Object Lensing Light Curve[Free-floating Planet (FFP) Candidate]

Sumi+ (2011) Nature, 473, 349

tE

Sumi+ (2011) Nature, 473, 349

Putative FFP Population

Putative FFP Population

~700 MEarth

per star!!

Sumi+ (2011) Nature, 473, 349

1: Bowler+ (2015) ApJS, 216, 7

2: Clanton & Gaudi (2014) ApJ, 791, 91 // 3: Fressin+ (2013) ApJ, 766, 81

4: Sumi+ (2011) Nature, 473, 349

5: Pfyffer+ (2015) ApJ, 579, 37

tE = f(Dl,Ml,vrel)

Sumi+ (2011) Nature, 473, 349

Not so Fast: From Short tE to FFP

Yee+ (2015) ApJ, 802, 76

Satellite Parallax I: Spitzer

Credit: NASA/JPL-Caltech

Credit: Krzysztof Ulaczyk

Yee+ (2015) ApJ, 802, 76

Satellite Parallax I: Spitzer

Credit: NASA/JPL-Caltech

Credit: Krzysztof Ulaczyk

πE helps determine (Ml, Dl)

Satellite Parallax II: K2 Campaign 9

7/April 1/July, 2016

~4 square-degrees

πE for ~few hundred events

Campaign Details

Satellite Parallax II: K2 Campaign 9

Courtesy of Matthew Penny

Batista+ (2014) ApJ, 780, 54

Vetting FFP Candidates in the NIR

Batista+ (2014) ApJ, 780, 54

Vetting FFP Candidates in the NIR

Procedure Hs from ground-based

light curve data

Hl+s from AO follow-up

Arithmetic!

Search for excess flux

CTIO 1.3m: ANDICAM

Credit: CBH

CTIO 1.3m: ANDICAM

Credit: CBH

Keck: NIRC2

Credit: Ethan Tweedle Photography

CTIO 1.3m: ANDICAM

Credit: CBH

Keck: NIRC2

Credit: Ethan Tweedle Photography

Courtesy of Matthew Penny

Summary MOA survey discovery of excess of short-timescale microlensing events

FFP candidates!!

Tension between observation and theory Dominate mass budget of planet formation Not accounted for by dynamical ejection

K2C9 can measure masses and distances to FFP candidates!

NIR observations necessary:1) During event to get NIR source flux2) High-resolution follow-up, to search for possible host star

Bonus Features

Johnson+ (2010) PASP, 122, 905

Clanton & Gaudi (2014) ApJ, 791, 91

Bowler+ (2015) ApJS, 216, 7

Credit: NASA/JPL-Caltech