The Carnegie Astrometric Planet Search and the role of ground based astrometry in the pre-Gaia era. Guillem Anglada-Escude (1,2) Alan P. Boss(1) Alycia Weinberger (1) Ian Thompson (1) (1)Carnegie Institution for Science (2) Institute for Astrophysics - University of Goettingen

Astrometry and radial velocity methods K Time RV 

1º 3474 km 1’ 120 km 1/60 1’’ 2 km 1/ m 1 mas 2 cm 10  as 1/100 1  as A closer look at astrometry…

Astrometric recipes Exo-Jupiter formula Exo-Earth formula G 10 pc M 10 pc 0.1 mas 1.0 mas Man on the moon Book on the moon 3  as0.3  as Paper width on the moon Euro width on the moon Gaia/ESAGround based

Ground based Astrometry Why M dwarfs? Numerous Faint Low mass Poorly characterized Hosts to habitable planets (that can be detected)

Alan Boss (PI, DTM/CIW) Alycia Weinberger (DTM/CIW) Ian Thompson (OCIW) Chistoph Brik (OCIW) Greg Burley (OCIW) 2.5m duPont Telescope. Las Campanas Observatory, Chile Follow-up a sample of 120 M, L and T dwarfs Carnegie Astrometric planet Search

CAPScam (I band), 2048x2048

Classic local astrometry Input catalog Extract, centroid and crossmatch the sources Fit field distortions Shift (2 par) rotation, scale (4 par) Quadratic deformations (6 para) Obtain a new catalog Iterate

CAPS pipeline : ATPa software If you are interested in testing with your own images, please check Fully coded in Java (run on your computer) Graphic User Interface One night processing and Astrometric Iterative solution Final Data products : catalog, maps of extracted sources, reference stars, motion of each star, etc. It also has a Manual!

Carnegie Astrometric Planet search : Lots of parallaxes of cool dwarfs 200+ new and updated parallaxes

Carnegie Astrometric Planet Search program so far… Astrometric detection needs long time baselines (5-10 yr) Overall precision better than 1 mas/epoch. Almost 4 years of baseline, Gas giants should be detected soon (if present) About 120 M dwarfs

Carnegie Astrometric Planet Search… candidates? brown dwarfs gas giant planets 0.25 milliarcsec accuracy, S/N = HZ 0.5 HZ

GJ 317 GJ 1214 VB 10 Astrometric detection Pravdo & Shaklan 2010 ApJ P=270 days M ~ 6 M jup D = 7 pc Galactic plane Doppler candidate Johnson et al 2007, ApJ P=690 days M sin i ~ 2 M jup D = 9.6 pc [Fe/H] = -0.3?? Transit + Doppler planet Charbonneau et al. 2009, Nat P=1.83 days M sin i ~ 6 M eartj D = 12.0 pc Radius 15% larger?? Lessons learned from individual targets ???

Lessons learned from individual targets : VB 10 Black & Scargle 1982 Astrometry 2 x offsets 2 x Proper motions 1 x Parallax HD Fischer et al Doppler 1xoffset GJ 317, Anglada-Escude et al. 2012

Lessons learned from individual targets : VB 10 Pravdo & Shaklan ApJ, 2009 Residual periodograms Astrometric periodograms K = 1500 m/sK = 3000 m/s Anglada-Escude et al. ApJ, 2011

Anglada-Escude et al. ApJ 2011, RV follow-up with MIKE/Magellan Bean et al. 2011, RV follow-up with CRIRES/VLT Lazorenko et al. 2011, Astrometric follow-up Lessons learned from individual targets : VB days 270 days

Lessons learned from individual targets GJ 317 GJ 1214 VB 10 Astrometric detection Pravdo & Shaklan 2010 ApJ P=270 days M ~ 6 M jup D = 7 pc Galactic plane Doppler candidate Johnson et al 2007, ApJ P=690 days M sin i ~ 2 M jup D = 9.6 pc [Fe/H] = -0.3?? Transit + Doppler planet Charbonneau et al. 2009, Nat P=1.83 days M sin i ~ 6 M eartj D = 12.0 pc Radius 15% larger?? Astrometric periodograms (need better understanding of sampling)

d = 9.6 pc M * = 0.24 M sun M sin i = 1.85 M jup P = 692 days, a = 0.95 AU Exo-Jupiter formula 0.78 mas Jonhson, Butler et al. ApJ 2007 Lessons learned from individual targets : GJ 317

d = 14.9 pc 0.32 mas M * = 0.42 M sun M sin i = 1.8 M jup P = 692 days a = 0.95 AU d = 9.6 pc  =0.78 mas Lessons learned from individual targets : GJ 317

Likelihood function Period Mass Lessons learned from individual targets : GJ 317

Likelihood function Period Mass Provides optimal sampling in highly dimensional spaces N = 13 Run a few million steps and you are done! Lessons learned from individual targets : GJ 317

First exoplanet “confirmed” with Ground based astrometry! Lessons learned from individual targets : GJ 317

Lessons learned from individual targets GJ 317 GJ 1214 Doppler candidate Johnson et al 2007, ApJ P=690 days M sin i ~ 2 M jup D = 9.6 pc [Fe/H] = -0.3?? Transit + Doppler planet Charbonneau et al. 2009, Nat P=1.83 days M sin i ~ 6 M eartj D = 12.0 pc Radius 15% larger?? VB 10 Astrometric detection Pravdo & Shaklan 2010 ApJ P=270 days M ~ 6 M jup D = 7 pc Galactic plane Astrometric periodograms (need better understanding of sampling)

Lessons learned from individual targets GJ 317 GJ 1214 VB 10 Astrometric detection Pravdo & Shaklan 2010 ApJ P=270 days M ~ 6 M jup D = 7 pc Galactic plane Doppler candidate Johnson et al 2007, ApJ P=690 days M sin i ~ 2 M jup D = 9.6 pc [Fe/H] = -0.3?? Transit + Doppler planet Charbonneau et al. 2009, Nat P=1.83 days M sin i ~ 6 M eartj D = 12.0 pc Radius 15% larger?? Combine RV+Astrometry Astrometric periodograms (need better understanding of sampling)

Lessons learned from individual targets : GJ 1214 CAPS Astrometry (new) RMS < 1.0 mas HARPS-TERRA RVs (updated) 30 transit times and updated Transit observables Sada et al, 2010, Carter et al. 2011, Kundurthy et al., 2011 K band, low res(new) 4 Optical bands 3x2MASS bands 4xWISE bands (new)

Lessons learned from individual targets : GJ 1214 d M * L * T eff (0.14) pc (0.009) Ms L s 3200 K 12.9 (1.0) pc M s L s 2900 K +12% +13% +19% +10% Previous NEW!

Lessons learned from individual targets : GJ 1214

Lessons learned from individual targets GJ 317 GJ 1214 VB 10 Astrometric detection Pravdo & Shaklan 2010 ApJ P=270 days M ~ 6 M jup D = 7 pc Galactic plane Doppler candidate Johnson et al 2007, ApJ P=690 days M sin i ~ 2 M jup D = 9.6 pc [Fe/H] = -0.3?? Transit + Doppler planet Charbonneau et al. 2009, Nat P=1.83 days M sin i ~ 6 M eartj D = 12.0 pc Radius 15% larger?? Combine RV+Astrometry Astrometric periodograms (need better understanding of sampling)

Lessons learned from individual targets GJ 317 GJ 1214 VB 10 Astrometric detection Pravdo & Shaklan 2010 ApJ P=270 days M ~ 6 M jup D = 7 pc Galactic plane Doppler candidate Johnson et al 2007, ApJ P=690 days M sin i ~ 2 M jup D = 9.6 pc [Fe/H] = -0.3?? Transit + Doppler planet Charbonneau et al. 2009, Nat P=1.85 days M sin i ~ 6 M eartj D = 14.5 pc Everything is good! Combine RV+Astrometry Transits+RV, astrometry Simultaneous FIT! Astrometric periodograms (need better understanding of sampling)

‘Other’ exoplanet related programs… 10 years before Gaia Young field M dwarfs (UV and X ray sources) from Shkolnik et al ApJ 12 New members to nearby young moving groups (Beta Pictoris 10 Myr, AB Dor 40 Myr) 61 new parallaxes! Shkonlik, Anglada-Escude, Weinberger, Boss et al (to be submitted!) Based on astrometry obtained with ATPa (just accepted for publication, ApJ) J. O’Faherty PhD. Thesis

Early L brown dwarf at 12 pc

Synergies? The obvious… Combine with ground based observations Targeted follow-up of peculiar systems Extend time baselines

How you do that??? GaiaCAPS Doppler MCMC

How you do that??? GaiaCAPS Doppler MCMC

Astrometric model is LINEAR in the relevant quantities Only becomes (a bit) more complicate when combined with RVs, or for highly eccentric orbits (e>0.6)

Conclusions Experience : As ground based transit surveys did for COROT & Kepler… prepares the tools, identifies pitfalls Cool parallaxes NOW : Ground based astrometry, gives your parallaxes NOW at sufficient accuracy (nearby cool stars) When Gaia data is released (residuals, not solutions!) … Combine astrometric solutions Time to pack (at least CAPS, RECONS and a few others) … work continues on L, T and Y dwarfs! (nIR astrometry) First population statistics of ‘long period’ Gas giants around M dwarfs available before Gaia