Guillem Anglada-Escude (1,2) Alan P. Boss(1) Alycia Weinberger (1) Ian Thompson (1)

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

a

1º

3474 km

1’

120 km

1/60

1/60

1’’

2 km

1/1000

2 m

1 mas

2 cm

10 mas1/100

1 mas

A closer look at astrometry…

Astrometric recipes

masMM

dR

mm sun

pc

AU

jup

p *

a

Exo-Jupiter formula

3*M

MdR

mm

as sun

pc

AU

Earth

pma

Exo-Earth formula

G dwarf @ 10 pc

M dwarf @ 10 pc

0.1 mas 1.0 masMan on

the moonBook on

the moon

3 mas0.3 masPaper

width on the moon

Euro width on the moon

Gaia/ESA Ground based

Ground based AstrometryWhy 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

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 http://www.dtm.ciw.edu/anglada/

•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!

http://www.dtm.ciw.edu/anglada/

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 = 4

0.1HZ

0.5 HZ

GJ 317 GJ 1214VB 10

Astrometric detectionPravdo & Shaklan 2010 ApJ

P=270 daysM ~ 6 Mjup

D = 7 pcGalactic plane

Doppler candidateJohnson et al 2007, ApJ

P=690 daysM sin i ~ 2 Mjup

D = 9.6 pc[Fe/H] = -0.3??

Transit + Doppler planetCharbonneau et al. 2009, Nat

P=1.83 daysM sin i ~ 6 Meartj

D = 12.0 pcRadius 15% larger??

Lessons learned from individual targets

? ? ?

Lessons learned from individual targets : VB 10

Black & Scargle 1982

Astrometry2 x offsets 2 x Proper motions 1 x Parallax

HD 125612Fischer et al. 2007

Doppler1xoffset

GJ 317, Anglada-Escude et al. 2012


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/MagellanBean et al. 2011, RV follow-up with CRIRES/VLT

Lazorenko et al. 2011, Astrometric follow-up


49.9 days 270 days


GJ 317 GJ 1214VB 10






D = 9.6 pc[Fe/H] = -0.3??





(need better understanding of sampling)

d = 9.6 pcM* = 0.24 Msun

M sin i = 1.85 Mjup

P = 692 days, a = 0.95 AU

masMM

dR

mm

sun

pc

AU

jup

p *

a

Exo-Jupiter formula

0.78 mas

Jonhson, Butler et al. ApJ 2007

Lessons learned from individual targets : GJ 317

d = 14.9 pc0.32 mas M* = 0.42 Msun

M sin i = 1.8 Mjup

P = 692 days a = 0.95 AU

d = 9.6 pca =0.78 mas


𝒗 𝒓 (𝒕 )=𝜸+𝑲 ¿𝑿 (𝒕 )=𝑿𝟎+𝝁𝜶 (𝒕− 𝒕𝟎 )+∆𝜶 (𝒕)−𝝅 𝒙𝒐𝒃𝒔 ∙ �̂�𝜶𝑨𝑼

𝒀 (𝒕 )=𝒀 𝟎+𝝁𝜹 (𝒕− 𝒕𝟎 )+∆𝜹 (𝒕 )−𝝅 𝒙𝒐𝒃𝒔 ∙ �̂�𝜹𝑨𝑼


𝐿∝𝐸𝑋𝑃 [− 12𝜒2]

Likelihood function

Period

Mas

sLessons learned from individual targets : GJ 317

𝐿∝𝐸𝑋𝑃 [− 12𝜒2]

Likelihood function

Period

Mas

s

Provides optimal sampling in highly dimensional spaces

N = 13

Run a few million steps and you are done!


First exoplanet “confirmed” with Ground based astrometry!



GJ 317 GJ 1214



D = 9.6 pc[Fe/H] = -0.3??




VB 10







GJ 317 GJ 1214VB 10






D = 9.6 pc[Fe/H] = -0.3??




Combine RV+Astrometry




CAPS Astrometry (new)RMS < 1.0 mas

HARPS-TERRA RVs (updated)

30 transit times and updated

Transit observablesSada et al, 2010, Carter et al. 2011, Kundurthy et al., 2011

• K band, low res(new)• 4 Optical bands• 3x2MASS bands• 4xWISE bands (new)


d

M*

L*

Teff

14.47 (0.14) pc

0.175 (0.009) Ms

3.9 10-3 Ls

3200 K

12.9 (1.0) pc

0.155 Ms

3.3 10-3Ls

2900 K

+12%+13%

+19%+10%

Previous NEW!


GJ 317 GJ 1214VB 10






D = 9.6 pc[Fe/H] = -0.3??








GJ 317 GJ 1214VB 10






D = 9.6 pc[Fe/H] = -0.3??



D = 14.5 pcEverything is good!


Transits+RV, astrometry

Simultaneous FIT!



‘Other’ exoplanet related programs… 10 years before Gaia

Young field M dwarfs (UV and X ray sources) from Shkolnik et al. 2009 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. 2011 (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???

𝒗 𝑯𝑰𝑹𝑬𝑺(𝒕 )=𝜸𝟏+𝑲 ¿

𝒗 𝑯𝑨𝑹𝑷𝑺(𝒕 )=𝜸𝟐+𝑲 ¿

𝒖 (𝒕 )=𝒖𝟎+𝝁 ′𝜶 (𝒕−𝒕𝟎 )−𝝅𝒙𝒐𝒃𝒔 ∙ �̂�𝜶𝑨𝑼 +∆𝜶(𝒕)

v

𝒓=¿(�⃗�−�⃗�𝟎) �⃗�>¿

Gaia

𝑿 (𝒕 )=𝑿𝟎+𝝁𝜶 (𝒕−𝒕𝟎)−𝝅�⃗�𝒐𝒃𝒔 ∙ �̂�𝜶𝑨𝑼 +∆𝜶 (𝒕)

𝒀 (𝒕)=𝒀 𝟎+𝝁𝜹 (𝒕− 𝒕𝟎 )−𝝅𝒙𝒐𝒃𝒔 ∙ �̂�𝜹𝑨𝑼 +∆𝜹 (𝒕 )

CAPS

DopplerM

CMC

𝑿 (𝒕 )=𝑿𝟎+𝝁𝜶 (𝒕−𝒕𝟎)−𝝅𝒑 (𝒕 )+𝑨𝒄𝒐𝒔 (𝒘𝒕 )+𝑩𝒔𝒊𝒏 (𝒘𝒕 )

𝒀 (𝒕 )=𝒀 𝟎+𝝁𝜹 (𝒕− 𝒕𝟎 )−𝝅𝒒(𝒕 )+𝑪𝒄𝒐𝒔 (𝒘𝒕 )+𝑫𝒔𝒊𝒏(𝒘𝒕 )

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

Guillem Anglada-Escude (1,2) Alan P. Boss(1) Alycia Weinberger (1) Ian Thompson (1)

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