yeti – search for young transiting planets · transit models instead of a box), adding up images...

YETI – search for young transiting planets

Ronny Errmann, Astrophysikalisches Institut und Universitäts-Sternwarte Jena,in collaboration with:

Ralph Neuhäuser, AIU JenaStefanie Rätz, AIU JenaManfred Kitze, AIU JenaMartin Seeliger, AIU JenaYETI Observers, all over the world

Mercury transit 8. Nov. 06 (SOHO)

Venus transit 6. June 12

Planet validation workshop

Marseille

15. May 2013

Transiting planets

Light curve → planetary radius, orbit inclination;RV follow up → true planetary mass

>300 Transiting Planets known; + CoRoT and Kepler candidates

Motivation

youngest transiting planets:

●Corot 2: 130 – 500 Myr

(from star spots)30 – 40 Myr

(from planet radius)●Corot 20:

100 – 800 Myr (from Li-abundance)

●Wasp 10: 200 – 350 Myr

(from gyro-chronology)

→ younger transiting planets (Radius+true Mass) needed, to test models, and planet formation scenarios

M = 1 MJup

Observation strategies

increase probability for transiting planet: monitoring of many young stars

→ Young open clusters

orbital periods: ~1 to ~10 days transit duration: ~1 to few hours

observation with single telescope: data gaps because of daytime, weather, ...

increase probability for observing transit signal: long continuous observation

→ YETI

→ 1 to 5% of orbit in transit phase

YETI-network (Young Exoplanet Transit Initiative)Gunma

Astronomical Observatory

1.5-m telescope

Xinglong

Observatory90/60 cm

Byurakan

1.0 and 2.6 telescopes

Stara Lesna

Astronomical Institute

0.6-m telescope

Jena

Astrophysical Institute

0.9/0.6-m telescope

Sierra Nevada

1.5-m telescope

Gettysburg

Collage Observatory

0.4-m telescope

Llano del Hato

Observatory

1-m Schmidt telescope

Tenagra II

0.8-m telescope

Swarthmore

0.6-m telescope

Lulin

Lulin Observatory1m Telescope

Nainital

State Observatory1-m telescope

Rozhen

0.6 and 2-m telescopes

Torun

60 cm telescope

Calar Alto

2.2-m telescope

pt5

50 cm telescope

Observatorio Cerro

Armazones

two 5.9’’ telescopes

Mauna Kea

Univ. of Hawaii2.2m telescope

YETI-network (Young Exoplanet Transit Initiative)

YETI cluster

Trumpler 37, 4 Myr, 870 pc

25 Ori8 Myr330 pcS. Raetz

IC 3482 Myr350 pcM. Kitze

Trumpler 37part of H-II region IC 1396

distance: 870 pc (*)

age: 4 to 10 Mio years (*)→ formation of planets finished

Diameter: 1.5°

Extinction: AV = 1.5 mag

Cluster radial velocity v = -15.0 ± 3.6 km/s (*)

18000 stars,500 known members(*)

central part of Trumpler 37 from 90/60cm Schmidt-Telescope Jena,R-Band 60s, FOV: 53' x 53'

*Sicilia-Aguilar et al. (2004-2007),Marschall and van Altena (1987)Contreras et al. (2002)

Photometric precision (night 2013-08-30, 115 data points each)

for 10s exposure time: 163 stars: σ < 5 milli-mag for 120s exposure time: 690 stars: σ < 5 mmag

5351 stars: σ < 30 mmag

Observations Tr 37Jena (Großschwabhausen) 2009 - 2011:

171 nights, 12 500 data points in R filter

in each exposure time

Photometric precision YETI

Tr 37

IC 348 Tr 37

25 Ori

Observations Tr 37Jena (Großschwabhausen) 2009 - 2011:

171 nights, 12 500 data points in R filter

in each exposure time

2010: 3. - 12. Aug.26. - 12. Sept.24. - 30. Sept.

2011:11. - 22. July10. - 22. Aug.9. - 20. Sept.

→ 18500 images from 9 telescopes

YETI campaign runs

→ 28500 images from 11

telescopes

Gunma

Astronomical

Observatory

1.5-m telescope

Xinglong

Observatory

90/60 cm

Byurakan

1.0 and 2.6

telescopes

Stara Lesna

Astronomical

Institute0.6-m

telescope

Jena

Astrophysical

Institute0.9/0.6-m telescope

Sierra Nevad

a

1.5-m telescop

e

Gettysburg

Collage Observat

ory0.4-m

telescope

Llano del

Hato Observatory

1-m Schmidt

telescope

Tenagra II

0.8-m telescope

Swarthmore

0.6-m telescope

Lulin

Lulin Observat

ory1m

Telescope

Nainital

State Observat

ory1-m

telescope

Rozhen

0.6 and 2-m

telescopes

Torun

60 cm telescop

e

Calar Alto

2.2-m telescop

e

pt5

50 cm telescope

Observatorio Cerro Armazones

two 5.9’’ telescope

s

Mauna Kea

Univ. of Hawaii2.2m

telescope

Multi-site campaign on Trumpler 372010cam-paigns

third 2010campaign

third 2011campaign

Multi-site campaign on Trumpler 37

GM Ceph

investigated by YETI:Chen et al. 2012

2010 campaigns2009-2011

Multi-site campaign on Trumpler 37

12 000 data points, but still gaps in the phase folded light curve

P=6.005 d

Multi-site campaign on Trumpler 37

YETI telescope data

no gaps

but slightly bigger scatter, when combining data from different telescopes

Star 118: eclipsing binary (possible member)

Transit-candidates in Trumpler 37

phase folded and binned R-band lightcurve of the Jena data (10 000 data points)

star is active over several days with∆m ≈ 15 milli-mag

R = 15.1 mag 13.4 magP = 1.36491 (1) d 0.736867 (1) dSpT: ≈ G2 ≈ G4

fit with EDT:ΔR

trans = 53.9 ± 0.8 milli-mag 10.7 ± 0.5 milli-mag

ttrans

= 172 ± 2 min 79 ± 1 min

fit with IDL-TAP:I = 87 ± 2° 71 ± 3°R

P/R

*= 0.196 ± 0.004 → ≈ 2 R

Jup0.108 ± 0.007 → ≈ 1 R

Jup

Transit-candidates in Trumpler 37

first transiting candidate from different telescopes:40 cm to 2 m

Transit-candidates

star is active over several days with∆m ≈ 15 milli-mag

Calar Alto 2.2m:ΔI

trans = 51.8 (5) milli-mag

ttrans

= 159.8 (8) min

phase folded and binned R-band lightcurve of the Jena data (10 000 data points)

R = 15.1 mag 13.4 magP = 1.36491 (1) d 0.736867 (1) dSpT: ≈ G2 ≈ G4

fit with EDT:ΔR

trans = 53.9 ± 0.8 milli-mag 10.7 ± 0.5 milli-mag

ttrans

= 172 ± 2 min 79 ± 1 min

fit with IDL-TAP:I = 87 ± 2° 71 ± 3°R

P/R

*= 0.196 ± 0.004 → ≈ 2 R

Jup0.108 ± 0.007 → ≈ 1 R

Jup

Transit-candidates follow-upHigh resolution infrared imaging to check, whether there are other (eclipsing?) stars nearby (in the optical PSF)

→ 8m Subaru AO imaging

J H K2MASS 13.45 12.97 12.89

1 13.50 13.05 12.99

2 17.76 16.88 16.49

3 17.41 17.25

4 17.84 17.25 17.08

first candidate, H-Band

second candidate, K-Band

Separation 1-2: 0.23 arcsec→ 200 au

Transit-candidate 1 follow-upHigh resolution spectra to measure line shift and radial velocity

→ 10m-Keck-I: HIRES spectrograph(+ 1 Spectrum from Hechtochelle at 6m MMT)

Fitting RV and lightcurve simultaneously with PHOEBE- eccentricity = 0.165 / 0.0 - mass ratio = 0.23 / 0.16 → M5 / M6 dwarf- radius ratio = 0.21

e=0.165

Follow-up – Lithium: with Calar Alto 2.2m

weak Lithium line, EW = 0.1 Å no Lithium visible→ no members in the young cluster

Transiting candidate in 25 Ori

Transiting candidate – Jena data

Transiting candidate in 25 Ori

van Eyken et al. 2012

Transiting candidate – Radial velocity

van Eyken et al. 2012

van Eyken et al. 2012

Conclusions and further investigationsWe are able to find transit signals of Jupiter sized planets and do follow up

YETI-network closes observational gaps

Monitoring young clusters: Trumpler 37 (4 Myr), 25 Ori (8 Myr, 9 YETI-campaigns), IC 348 (2 Myr, 3 YETI campaigns), Collinder 69 (1-6 Myr), NGC 1980 (5 Myr)

Problems: faint stars; variable stars

Improved transit search (Bayesian approach for change point detection and fit transit models instead of a box), adding up images

→ more transit candidates expected (especially at late type stars)→ Additional follow-up observations (membership, orbits, masses, …)

Investigations in variability, young eclipsing binaries, membership, and cluster properties

Goal: young planets to constrain formation models, to study planetary interior

?flickr

Thanks for your attention

Color image of Trumpler 37 and STK FoV (Jena telescope data, stitched by Mugrauer)

Work flow:

● data reduction partly done● identify stars in the images (adding to list / using part of list)● finding optimal aperture for one night● aperture photometry on star list● differential photometry (Broeg et al. 2005)

Final lightcurve: ● pre-selecting comparison stars: (similar color, similar brightness,

small separation to target)● differential photometry on all data (telescopes and nights)

Observations

Radial velocity orbit for transit candidate:HIRES spectrograph at 10m-Keck-I telescope

Follow-up - Keck

Cross correlation with artificial spectra:

HJD-2455000 RV [km/s]

466.74372 9.071466.79397 10.548466.88945 11.482468.88121 -47.398468.94959 -48.682521.68193 -3.242

Mass of the small component:MB=0.16±0.02 Msun

(M6 V)