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