SOCHIAS Santiago, January - 09.

Sergio Hoyer MirandaDepartamento de Astronomía

Universidad de Chile

1

Introduction

Ogle Candidates: OGLE-TR-182 OGLE-TR-131 OGLE-TR-109

Transit Timing Variations (TTV): OGLE-TR-111b

Ongoing Survey

SOCHIAS Santiago, January 09

Outline

Introduction

SOCHIAS Santiago, January 09

Exoplanetary Transits:

55 Transiting Planets has been detected.*

False Positives: - Statistics (photometric noise) - Instrumentals (errors in the photometry) - Astrophisycs ( binary or multiple systems )

Parameters we can infer:

Planet Radius, Orbital Period Orbit Inclination Tc,Td (with RV’s) Planet DENSITY

OGLE-TR-182

SOCHIAS Santiago, January 09

Data:GMOS - GEMINI South i ‘ & g’ band

i-band depth consistent with a Neptune-sizedTransiting planet.

OGLE-TR-182

SOCHIAS Santiago, January 09

Data:GMOS - GEMINI South i ‘ & g’ band

i-band depth consistent with a Neptune-sizedTransiting planet.

but…..

Eclipsing binary blended with a background reddened GIANT(Hoyer et al. 2007)

OGLE-TR-131

SOCHIAS Santiago, January 09

i band Light Curve

OGLE-TR-131

SOCHIAS Santiago, January 09

Using colors and low resolution spectra we conclude is a K2III

OGLE-TR-109

SOCHIAS Santiago, January 09

Another candidate:

Host Star: F0V Rstar = 1.5 Rsun fast rotating

Preliminary Results:

Rplanet = 1.3 Rjup

Inclination = 76 degrees

Period = 0.589 days

Transit Timing Variations

SOCHIAS Santiago, January 09

•In general Transit Detection is biased towards Giants Exoplanets. The smallest Transiting Planet detected until now is a Neptune-sized (HAT-P-11b) .

• TTVs: short term variations in Tc due gravitational interaction of the transiting planet with an unseen companion.

• TTVs could potentially detect down to Earth-mass planets from ground based telescopes.

• Also long term variations of Tc can be produce by the presence of another planet in the system (orbital precession)

*exoplanet.eu

Transit Timing Variations: OGLE-TR-111b

SOCHIAS Santiago, January 09

Possible origin of the variations:

• Exomoon ?

• Earth-mass planet perturbing the transiting planet ? Diaz, R. et al. 2008

Winn et al. 07

Minniti et al. 2007Our work

(Kipping, D. M. MNRAS 2009). 

Transit Timing Variations: OGLE-TR-111b

SOCHIAS Santiago, January 09

3 transits were observed with FORS1 -2 in VLT

V-band Light Curve of OGLE-TR-111b

Transit Timing Variations

SOCHIAS Santiago, January 09

We are currently performing a search for unseen companions of transiting planets using TTV’s.

Recently obtained data from GEMINI Observatory, SOAR Telescope and CTIO 1 mt Telescope.

Working in a code to do Deconvolution Photometry.

Is also important to monitoring long term variations of the central Time of Transits.