International Symposium on Planetary Science (IAPS2013)

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1 International Symposium on Planetary Science (IAPS2013) Venue: 3 rd floor of Astronomical Building Shanghai Astronomical Observatory, Chinese Academy of Sciences

2 The follow-up observations of several exoplanet transit events Liyun Zhang & Qingfeng Pi GuiZhou University

3 Outline Background Photometric Observations Light curve analysis Transit timing variation analysis Our future plan

4 Background Figure.1 The movie of transit of extra-solar planet

5 Background The transit of extroplanet can provide information: Transit time, and duration, its relative radii and orbital inclination Mass and density Formation and evolution Collier Cameron et al., 2007; et c

6 Background The study of Transit timing Variation (Diaz et al., 2008; Sozzetti et al., 2009; ) : Reveal the effect of other perturbing planets in the exoplanetary systems (Steffen & Agol 2005) Moons of the transiting exoplanet (Szabo et al. 2006; Simon et al., 2007; Kipping et al., 2009ab.)

7 Our objects Targets: SuperWASP project: WASP-4b, WASP-36b HATNet project: HAT-P-10b/WASP-11b, HAT-P- 19b, HAT-P-20b, HAT-P-25b CoRoT project: XO project: Kepler HD B; Qatar-2b Barge et al , Pollacco et al., 2006; Christian et al. 2006; Borucke et al. 2010

8 Observation Telescope: 85cm telescope+1kx1k CCD at Xinglong station of NAOC. Band:R filter Time: Zhou et al., 2010

9 Deta Mag The light curves 0.05 R band HAT-P-19b HAT-P-19b-comparisonal star Check star - comparisonal star Time (UT) Figure The light curves of serveral extrasolar event. The black represent the different magnitude of our objects and the comparisonal star. The red one represent the different magnitudeof the comparisonal and check star.

10 Deta Mag Deta Mag Deta Mag Deta Mag The light curves HAT-P-19b 0.6 WASP Time (UT) Time (UT) HAT-P-20b HAT-P-25b Time (UT) 0.20 HAT-P-25-comparisonal star Check star - comparisonal star Time (UT) The light curves of serveral extrasolar event. The black represent the different magnitude of our objects and the comparisonal star. The red one represent the different magnitudeof the comparisonal and check star. (2013 in preparing)

11 Light curve analysis Our transit curves are modeled using the JKTEBOP code and adopting the quadratic limb-darkening law (Southworth 2008, 2009) The minimum times and their uncertainties were also determined with the JKTEBOP code and the model parameters.

12 HAT-P-19b HAT-P-19b: K1 dwarf star GSC with period = / days, a mass of 0.84+/ M sun, radius of 0.82+/ R sun, (Hartman et al., 2011).

13 Del Mag The light curve analysis 0.10 HAT-P-19b Observation Model BJD ( ) Figure. The light curves of the observed transits (points) and fitted models (red lines) of the exoplanet systems of HAT-P-19b.

14 Transit parameters of HAT-P-19b Our result Hartman2011 Our Transit minima (BJD) / Our Transit depth: / mag Our Transit width: /- 2 minute 170 +/- 2 minute Orbital inclination i(deg): / /- 0.4 ra+rb: / K(=rb/rA): / / Rms of residuals (mmag) : Reduced chi-dquared form errorbars :4.80 Table.1 Transit and orbital parameters of HAT-P-19b

15 HAT-P-10b HAT-P-10b/WASP11b: The host star is an early to mid K dwarf, with a spectral analysis yielding mass /-0.08 Msun, stellar radius / 0.03 R sun, an effective temperature of 4800+/- 100K (Bakos et al., 2009; West et al., 2009)

16 Del Mag The light curve analysis HAT-P-10b Observation Model BJD ( ) Figure The light curves of the observed transits and fitted models of the exoplanet systemsof HAT-P-10b.

17 Transit parameters of HAT-P-10b Our West2009 Bakos 2009 Our Transit minima (BJD): / Our Transit depth: / mag Our Transit width: /- 1 minute /- 1minute Orbital inclination i(deg): / / ra+rb: / K(=rb/rA): / / Rms of residuals: (mmag) Reduced chi-squared from errorbars: Table.1 Transit and orbital parameters of HAT-P-19b

18 Transit timing variation analysis We also collected the minima times from Exoplanet Transit database (Poddany et al., 2010) and AXA (Amateur exoplanet Archieve). The ETD time timings were transformed from HJD based on UTC into TDB-based BJD using the online applets2 developed by Eastman et al (2010).

19 (O-C) The O-C diagram The Orbital ephemeris (BJD) of HAT-P-19b: / / HAT-P-19b ETD Our observation Polynomial fit Epoch Figure O-C diagrams of the exoplanet systems HAT-P-19b.

20 (O-C) The O-C diagram The Orbital ephemeris (BJD) of HAT-P-10b: / / HAT-P-10b ETD Our observation Polynomial fit Epoch Figure O-C diagrams of the exoplanet systems HAT-P-19b.

21 Conlusion 1. Some orbital parameters of the systems are obtained, which agree to the previous results (West et al. 2009; Bakos et a. 2009; Hellier et al. 2011; etc). 2. The timing residuals giving a hint about a period change? which might be due to the presence of a second planet in the system or the sporadic asymmetries of transit curves due to starspots on stellar surface used by magnetic activity (Steffen & Agol 2005; Lee et al. 2012; etc).

22 Future plan Monitor the exoplanet transit events using 85 cm and 60 cm telescope at Xinglong station, NAOC. Magnetic interaction between an extrasolar planet and its parent star using high-resolution spectra Zhou et al., 2009; Shkolnik et al., 2008)

23 Thanks

24 Kepler 11 system

25 Holman et al., 2004 Variation of transit period

26 HAT-P-19b Hartman J. D., Bakos G. A., Sato B., et al., 2011, Apj, 726, 52

27 West et al., 2009 WASP11b

28 HAT-P-10b HAT-P-10b: / Mjupiter transiting extrasolar planets GSC with period P= / days, transit epoch / and duration / days Bakos G. A., Pal A., Torres G., et al., 2009, APJ, 696, 1950

29 Bakos et al., 2009 HAT-P-10b

31 Transit of Extra-solar Planet (Photometry)

32 WASP 43b A hot Jupiter transiting a K7V star every 0.81 d. At 0.6 M sun the host star has the lowest mass of any star (15.6 days rotation period). The planet has a mass of 1.8 Jupiter. (Hellier et al., 2011)

33 Del Mag The light curve analysis WASP observation Model Epoch The light curves of the observed transits and fitted models of the exoplanet systems. WASP43

34 (O-C) WASP 43b O-C WASP ETC Our observation Polynomial fit Epoch / /

35 Transit parameters of WASP 43b ra+rb? K(=rb/rA)? Orbital inclination i(deg)? Our Transit minima (BJD) / Our Transit depth= / mag Our Transit width= 69.5a Rms of residuals (mmag) Reduced chi-squared from errorbars Epoch: / The Orbital ephemer (BJD) is / / Stellar mass= M_sun Stellar radius= R_sun Orbital inclination= deg Planet radius= R_jup

HD Transits HST/STIS First Transiting Exo-Planet. Exoplanet Discovery Methods. Paper Due Tue, Feb 23. (4) Transits. Transits.

HD Transits HST/STIS First Transiting Exo-Planet. Exoplanet Discovery Methods. Paper Due Tue, Feb 23. (4) Transits. Transits. Paper Due Tue, Feb 23 Exoplanet Discovery Methods (1) Direct imaging (2) Astrometry position (3) Radial velocity velocity Seager & Mallen-Ornelas 2003 ApJ 585, 1038. "A Unique Solution of Planet and Star