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BINARIES - Key to Comprehension of the Universe, Brno, Czech Republic, June 8-12, 2009

Precise Radial Velocity Measurements: Key to Discover Low-mass Companions and Exoplanets Around Stars. Selim O. SELAM Mesut YILMAZ Ankara University Observatory Hideyuki IZUMIURA Okayama Astrophysical Observatory-NAOJ Ilfan BIKMAEV Kazan State University Bun’ei SATO

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BINARIES - Key to Comprehension of the Universe, Brno, Czech Republic, June 8-12, 2009

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  1. Precise Radial Velocity Measurements: Key to Discover Low-mass Companions and Exoplanets Around Stars Selim O. SELAM Mesut YILMAZ Ankara University Observatory Hideyuki IZUMIURA Okayama Astrophysical Observatory-NAOJ Ilfan BIKMAEV Kazan State University Bun’ei SATO Tokyo Institute of Technology Eiji KAMBE Okayama Astrophysical Observatory-NAOJ Varol KESKİN Ege University Observatory BINARIES - Key to Comprehension of the Universe, Brno, Czech Republic, June 8-12, 2009

  2. ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

  3.  Cephei (K1 IVe + M4V) Confirmed by Hatzes et al., 2003, ApJ, 599, 1383 Campbell, Walker & Yang, 1988 ApJ, 331, 902 K =  25 m/s Porb = 2.7 years M sini = 1.7 Mjup ? M sini = 1.7 Mjup Porb = 2.48 years a = 2.13 AU  Radial velocity(m/s) Years HD 114762(F9 V) Confirmed by Marcy in 1996 Latham et al., 1989, Nature, 339, 38 M sini = 11.02 Mjup Porb = 84.03 days a = 0.35 AU  M sini = 11 Mjup Porb = 84 days Vr (km/s) i = ? a Brown Dwarf ? Orbital Phase

  4. PSR 1257 + 12 Wolszczan & Frail, 1992, Nature, 355, 145 M sini : 3.4 M & 2.8 M Porb : 66.6 days & 98.2 days a : 0.36 AU & 0.47 AU 3th planet ?!

  5. G0 V 5.1 pc G2.5 V 17.8 pc 70 Vir b Marcy & Butler 1996 ApJ, 464, L147 M sini = 6.6 Mjup Porb = 116.6 days a = 0.43 AU 47 UMa b Butler & Marcy 1996 ApJ, 464, L153 M sini = 2.39 Mjup Prot = 2.98 years a = 2.1 AU G1 V 14.1 pc 51 Peg b Mayor & Queloz 1995 Nature, 378, 355 M sini = 0.47 Mjup Porb = 4.231 days a = 0.05 AU

  6. by 1st June 2009 • Doppler Technique • Astrometry • Planetary Transits • Microlensing • Direct Imaging • Timing • Polarimetry 322 (>90% DT) 59 8 11 7 0 348 Data from: Schneider J., 2009, http://exoplanet.eu

  7. Data From: Schneider J., 2009, http://exoplanet.eu

  8. DOPPLER TECHNIQUE • Jupiter 12.4 m/sec • Saturn 2.7 m/sec • Earth 0.1 m/sec • Mercury 0.01 m/sec  Limitations in precision of measured radial velocities arise from spatial and temporal differences in the way of obtaining the stellar and reference spectra a) taken at different times b) taken over different optical paths c) flexture and thermal changes in the spectrometer 1 km/s

  9. Griffin & Griffin, 1973 (MNRAS, 162, 243 and MNRAS, 162, 255) Telluric Lines ( 6800-7400 Å)  40 - 50 m/sn

  10. P FT Ao Ao 1/P w t Monochromatic Light wave Delta Function Ao Ao 1/P 1/P w w 1/P INSTRUMENTAL PROFILE (IP) Perfect Spectrograph Real Spectrograph The instrumental profile produces a 2-4 pixel wide “BLURING” effect and can be represented with Gaussian profiles. Ao 1/P w Instrumental Profile

  11. INSTRUMENTAL PROFILE (IP) There is no problem with the IP if it not chance its character with time stable symmetic IP Dl DV IP with time dependent character DV ~ 40-50 m/s stable asymmetic IP

  12. DOPPLER TECHNIQUE A Thermally Stabilized Gas Absorption Cell in the front of the entrance slit of a spectrograph Overlays thousands of sharp I2 lines between ll 5000-6000 Å onto stellar spectrum Iodine Cell (I2) gas filter Butler et al.,1996,PASP, 108, 500 3 m/s ! (Lick 3m) 1 m/s ! (Keck 10m)

  13. DOPPLER TECHNIQUE THE MODEL (Butler et al., 1996, PASP, 108, 500 / Endl et al., 2000, A&Ap, 362, 585 / Takeda et al., 2002, PASJ, 54, 113 / Sato et al., 2002, PASJ, 54, 873) The observed stellar spectrum through an I2-cell I(l) is expressed as the product of intrinsic stellar spectrum S(l), and the transmission function of the I2-cell A(l) convolved with a modelledIP I(l) : Observed “star+I2” composite spectrum S(l) : Intrinsic stellar spectrum Dl: Stellar Doppler shift A(l) : “Transmission function of the I2 Cell”- I2 template IP : “Instrumental Profile” – produced by the 1D Point Spread Function of the detector k : normalization factor * : represents the convolution process made by FT

  14. DOPPLER TECHNIQUE THE MODEL LICK Group Valenti et al., 1995, PASP, 107, 966 Butler et al., 1996, PASP, 108, 500 ESO Group Endl et al., 2000, A&Ap, 362, 585 OKAYAMA Group Takeda et al., 2002, PASJ, 54, 113 Sato et al., 2002, PASJ, 54, 873 The modeling process can be divided into the following three majorsteps (Endl et al., 2000): Step 1: Reconstruction of instrumental effects and spectrographinstrumental profiles by modeling pure iodine spectra using ahigh resolution Fourier Transform Spectrum (FTS) of the I2-cell. Transmission function of the I2-cell, A(l) is also obtained at this step. Step 2:Obtaining the “template” stellar spectra by deconvolvinga pure star spectrum (taken without the I2-cell) with theIPs reconstructed in step 1. Step 3: Complete modeling of the star+I2spectrum. Transmission function of the I2-cell from step 1 and the deconvolved “template” stellar spectrumfrom step 2 serve as model templates,A(l) and S(l) to synthesize the observation.The Doppler shift between the iodine reference and thestellar absorption lines is determined with high accuracy.

  15. Turkish National Observatory (TUG) RTT150 Telescope - CES Taurus Mountains-Bakirlitepe / Antalya, h=2500 m, 36º 49' 27“ N, 30º 20' 08“ E http://www.tug.tubitak.gov.tr RTT150 Telescope Ø = 1.5 meters Coude f/48 Cassegrain f/7.7 Coude Echelle Spectrograph (CES) R = Dl/l = 40000 slit width = 1.5 arcsec (500 mm) ll 3800 – 10000 Å (85 orders) SAO-RAS 1Kx1K 16mm pix LN cooled F.I. CCD Registered wavelength interval on CCD ll 3900 – 8700 Å(68 orders)

  16. To start exoplanet searches at Turkish National Observatory (TUG) we established an international collaboration between Turkish-Russian-Japanese colleagues An I2-Cell and its temperature controller was produced by our Japanese colleagues at Okayama Astrophysical Observatory (OAO) and successfully integrated to RTT150-CES on OCTOBER 2007 (for technical details, see: Kambe et al., 2002, PASJ, 54, 865)

  17. First Ligth with new I2-Cell 26 October 2007

  18. Test Observations 2007-II : TUG_RTT150.07.47 test 2008-I : TUG_RTT150.08.11 test 2008-II : TUG_RTT150.08.47 test + targets 2009-I : 09A_RTT150-439-2 test + targets 44 allocated nights distributed within 1.5 YEARS Radial Velocity Standards and well known Planet-harboring Stars whose RV behaviors are well established within a few m/sn

  19. Radial Velocity Standards Planet-harboring Stars iot Per tau Cet

  20. ACHIEVED RV PRECISION • For V=3 mag stars under ~15 min. exposure time (S/N=200) • 10-15 m/s • For V=6.5 mag stars under 30 min. exposure time (S/N=100) • ~25 m/s • TARGET STARS OF OUR PROJECT • 50 G-type giants • showing RMS>25 m/s RV variation in previous RV surveys • slow rotators, many sharp absorption lines • relatively stable against pulsations • relativelylow surface activity

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