Published by
EDP Sciences
EDP Sciences Journals List
Subscriber Authentication Point
Home All issues Volume 508/ 1 Article
Free access
Issue A&A
Volume 508, Number 1, December II 2009
Page(s) 467 - 478
Section Planets and planetary systems
DOI http://dx.doi.org/10.1051/0004-6361/200912923
Published online 08 October 2009

A&A 508, 467-478 (2009)
DOI: 10.1051/0004-6361/200912923

Mass measurement of a single unseen star and planetary detection efficiency for OGLE 2007-BLG-050

V. Batista1, S. Dong2, A. Gould2, J. P. Beaulieu1, A. Cassan3, G. W. Christie4, C. Han5, A. Udalski6,
and

W. Allen7, D. L. DePoy2, A. Gal-Yam8, B. S. Gaudi2, B. Johnson9, S. Kaspi10, C. U. Lee11, D. Maoz10, J. McCormick12, I. McGreer13, B. Monard7, T. Natusch14, E. Ofek15, B.-G. Park11, R. W. Pogge2, D. Polishook10, A. Shporer10,
(The μFUN Collaboration)

M. D. Albrow16, D. P. Bennett17, S. Brillant18, M. Bode19, D. M. Bramich20, M. Burgdorf21, 14, J. A. R. Caldwell22, H. Calitz23, A. Cole24, K. H. Cook25, Ch. Coutures26, S. Dieters1, 24, M. Dominik27, D. D. Prester28, J. Donatowicz29, P. Fouqué30, J. Greenhill24, M. Hoffman23, K. Horne27, U. G. Jørgensen31, N. Kains27, S. Kane32, D. Kubas1, 18, J. B. Marquette1, R. Martin33, P. Meintjes23, J. Menzies34, K. R. Pollard16, K. C. Sahu35, C. Snodgrass18, I. Steele19, Y. Tsapras36, J. Wambsganss3, A. Williams33, M. Zub3,
(The PLANET/RoboNet Collaboration)

Ł. Wyrzykowski6, 37, M. Kubiak6, M. K. Szymański6, G. Pietrzyński6, 38, I. Soszyński6, O. Szewczyk38, 6, K. Ulaczyk6,
(The OGLE Collaboration)

F. Abe39, I. A. Bond40, A. Fukui39, K. Furusawa39, J. B. Hearnshaw16, S. Holderness41, Y. Itow39, K. Kamiya39, P. M. Kilmartin42, A. Korpela42, W. Lin40, C. H. Ling40, K. Masuda39, Y. Matsubara39, N. Miyake39, Y. Muraki43, M. Nagaya39, K. Ohnishi44, T. Okumura39, Y. C. Perrott45, N. Rattenbury45, T. Saito46, T. Sako39, L. Skuljan40, D. Sullivan47, T. Sumi39, W. L. Sweatman40, P. J. Tristram42, and P. C. M. Yock45
(The MOA Collaboration)

1  Institut d'Astrophysique de Paris, INSU-CNRS, 98 bis Boulevard Arago, 75014 Paris, France
    e-mail: [batista;beaulieu;marquett]@iap.fr
2  Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210, USA
    e-mail: [dong;gould;gaudi]@astronomy.ohio-state.edu
3  Astronomisches Rechen-Institut, Zentrum für Astronomie, Heidelberg University, Mönchhofstr. 12–14, 69120 Heidelberg, Germany
4  Auckland Observatory, Auckland, New Zealand
    e-mail: gwchristie@christie.org.nz
5  Program of Brain Korea, Department of Physics, Chungbuk National University, 410 Seongbong-Rho, Hungduk-Gu, Chongju 371-763, Korea
    e-mail: cheongho@astroph.chungbuk.ac.kr
6  Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland
    e-mail: [udalski;mj;msz;mk;pietrzyn;soszynsk; kulaczyk]@astrouw.edu.pl
7  Bronberg Observatory, Centre for Backyard Astrophysics Pretoria, South Africa
    e-mail: lagmonar@nmsa.org
8  Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot, Israel
    e-mail: avishay.gal-yam@weizmann.ac.il
9  Institute of Astronomy, Cambridge University, Madingley Rd., Cambridge, CB 0HA, UK
    e-mail: bjohnson@ast.cam.ac.uk
10  Wise Observatory, Tel Aviv University, 69978 Tel Aviv, Israel
    e-mail: [dani;shai;david;shporer]@wise.tau.ac.il
11  Korea Astronomy and Space Science Institute, 61-1 Hwaam-Dong, Yuseong-Gu, Daejeon 305-348, Korea
    e-mail: bgpark@kasi.re.kr
12  Farm Cove Observatory, Centre for Backyard Astrophysics, Pakuranga, Auckland New Zealand
    e-mail: farmcoveobs@xtra.co.nz
13  Department of Astronomy, Columbia University, Pupin Physics Laboratories, New York, NY 10027, USA
    e-mail: mcgreer@astro.columbia.edu
14  AUT University, Auckland, New Zealand
    e-mail: tim.natush@aut.ac.nz
15  Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
    e-mail: eran@astro.caltech.edu
16  University of Canterbury, Department of Physics & Astronomy, Private Bag 4800, Christchurch, New Zealand
17  University of Notre Dame, Department of Physics, 225 Nieuwland Science Hall, Notre Dame, IN 46556, USA
    e-mail: bennett@nd.edu
18  European Southern Observatory, Casilla 19001, Vitacura 19, Santiago, Chile
19  Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD, UK
20  Isaac Newton Group, Apartado de Correos 321, 38700 Santa Cruz de La Palma, Spain
21  SOFIA Science Center, Mail stop N211-3, Moffett Field CA 94035, USA
22  McDonald Observatory, 16120 St Hwy Spur 78, Fort Davis, TX 79734, USA
23  Dept. of Physics/Boyden Observatory, University of the Free State, Bloemfontein 9300, South Africa
24  University of Tasmania, School of Maths and Physics, Private bag 37, GPO Hobart, Tasmania 7001, Australia
25  Lawrence Livermore National Laboratory, IGPP, PO Box 808, Livermore, CA 94551, USA
26  DSM/DAPNIA, CEA Saclay, 91191 Gif-sur-Yvette cedex, France
27  SUPA, University of St Andrews, School of Physics & Astronomy, North Haugh, St Andrews, KY16 9SS, UK
28  Physics department, Faculty of Arts and Sciences, University of Rijeka, 51000 Rijeka, Croatia
29  Technical University of Vienna, Dept. of Computing, Wiedner Hauptstrasse 10, Vienna, Austria
30  Observatoire Midi-Pyrénées, UMR 5572, 14 avenue Edouard Belin, 31400 Toulouse, France
31  Niels Bohr Institute, Astronomical Observatory, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
32  NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue Pasadena, CA 91125, USA
33  Perth Observatory, Walnut Road, Bickley, Perth 6076, Australia
34  South African Astronomical Observatory, PO Box 9 Observatory 7935, South Africa
35  Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
36  Astronomy Unit, School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
37  Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
    e-mail: wyrzykow@ast.cam.ac.uk
38  Universidad de Concepción, Departamento de Fisica, Casilla 160–C, Concepción, Chile
    e-mail: szewczyk@astro-udec.cl
39  Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, 464-8601, Japan
40  Institute for Information and Mathematical Sciences, Massey University, Private Bag 102-904, Auckland 1330, New Zealand
41  Computer Science Department, University of Auckland, Auckland, New Zealand
42  Mt. John Observatory, PO Box 56, Lake Tekapo 8770, New Zealand
43  Department of Physics, Konan University, Nishiokamoto 8-9-1, Kobe 658-8501, Japan
44  Nagano National College of Technology, Nagano 381-8550, Japan
45  Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001, New Zealand
46  Tokyo Metropolitan College of Industrial Technology, Tokyo 116-8523, Japan
47  School of Chemical and Physical Sciences, Victoria University, Wellington, New Zealand

Received 17 July 2009 / Accepted 17 September 2009

Abstract
Aims. We analyze OGLE-2007-BLG-050, a high magnification microlensing event ($A\sim 432$) whose peak occurred on 2 May, 2007, with pronounced finite-source and parallax effects. We compute planet detection efficiencies for this event in order to determine its sensitivity to the presence of planets around the lens star.
Methods. Both finite-source and parallax effects permit a measurement of the angular Einstein radius $\theta_{\rm E}=0.48\pm 0.01$ mas and the parallax $\pi_{\rm E}=0.12\pm 0.03$, leading to an estimate of the lens mass $M=0.50\pm0.14\,M_{\odot}$ and its distance to the observer $D_L=5.5\pm0.4$ kpc. This is only the second determination of a reasonably precise (<$30\%$) mass estimate for an isolated unseen object, using any method. This allows us to calculate the planetary detection efficiency in physical units $(r_\perp,m_{\rm p})$, where $r_\perp$ is the projected planet-star separation and $m_{\rm p}$ is the planet mass.
Results. When computing planet detection efficiency, we did not find any planetary signature, i.e. none of the planetary configurations provides a $\Delta\chi^2$ improvement higher than 60, and our detection efficiency results reveal significant sensitivity to Neptune-mass planets, and to a lesser extent Earth-mass planets in some configurations. Indeed, Jupiter and Neptune-mass planets are excluded with a high confidence for a large projected separation range between the planet and the lens star, respectively [0.6–10] and [1.4–4] AU, and Earth-mass planets are excluded with a 10% confidence in the lensing zone, i.e. [1.8–3.1] AU.


Key words: gravitational lensing -- techniques: photometric -- stars: individual: OGLE 2007-BLG-050 -- planetary systems



© ESO 2009

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.