SPITZER AS A MICROLENS PARALLAX SATELLITE: MASS AND DISTANCE MEASUREMENTS OF BINARY LENS SYSTEM OGLE-2014-BLG-1050L

We report the first mass and distance measurements of a caustic-crossing binary system OGLE-2014-BLG-1050 L using the space-based microlens parallax method. Spitzer captured the second caustic crossing of the event, which occurred ~10 days before that seen from Earth. Due to the coincidence that the source-lens relative motion was almost parallel to the direction of the binary-lens axis, the fourfold degeneracy, which was known before only to occur in single-lens events, persists in this case, leading to either a lower-mass (0.2 and 0.07 M_☉) binary at ~1.1 kpc or a higher-mass (0.9 and 0.35 M_☉) binary at ~3.5 kpc. However, the latter solution is strongly preferred for reasons including blending and lensing probability. OGLE-2014-BLG-1050 L demonstrates the power of microlens parallax in probing stellar and substellar binaries.

[1]  K. Horne,et al.  Bayesian analysis of caustic-crossing microlensing events , 2009, 0911.5285.

[2]  K. Ulaczyk,et al.  PATHWAY TO THE GALACTIC DISTRIBUTION OF PLANETS: COMBINED SPITZER AND GROUND-BASED MICROLENS PARALLAX MEASUREMENTS OF 21 SINGLE-LENS EVENTS , 2014, 1411.7378.

[3]  OGLE-2005-BLG-071Lb, THE MOST MASSIVE M DWARF PLANETARY COMPANION? , 2008, 0804.1354.

[4]  Andrew Gould,et al.  MACHO Velocities from Satellite-based Parallaxes , 1994 .

[5]  C. H. Ling,et al.  MOA-2010-BLG-311: A planetary candidate below the threshold of reliable detection , 2012, 1210.6041.

[6]  CHEAP SPACE-BASED MICROLENS PARALLAXES FOR HIGH-MAGNIFICATION EVENTS , 2012, 1205.5801.

[7]  B. Monard,et al.  MOA-2009-BLG-387Lb: a massive planet orbiting an M dwarf , 2011, 1102.0558.

[8]  M. J. Lehner,et al.  First Observation of Parallax in a Gravitational Microlensing Event , 1995, astro-ph/9506114.

[9]  M. Walker.  Microlensed Image Motions , 1995 .

[10]  A. Gould,et al.  MICROLENS MASSES FROM ASTROMETRY AND PARALLAX IN SPACE-BASED SURVEYS: FROM PLANETS TO BLACK HOLES , 2014, 1401.2463.

[11]  Andrew Gould,et al.  Extreme Microlensing toward the Galactic Bulge , 1997 .

[12]  Mareki Honma.  MACHO Mass Determination Based on Space Telescope Observation , 1999 .

[13]  C. H. Ling,et al.  MICROLENSING DISCOVERY OF A POPULATION OF VERY TIGHT, VERY LOW MASS BINARY BROWN DWARFS , 2013, 1302.4169.

[14]  K. Ulaczyk,et al.  BINARY MICROLENSING EVENT OGLE-2009-BLG-020 GIVES VERIFIABLE MASS, DISTANCE, AND ORBIT PREDICTIONS , 2011, 1101.3312.

[15]  Andrew Gould,et al.  Extending the MACHO Search to approximately 10 6 M sub sun , 1992 .

[16]  A. Gould,et al.  Stokes's Theorem Applied to Microlensing of Finite Sources , 1997 .

[17]  J. Beaulieu,et al.  A Complete Set of Solutions for Caustic Crossing Binary Microlensing Events , 1999, astro-ph/9903008.

[18]  Identification of the OGLE-2003-BLG-235/MOA-2003-BLG-53 Planetary Host Star* , 2006, astro-ph/0606038.

[19]  Andrew Gould,et al.  Microlens Masses from 1-D Parallaxes and Heliocentric Proper Motions , 2014, 1408.0797.

[20]  Harvard-Smithsonian CfA,et al.  Stellar Multiplicity , 2013, 1303.3028.

[21]  A. Gould.  Hexadecapole Approximation in Planetary Microlensing , 2008, 0801.2578.

[22]  S. F. Jorgensen,et al.  OGLE-2003-BLG-238: Microlensing Mass Estimate of an Isolated Star* , 2004, astro-ph/0404394.

[23]  C. H. Ling,et al.  OGLE-2013-BLG-0102LA,B: MICROLENSING BINARY WITH COMPONENTS AT STAR/BROWN DWARF AND BROWN DWARF/PLANET BOUNDARIES , 2014, 1407.7926.

[24]  F. Thevenin,et al.  The angular sizes of dwarf stars and subgiants Surface brightness relations calibrated by interferometry , 2004, astro-ph/0404180.

[25]  S. Refsdal,et al.  On the Possibility of Determining the Distances and Masses of Stars from the Gravitational Lens Effect , 1966 .

[26]  Andrew Gould,et al.  REDDENING AND EXTINCTION TOWARD THE GALACTIC BULGE FROM OGLE-III: THE INNER MILKY WAY'S RV ∼ 2.5 EXTINCTION CURVE , 2012, 1208.1263.

[27]  Manchester,et al.  PREDICTIONS FOR MICROLENSING PLANETARY EVENTS FROM CORE ACCRETION THEORY , 2014, 1403.4936.

[28]  K. Ulaczyk,et al.  First Space-Based Microlens Parallax Measurement: Spitzer Observations of OGLE-2005-SMC-001 , 2007, astro-ph/0702240.

[29]  A. Udalski,et al.  MOA-2011-BLG-293LB: FIRST MICROLENSING PLANET POSSIBLY IN THE HABITABLE ZONE , 2013, 1310.3706.

[30]  Andrew Gould,et al.  GEOSYNCHRONOUS MICROLENS PARALLAXES , 2012, 1211.6384.

[31]  B. Gaudi,et al.  Planetary Detection Efficiency of the Magnification 3000 Microlensing Event OGLE-2004-BLG-343 , 2005, astro-ph/0507079.

[32]  K. Ulaczyk,et al.  FIRST SPACE-BASED MICROLENS PARALLAX MEASUREMENT OF AN ISOLATED STAR: SPITZER OBSERVATIONS OF OGLE-2014-BLG-0939 , 2014, 1410.5429.

[33]  Andrew Gould,et al.  SYSTEMATIC ANALYSIS OF 22 MICROLENSING PARALLAX CANDIDATES , 2005, astro-ph/0506183.

[34]  K. Ulaczyk,et al.  SPITZER AS A MICROLENS PARALLAX SATELLITE: MASS MEASUREMENT FOR THE OGLE-2014-BLG-0124L PLANET AND ITS HOST STAR , 2014, 1410.4219.

[35]  A. Gould,et al.  Microlens Parallaxes of Binary Lenses Measured from a Satellite , 2002, astro-ph/0203313.

[36]  L. Casagrande,et al.  THE UBV(RI)C COLORS OF THE SUN , 2012, 1204.0828.

[37]  J. Beaulieu,et al.  GRAVITATIONAL BINARY-LENS EVENTS WITH PROMINENT EFFECTS OF LENS ORBITAL MOTION , 2013, 1306.3744.

[38]  Edward J. Wollack,et al.  Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report , 2015, 1503.03757.

[39]  A. Gal-Yam,et al.  Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars - V. Evidence for a wide age distribution and a complex MDF , 2012, 1211.6848.

[40]  J. Beaulieu,et al.  A systematic fitting scheme for caustic-crossing microlensing events , 2009, 0901.1285.

[41]  A. Udalski.  The Optical Gravitational Lensing Experiment . Real Time Data Analysis Systems in the OGLE-III Survey , 2004 .

[42]  A. Cassan.  An alternative parameterisation for binary-lens caustic-crossing events , 2008, 0808.1527.

[43]  B. Monard,et al.  THE EXTREME MICROLENSING EVENT OGLE-2007-BLG-224: TERRESTRIAL PARALLAX OBSERVATION OF A THICK-DISK BROWN DWARF , 2009, 0904.0249.

[44]  A. Gould.  Resolution of the MACHO-LMC-5 Puzzle: The Jerk-Parallax Microlens Degeneracy , 2003, astro-ph/0311548.

[45]  B. Monard,et al.  EXTREME MAGNIFICATION MICROLENSING EVENT OGLE-2008-BLG-279: STRONG LIMITS ON PLANETARY COMPANIONS TO THE LENS STAR , 2009, 0907.5411.

[46]  A. Gal-Yam,et al.  OGLE-2003-BLG-262: Finite-Source Effects from a Point-Mass Lens , 2003, astro-ph/0309302.

[47]  J. B. Marquette,et al.  ExELS: an exoplanet legacy science proposal for the ESA Euclid mission – I. Cold exoplanets , 2012, 1206.5296.

[48]  A. J. Drake,et al.  Direct detection of a microlens in the Milky Way , 2001, Nature.

[49]  K. Ulaczyk,et al.  Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing , 2008, Science.

[50]  O. Pejcha,et al.  EXTENDED-SOURCE EFFECT AND CHROMATICITY IN TWO-POINT-MASS MICROLENSING , 2007, 0712.2217.

[51]  Andrew Gould,et al.  KEPLER-LIKE MULTI-PLEXING FOR MASS PRODUCTION OF MICROLENS PARALLAXES , 2013, 1310.4208.

[52]  V. Bozza,et al.  Microlensing with an advanced contour integration algorithm: Green's theorem to third order, error control, optimal sampling and limb darkening , 2010, 1004.2796.

[53]  M. Bessell,et al.  JHKLM PHOTOMETRY: STANDARD SYSTEMS, PASSBANDS, AND INTRINSIC COLORS , 1988 .