MOA 2010-BLG-477Lb: CONSTRAINING THE MASS OF A MICROLENSING PLANET FROM MICROLENSING PARALLAX, ORBITAL MOTION, AND DETECTION OF BLENDED LIGHT

Bachelet, E.; Shin, In-Gu; Han, Cheongho; Fouqué, P.; Gould, Andrew; Menzies, John; Beaulieu, J. P.; Bennett, D. P.; Bond, I. A.; Dong, Subo; Heyrovsky, David; Marquette, J. B.; Marshall, J. L.; Skowron, J.; Street, R. A.; Sumi, T.; Udalski, A.; Abe, L.; Agabi, Karim; Albrow, M. D.; Allen, William H.; Bertin, E.; Bos, M.; Bramich, D. M.; Chavez, Joy M.; Christie, Grant; Cole, A. A.; Crouzet, Nicolas; Dieters, S.; Dominik, M.; Drummond, J.; Greenhill, J.; Guillot, T.; Henderson, Calen B.; Hessman, F. V.; Horne, K.; Hundertmark, M.; Johnson, J. A.; Jørgensen, U. G.; Kandori, Ryo; Liebig, C.; Mékarnia, D.; McCormick, J.; Moorhouse, D.; Nagayama, Takahiro; Nataf, David M.; Natusch, T.; Nishiyama, Shogo; Rivet, Jean‐Pierre; Sahu, Kailash C.; Shvartzvald, Yossi; Thornley, G.; Tomczak, Adam; Tsapras, Y.; Yee, Jennifer C.; Batista, V.; Bennett, C. S.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Corrales, E.; Coutures, C.; Prester, D. Dominis; Donatowicz, J.; Kubas, D.; Martín, Roland; Williams, A.; Zub, M.; Almeida, L. A.; Depoy, D. L.; Gaudi, B. Scott; Hung, Li Wei; Jablonski, F.; Kaspi, S.; Klein, Nir; Lee, C.-U.; Lee, Y.; Koo, Jae‐Rim; Maoz, Dan; Muñoz, J. A.; Pogge, Richard W.; Polishook, David; Shporer, Avi; Abe, F.; Botzler, C. S.; Chote, P.; Freeman, Matthew; Fukui, A.; Furusawa, K.; Harris, P.; Itow, Y.; Kobara, S.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyake, N.; Ohmori, K.; Ohnishi, Koji; Rattenbury, N. J.; Saito, To.; Sullivan, D. J.; Suzuki, D.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; Szymański, M. K.; Soszyński, I.; Kubiak, M.; Poleski, R.; Ulaczyk, K.; Pietrzyński, G.; Wyrzykowski, Ł.; Kains, N.; Snodgrass, C.; Steele, I. A.; Alsubai, K. A.; Bozza, V.; Browne, P.; Burgdorf, M.; Novati, S. Calchi; Dodds, P.; Dreizler, S.; Finet, F.; Gerner, T.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Kerins, E.; Mancini, L.; Mathiasen, M.; Penny, Matthew T.; Proft, S.; Rahvar, S.; Ricci, Davide; Scarpetta, G.; Schäfer, Sebastian; Schönebeck, F.; Southworth, J.; Surdej, Jean; Wambsganß, J.

doi:10.1088/0004-637x/754/1/73

Cited by 67 publications

(39 citation statements)

References 74 publications

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“…If the system has a mass ratio that overlaps that possible for stellar binaries then it is likely, first, that it will not be analyzed in detail, and second, that unless its parallax is measured, it will not be recognized as a planet. Table 1 lists the distances and relative proper motions of the microlensing planet hosts in our sample, and the method by Gould et al 2006;(8) Beaulieu et al 2006;(9) Bennett et al 2010;(10) Gaudi et al 2008;(11) Kubas et al 2012;(12) Gould et al 2010a;(13) Bennett et al 2008;(14) Sumi et al 2010;(15) Dong et al 2009a;(16) Poleski et al 2014;(17) Janczak et al 2010;(18) Koshimoto et al 2014;(19) Suzuki et al 2014;(20) Muraki et al 2011;(21) Miyake et al 2011;(22) Batista et al 2011;(23) Furusawa et al 2013;(24) Rattenbury et al 2015;(25) Bachelet et al 2012;(26) Kains et al 2013;(27) Bennett et al 2014;(28) Skowron et al 2015;(29) Batista et al 2014;(30) …”

Section: Measuring Distancesmentioning

confidence: 99%

Is the Galactic Bulge Devoid of Planets?

Penny

Henderson

Clanton

2016

ApJ

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Considering a sample of 31 exoplanetary systems detected by gravitational microlensing, we investigate whether or not the estimated distances to these systems conform to the Galactic distribution of planets expected from models. We derive the expected distribution of distances and relative proper motions from a simulated microlensing survey, correcting for the dominant selection effects that affect the planet detection sensitivity as a function of distance, and compare it to the observed distribution using Anderson-Darling (AD) hypothesis testing. Taking the relative abundance of planets in the bulge to that in the disk, f bulge , as a model parameter, we find that our model is only consistent with the observed distribution for f bulge < 0.54 (for a p-value threshold of 0.01) implying that the bulge may be devoid of planets relative to the disk. Allowing for a dependence of planet abundance on metallicity and host mass, or an additional dependence of planet sensitivity on event timescale does not restore consistency for f bulge = 1. We examine the distance estimates of some events in detail, and conclude that some parallax-based distance estimates could be significantly in error. Only by combining the removal of one problematic event from our sample and the inclusion of strong dependences of planet abundance or detection sensitivity on host mass, metallicity and event timescale are we able to find consistency with the hypothesis that the bulge and disk have equal planet abundance.

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Section: Measuring Distancesmentioning

confidence: 99%

Is the Galactic Bulge Devoid of Planets?

Penny

Henderson

Clanton

2016

ApJ

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“…While more accurate limbdarkening models are available, they are not commonly used in microlensing analyses due to the complexity introduced by combining data from many sources (Bachelet et al 2012 discussed this in more detail). The values of u λ for each passband were calculated from the Kurucz ATLAS9 stellar atmosphere models presented by Kurucz (1979) using the method of Heyrovský (2007).…”

Section: Finite Sourcementioning

confidence: 99%

“…Sixteen systems have been published to date, 67 and thanks to large-scale galactic lensing surveys and efficient follow-up, each season's bulge observing campaign is now producing a regular yield of new discoveries (e.g., Bachelet et al 2012;Yee et al 2012;Miyake et al 2012). Of these 16 companions, 3 are giant planets orbiting M-dwarf stars: OGLE-2005-BLG-071Lb, a 3.8 M J planet (Dong et al 2009); MOA-2009-BLG-0387Lb, with an M P = 2.5 M J planet (Batista et al 2011);and MOA-2011-BLG-293Lb, which hosts a 2.4 M J companion (Yee et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Moa-2010-BLG-073l: An M-Dwarf With a Substellar Companion at the Planet/Brown Dwarf Boundary

Street¹,

Choi²,

Tsapras³

et al. 2013

ApJ

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We present an analysis of the anomalous microlensing event, MOA-2010-BLG-073, announced by the Microlensing Observations in Astrophysics survey on 2010 March 18. This event was remarkable because the source was previously known to be photometrically variable. Analyzing the pre-event source light curve, we demonstrate that it is an irregular variable over timescales >200 days. Its dereddened color, (V − I ) S,0 , is 1.221 ± 0.051 mag, and from our lens model we derive a source radius of 14.7 ± 1.3 R , suggesting that it is a red giant star. We initially explored a number of purely microlensing models for the event but found a residual gradient in the data taken prior to and after the event. This is likely to be due to the variability of the source rather than part of the lensing event, so we incorporated a slope parameter in our model in order to derive the true parameters of the lensing system. We find that the lensing system has a mass ratio of q = 0.0654 ± 0.0006. The Einstein crossing time of the event, t E = 44.3 ± 0.1 days, was sufficiently long that the light curve exhibited parallax effects. In addition, the source trajectory relative to the large caustic structure allowed the orbital motion of the lens system to be detected. Combining the parallax with the Einstein radius, we were able to derive the distance to the lens, D L = 2.8 ± 0.4 kpc, and the masses of the lensing objects. The primary of the lens is an M-dwarf with M L,1 = 0.16 ± 0.03 M , while the companion has M L,2 = 11.0 ± 2.0 M J , putting it in the boundary zone between planets and brown dwarfs.

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“…For consistency, we decided to reprocess the RoboNet/LCOGT images using pySIS. MOA images, both from MOA-I and from MOA-II telescopes, were reprocessed using the method described in a previous paper (Bachelet et al 2012). In the MOA-II images, the target unfortunately falls close to a series of bad columns, which sometimes compromises photometric precision.…”

Section: Data Sets: Observations and Data Reductionsmentioning

confidence: 99%

“…We adjust those parameters as in Appendix C of Bachelet et al (2012) and in Miyake et al (2012) by using a standard cumulative distribution for Gaussian errors. If the dispersion of data is well represented by the original error bars, we set f = 1 and e min = 0.…”

Section: Data Analysis: a Noise Modelmentioning

confidence: 99%

A brown dwarf orbiting an M-dwarf: MOA 2009–BLG–411L

Bachelet¹,

Fouqué²,

Han³

et al. 2012

A&A

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Context. Caustic crossing is the clearest signature of binary lenses in microlensing. In the present context, this signature is diluted by the large source star but a detailed analysis has allowed the companion signal to be extracted. Aims. MOA 2009-BLG-411 was detected on August 5, 2009 by the MOA-Collaboration. Alerted as a high-magnification event, it was sensitive to planets. Suspected anomalies in the light curve were not confirmed by a real-time model, but further analysis revealed small deviations from a single lens extended source fit. Methods. Thanks to observations by all the collaborations, this event was well monitored. We first decided to characterize the source star properties by using a more refined method than the classical one: we measure the interstellar absorption along the line of sight in five different passbands (VIJHK). Secondly, we model the lightcurve by using the standard technique: make (s, q, α) grids to look for local minima and refine the results by using a downhill method (Markov chain Monte Carlo). Finally, we use a Galactic model to estimate the physical properties of the lens components. Results. We find that the source star is a giant G star with radius 9 R . The grid search gives two local minima, which correspond to the theoretical degeneracy s ≡ s −1 . We find that the lens is composed of a brown dwarf secondary of mass M S = 0.05 M orbiting a primary M-star of mass M P = 0.18 M . We also reveal a new mass-ratio degeneracy for the central caustics of close binaries. Conclusions. As far as we are aware, this is the first detection using the microlensing technique of a binary system in our Galaxy composed of an M-star and a brown dwarf.

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MOA 2010-BLG-477Lb: CONSTRAINING THE MASS OF A MICROLENSING PLANET FROM MICROLENSING PARALLAX, ORBITAL MOTION, AND DETECTION OF BLENDED LIGHT

Cited by 67 publications

References 74 publications

Is the Galactic Bulge Devoid of Planets?

Is the Galactic Bulge Devoid of Planets?

Moa-2010-BLG-073l: An M-Dwarf With a Substellar Companion at the Planet/Brown Dwarf Boundary

A brown dwarf orbiting an M-dwarf: MOA 2009–BLG–411L

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