A Low-Mass Planet with a Possible Sub-Stellar-Mass Host in Microlensing Event MOA-2007-BLG-192

By D. Bennett, I. Bond, A. Udalski, T. Sumi, F. Abe, A. Fukui, K. Furusawa, J. Hearnshaw, S. Holderness, Y. Itow and 37 more. 2008

203 citations recorded by the source corpus.

We report the detection of an extrasolar planet of mass ratio q ∼ 2 × 10−4 in microlensing event MOA-2007-BLG-192. The best-fit microlensing model shows both the microlensing parallax and finite source effects, and these can be combined to obtain the lens masses of M = 0.060+ 0.028−0.021 M☉ for the primary and m = 3.3+ 4.9−1.6 M⊕ for the planet. However, the observational coverage of the planetary deviation is sparse and incomplete, and the radius of the source was estimated without the benefit of a source star color measurement. As a result, the 2 σ limits on the mass ratio and finite source measurements are weak. Nevertheless, the microlensing parallax signal clearly favors a substellar mass planetary host, and the measurement of finite source effects in the light curve supports this conclusion. Adaptive optics images taken with the Very Large Telescope (VLT) NACO instrument are consistent with a lens star that is either a brown dwarf or a star at the bottom of the main sequence. Follow-up VLT and/or Hubble Space Telescope (HST) observations will either confirm that the primary is a brown dwarf or detect the low-mass lens star and enable a precise determination of its mass. In either case, the lens star, MOA-2007-BLG-192L, is the lowest mass primary known to have a companion with a planetary mass ratio, and the planet, MOA-2007-BLG-192Lb, is probably the lowest mass exoplanet found to date, aside from the lowest mass pulsar planet.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/a0ec54935093dcdbc18f6514df783aea295f754c

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In Astronomy and Astrophysics

1. J. Southworth
2. D. Charbonneau
3. M. Mayor
4. S. Udry
5. C. Mordasini
6. M. Perryman
7. C. Lovis
8. Nuno C. Santos

Citations in the corpus

• The HARPS search for southern extra-solar planets - XIII. A planetary system with 3 super-Earths (4.2, 6.9, and 9.2 M) (2008, background): “Two planets with masses possibly in the range of super-Earths have been announced: a planet of about 5.5 M ⊕ orbiting a low-mass star (Beaulieu et al. 2006) and a still less massive object, of only 3.3 M ⊕ , probably gravitationally bound to a brown dwarf (Bennett et al. 2008).”
• Microlensing Surveys for Exoplanets (2012, background): “F or p er so na l u se o nl y. AA50CH10-Gaudi ARI 16 July 2012 12:29 MOA-2007-BLG-192Lb appears to be another member of this class, also being a very lowmass, cool planet likely orbiting a star with a mass near the hydrogen-burning limit (Bennett et al. 2008).”
• A COLD NEPTUNE-MASS PLANET OGLE-2007-BLG-368Lb: Cold neptunes are common (2009, methodology): “So far 8 planetary systems with 9 planets have been found by this technique (Udalski et al. 2005; Beaulieu et al. 2006; Gould et al. 2006; Gaudi et al. 2008; Bennett et al. 2008; Dong et al. 2009b; Janczak et al. 2010), which have very distinct properties from those detected by other techniques.”
• FREQUENCY OF SOLAR-LIKE SYSTEMS AND OF ICE AND GAS GIANTS BEYOND THE SNOW LINE FROM HIGH-MAGNIFICATION MICROLENSING EVENTS IN 2005–2008 (2010, background): “However, to date only one secure microlensing planet has been discovered from survey-only data, MOA-2007-BLG-192Lb (Bennett et al. 2008).”
• HYDROGEN GREENHOUSE PLANETS BEYOND THE HABITABLE ZONE (2011, background): “…the light curve of an amplified background star, is sensitive to planets with projected separations near the Einstein radius of their host star, e.g. ∼3.5 AU for a solar mass. Surveys have found planets as small as 3M⊕ (Bennett et al. 2008) and projected separations of 0.7-5 AU (Sumi et al. 2010).”
• MOA-2009-BLG-387Lb: a massive planet orbiting an M dwarf (2011, background): “…et al. 2004; Udalski et al. 2005; Beaulieu et al. 2006; Gould et al. 2006; Gaudi et al. 2008; Article published by EDP Sciences A102, page 1 of 16 Bennett et al. 2008; Dong et al. 2009b; Janczak et al. 2010; Sumi et al. 2010), which permits the exploration of host-star and planet populations…”
• Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report (2015, background): “These include the discovery of a substantial population of cold “Super-Earths” (Beaulieu et al. 2006, Bennett et al. 2008, Muraki et al. 2011), the first discovery of a planetary system with an analog to our own Jupiter and Saturn (Gaudi et al. 2008, Bennett et al. 2010), and the detection of a new…”
• TRANSITS OF EARTH-LIKE PLANETS (2009, unknown): “…MEarth and 8.6 MEarth (Udry et al. 2007); HD40307 b, HD40307 c and HD40307 d～4.2, 6.7, and 9.4 MEarth (Mayor et al. 2009); MOA-2007-BLG-192L b ～3.3 MEarth (Bennett et al. 2008); HD 181433 b ～7.6 MEarth (Bouchy et al. 2009); HD 285968 b ～8.4 MEarth (Forveille et al. 2009); HD 7924 b ～9.2 MEarth…”
• THE NIRSPEC ULTRACOOL DWARF RADIAL VELOCITY SURVEY (2010, background): “…orbiting a young brown dwarf in a Doppler survey conducted by Joergens & Müller (2007), a giant planetary companion to 2M1207−39 found by Chauvin et al. (2005) in a direct imaging survey, and a possible super-Earth orbiting the UCD MOA-2007-BLG-192 detected via microlensing (Bennett et al. 2008).”