A COLD NEPTUNE-MASS PLANET OGLE-2007-BLG-368Lb: Cold neptunes are common

By T. Sumi, D. Bennett, I. Bond, A. Udalski, V. Batista, Martin Dominik, P. Fouqué, D. Kubas, A. Gould, Bruce Macintosh and 93 more. 2009

182 citations recorded by the source corpus.

We present the discovery of a Neptune-mass planet OGLE-2007-BLG-368Lb with a planet–star mass ratio of q = [9.5 ± 2.1] × 10−5 via gravitational microlensing. The planetary deviation was detected in real-time thanks to the high cadence of the Microlensing Observations in Astrophysics survey, real-time light-curve monitoring and intensive follow-up observations. A Bayesian analysis returns the stellar mass and distance at Ml = 0.64+0.21−0.26 M☉ and Dl = 5.9+0.9−1.4 kpc, respectively, so the mass and separation of the planet are Mp = 20+7−8 M⊕ and a = 3.3+1.4−0.8 AU, respectively. This discovery adds another cold Neptune-mass planet to the planetary sample discovered by microlensing, which now comprises four cold Neptune/super-Earths, five gas giant planets, and another sub-Saturn mass planet whose nature is unclear. The discovery of these 10 cold exoplanets by the microlensing method implies that the mass ratio function of cold exoplanets scales as dNpl/dlog q ∝ q−0.7±0.2 with a 95% confidence level upper limit of n < −0.35 (where dNpl/dlog q ∝ qn). As microlensing is most sensitive to planets beyond the snow-line, this implies that Neptune-mass planets are at least three times more common than Jupiters in this region at the 95% confidence level.

Subfields: Ecology, Evolution, Behavior and Systematics, Molecular Biology, Plant Science

View Paper: https://www.semanticscholar.org/paper/30760daf5271b7419280c598a7e34b57569cf920

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Citations in the corpus

• Detection of a transit of the super-Earth 55 Cancri e with warm Spitzer (2011, background): “Radial velocity (RV), microlensing and transit surveys have revealed the existence in our Galaxy of a large population of planets with a mass of a few to ∼20 Earth masses (Lovis et al. 2009; Sumi et al. 2010; Borucki et al. 2011).”
• MOA-2009-BLG-387Lb: a massive planet orbiting an M dwarf (2011, methodology): “…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 whose mass and distance are not probed by any other method.”
• FREQUENCY OF SOLAR-LIKE SYSTEMS AND OF ICE AND GAS GIANTS BEYOND THE SNOW LINE FROM HIGH-MAGNIFICATION MICROLENSING EVENTS IN 2005–2008 (2010, methodology): “For n = −0.68 (Sumi et al. 2010), it is 1.0, whereas for n = −0.31 2 Just as RV measurements respond to a projected stellar velocities, and so measure m sin i of the planet which is always less than or equal to the planet mass m, so microlensing observations measure the projected separation s,…”
• The Habitability of Planets Orbiting M-dwarf Stars (2016, background): “However, the planetary mass function inferred from microlensing surveys declines steeply for smaller planets (Sumi et al., 2010).”
• Microlensing Surveys for Exoplanets (2012, methodology): “By adopting a simple model for the scaling of the detection efficiency with q, Sumi et al. (2010) used the distribution of mass ratios of the 10 microlensing planets discovered up to that point to derive an intrinsic mass (ratio) function of exoplanets beyond the snow line of dN /dq ∝ q−1.68±0.20.”
• TESTING IN SITU ASSEMBLY WITH THE KEPLER PLANET CANDIDATE SAMPLE (2013, background): “…but planets in the Uranus/Neptune mass range (10–100 M⊕) have also been found with a range of semimajor axes, both close in (Howard et al. 2010; Mayor et al. 2011; Borucki et al. 2010; Holman et al. 2010; Lissauer et al. 2011a) and at large separations (Gould et al. 2006, 2010; Sumi et al. 2010).”
• THE ROLE OF MULTIPLICITY IN DISK EVOLUTION AND PLANET FORMATION (2011, background): “This hypothesis is supported by the high planet frequency recently reported from microlensing results by Sumi et al. (2010), who suggest that in the separation range most sensitively probed by microlensing (∼2–6 AU), the mass function is sufficiently steep (dN/d log(q) ∝ q−0.7±0.2 that Neptune-mass…”
• 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).”