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OGLE-2017-BLG-1434Lb: eighth q<1×10-4 mass-ratio microlens planet confirms turnover in planet mass-ratio function

Udalski, A ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.32023/0001-5237/68.1.1
  3. Abstract:
  4. We report the discovery of a cold Super-Earth planet (mp = 4.4 ± 0.5 M) orbiting a lowmass (M = 0.23 ± 0.03 M) M dwarf at projected separation a = 1.18 ± 0.10 a.u., i.e., about 1.9 times the distance the snow line. The system is quite nearby for a microlensing planet, DL = 0.86 ± 0.09 kpc. Indeed, it was the large lens-source relative parallax πrel = 1.0 mas (combined with the low mass M) that gave rise to the large, and thus well-measured, "microlens parallax πE ∞ (πrel/M)1/2 that enabled these precise measurements. OGLE-2017-BLG-1434Lb is the eighth microlensing planet with planet-host mass ratio q < 1×10-4. We apply a new planet-detection sensitivity method, which is a variant of "V/Vmax, to seven of these eight planets to derive the mass-ratio function in this regime. We find dN/dlnq ∞qp, with p = 1.05+0.78 -0.68 which confirms the "turnover" in the mass function found by Suzuki et al. relative to the power law of opposite sign n =-0.93 ± 0.13 at higher mass ratios q > 2× 10-4.We combine our result with that of Suzuki et al. to obtain p = 0.73+0.42-0.34. © 2018 Copernicus Foundation for Polish Astronomy. All rights reserved
  5. Keywords:
  6. Gravitational lensing: micro ; Planetary systems
  7. Source: Acta Astronomica ; Volume 68, Issue 1 , 2018 , Pages 1-42 ; 00015237 (ISSN)
  8. URL: http://acta.astrouw.edu.pl/Vol68/n1/a_68_1_1.html