Simulation of a Space-based Microlensing Survey for Terrestrial Extrasolar Planets

By D. Bennett, S. Rhie. 2000

162 citations recorded by the source corpus.

We show that a space-based gravitational microlensing survey for terrestrial extrasolar planets is feasible in the near future and could provide a nearly complete picture of the properties of planetary systems in our Galaxy. We present simulations of such a survey using a 1-2 m aperture space telescope with a ~2 deg2 field of view to continuously monitor ~108 Galactic bulge main-sequence stars. The microlensing techniques allow the discovery of low-mass planets with high signal-to-noise ratio, and the space missions that we have studied are sensitive to planets with masses as low as that of Mars. By targeting main-sequence source stars, which can only be resolved from space, the space-based microlensing survey is able to detect enough light from the lens stars to determine the spectral type of one-third of the lens stars with detected planets, including virtually all of the F, G, and K stars, which comprise one-quarter of the event sample. This enables the determination of the planetary masses and separations in physical units as well as the abundance of planets as a function of stellar type and distance from the Galactic center. We show that a space-based microlensing planet search program has its highest sensitivity to planets at orbital separations of 0.7-10 AU, but it will also have significant sensitivity at larger separations and will be able to detect free-floating planets in significant numbers. This complements the planned terrestrial planet transit missions, which are sensitive to terrestrial planets at separations of ≤1 AU. Such a mission should also detect ~50,000 giant planets via transits, and it is, therefore, the only proposed planet detection method that is sensitive to planets at all orbital radii.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/a14a4645bad23f94b5f5d330481727454b47e549

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In Astronomy and Astrophysics

1. J. Winn
2. D. Fabrycky
3. B. Gaudi
4. K. Horne
5. A. Gal-yam
6. K. Ulaczyk
7. S. Mao
8. C. Han

In Instrumentation

1. J. Winn
2. B. Gaudi
3. D. Fabrycky
4. A. Gal-yam
5. A. Udalski
6. R. Pogge
7. S. Dong
8. Annie Robin

Citations in the corpus

• A Jovian-Mass Planet in Microlensing Event OGLE-2005-BLG-071 (2005, background): “Just as themp sin i ambiguity for radial velocity planet detections can be broken if the planet happens to transit its host, so microlensing can yield star and planet masses in special circumstances as well (Bennett & Rhie 2002; Gould et al. 2003).”
• Microlensing Surveys for Exoplanets (2012, background): “These missions could, in principle, be sensitive to all planets with mass "0.1 M ⊕ and separations a " 0.5 AU (Figure 6), including free-floating planets (Bennett & Rhie 2002, Beaulieu et al. 2010, Green et al. 2011).”
• Predictions of the WFIRST Microlensing Survey. I. Bound Planet Detection Rates (2018, methodology): “…for a factor of 2.2 discrepancy in the microlensing detection efficiency of our GULLS simulations and simulations performed by D. Bennett, based on Bennett & Rhie (2002) and updated for simulations of WFIRST (Green et al. 2011); 1.475 was the geometric mean of the relative detection efficiencies…”
• The Occurrence and Architecture of Exoplanetary Systems (2014, background): “An even more prodigious planet discovery rate could be achieved with a space telescope (Bennett & Rhie 2002), such as the 2.4m wide-field infrared telescope currently being planned for both cosmology and exoplanetary science.”
• OGLE 2003-BLG-235/MOA 2003-BLG-53: A Planetary Microlensing Event (2004, unknown): “The power of microlensing is in its ability to acquire statistics on many systems (Bennett & Rhie 2002).”