Issue |
A&A
Volume 585, January 2016
|
|
---|---|---|
Article Number | A62 | |
Number of page(s) | 5 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/201527380 | |
Published online | 17 December 2015 |
Microlensing planet detection via geosynchronous and low Earth orbit satellites
Sorbonne Universités, UPMC Paris 6 et CNRS, UMR 7095, Institut
d’Astrophysique de Paris,
98bis bd Arago,
75014
Paris,
France
e-mail: mogavero@iap.fr; beaulieu@iap.fr
Received: 16 September 2015
Accepted: 16 October 2015
Planet detection through microlensing is usually limited by a well-known degeneracy in the Einstein timescale tE, which prevents mass and distance of the lens to be univocally determined. It has been shown that a satellite in geosynchronous orbit could provide masses and distances for most standard planetary events (tE ≈ 20 days) via a microlens parallax measurement. This paper extends the analysis to shorter Einstein timescales, tE ≈ 1 day, when dealing with the case of Jupiter-mass lenses. We then study the capabilities of a low Earth orbit satellite on even shorter timescales, tE ≈ 0.1 days. A Fisher matrix analysis is employed to predict how the 1-σ error on parallax depends on tE and the peak magnification of the microlensing event. It is shown that a geosynchronous satellite could detect parallaxes for Jupiter-mass free floaters and discover planetary systems around very low-mass brown dwarfs. Moreover, a low Earth orbit satellite could lead to the discovery of Earth-mass free-floating planets. Limitations to these results can be the strong requirements on the photometry, the effects of blending, and in the case of the low orbit, the Earth’s umbra.
Key words: gravitational lensing: micro / parallaxes / planets and satellites: detection / brown dwarfs
© ESO, 2015
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