1303.6957 (J. C. Yee)

WFIRST Planet Masses from Microlens Parallax    [PDF]

J. C. Yee

I present a method using only a few ground-based observations of a magnified microlensing event to routinely measure the parallaxes of WFIRST events if WFIRST is in an L2 orbit. This could be achieved with target-of-opportunity observations of select WFIRST events, but is better done with a complementary, ground-based survey of the WFIRST fields. Such a survey would measure the parallax for essentially all events with A_max >~30. When combined with a measurement of the angular size of the Einstein ring, which is almost always measured in events with planets, these parallax measurements will routinely give measurements of the lens masses and hence, the absolute masses of the planets. It can also lead to mass measurements for dark, isolated objects such as brown dwarfs, free-floating planets, and stellar remnants if the size of the Einstein ring can be determined.

View original: http://arxiv.org/abs/1303.6957