We combine Spitzer and ground-based observations to measure the microlens parallax vector ${\boldsymbol {\pi }}_{\rm E}$, and thus the mass and distance of OGLE-2014-BLG-0124L, making it the first microlensing planetary system with a space-based parallax measurement. The planet and star have masses of m ~ 0.5 M jup and M ~ 0.7 M ☉ and are separated by a ⊥ ~ 3.1 AU in projection. The main source of uncertainty in all of these numbers (approximately 30%, 30%, and 20%) is the relatively poor measurement of the Einstein radius θE, rather than uncertainty in πE, which is measured with 2.5% precision. This compares to 22% based on OGLE data alone, implying that the Spitzer data provide not only a substantial improvement in the precision of the πE measurement, but also the first independent test of a ground-based ${\boldsymbol {\pi }}_{\rm E}$ measurement.
SPITZERAS A MICROLENS PARALLAX SATELLITE: MASS MEASUREMENT FOR THE OGLE-2014-BLG-0124L PLANET AND ITS HOST STAR
CALCHI NOVATI, Sebastiano;
2015
Abstract
We combine Spitzer and ground-based observations to measure the microlens parallax vector ${\boldsymbol {\pi }}_{\rm E}$, and thus the mass and distance of OGLE-2014-BLG-0124L, making it the first microlensing planetary system with a space-based parallax measurement. The planet and star have masses of m ~ 0.5 M jup and M ~ 0.7 M ☉ and are separated by a ⊥ ~ 3.1 AU in projection. The main source of uncertainty in all of these numbers (approximately 30%, 30%, and 20%) is the relatively poor measurement of the Einstein radius θE, rather than uncertainty in πE, which is measured with 2.5% precision. This compares to 22% based on OGLE data alone, implying that the Spitzer data provide not only a substantial improvement in the precision of the πE measurement, but also the first independent test of a ground-based ${\boldsymbol {\pi }}_{\rm E}$ measurement.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
