Bibliographic Details
| Title: |
OGLE-2017-BLG-0373Lb: A Jovian Mass-Ratio Planet Exposes A New Accidental Microlensing Degeneracy |
| Authors: |
Skowron, J., Ryu, Y. -H., Hwang, K. -H., Udalski, A., Mróz, P., Kozłowski, S., Soszyński, I., Pietrukowicz, P., Szymański, M. K., Poleski, R., Ulaczyk, K., Pawlak, M., Rybicki, K., Iwanek, P., Albrow, M. D., Chung, S. -J., Gould, A., Han, C., Jung, Y. K., Shin, I. -G., Shvartzvald, Y., Yee, J. C., Zang, W., Zhu, W., Cha, S. -M., Kim, D. -J., Kim, H. -W., Kim, S. -L., Lee, C. -U., Lee, D. -J., Lee, Y., Park, B. -G., Pogge, R. W. |
| Publication Year: |
2018 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Earth and Planetary Astrophysics |
| More Details: |
We report the discovery of microlensing planet OGLE-2017-BLG-0373Lb. We show that while the planet-host system has an unambiguous microlens topology, there are two geometries within this topology that fit the data equally well, which leads to a factor 2.5 difference in planet-host mass ratio, i.e., $q=1.5\times 10^{-3}$ vs. $q=0.6\times 10^{-3}$. We show that this is an "accidental degeneracy" in the sense that it is due to a gap in the data. We dub it "the caustic-chirality degeneracy". We trace the mathematical origins of this degeneracy, which should enable similar degenerate solutions to be easily located in the future. A Bayesian estimate, based on a Galactic model, yields a host mass $M=0.25^{+0.30}_{-0.15} M_\odot$ at a distance $D_L=5.9^{+1.3}_{-1.95}$ kpc. The lens-source relative proper motion is relatively fast, $\mu=9$ mas/yr, which implies that the host mass and distance can be determined by high-resolution imaging after about 10 years. The same observations could in principle resolve the discrete degeneracy in $q$, but this will be more challenging.
Comment: 24 pages, 7 figures, 3 tables. Accepted for publication in Acta Astronomica. Light curves and callibration data are available on arXiv as Ancillary files and http://www.astrouw.edu.pl/~jskowron/ogle/ob170373/ |
| Document Type: |
Working Paper |
| DOI: |
10.32023/0001-5237/68.1.2 |
| Access URL: |
http://arxiv.org/abs/1802.10067 |
| Accession Number: |
edsarx.1802.10067 |
| Database: |
arXiv |
