University of Tasmania
Browse
apj_785_2_155.pdf (1.34 MB)

MOA-2011-BLG-262Lb: a sub-earth-mass moon orbiting a gas giant primary or a high velocity planetary system in the galactic bulge

Download (1.34 MB)
journal contribution
posted on 2023-05-18, 05:55 authored by Bennett, DP, Batista, V, Bond, IA, Bennett, CS, Suzuki, D, Jean-Philippe BeaulieuJean-Philippe Beaulieu, Udalski, A, Donatowicz, J, Bozza, V, Abe, F, Botzler, CS, Freeman, M, Fukunaga, D, Fukui, A, Itow, Y, Koshimoto, N, Ling, CH, Masuda, K, Matsubara, Y, Muraki, Y, Namba, S, Ohnishi, K, Rattenbury, NJ, Saito, T, Sullivan, DJ, Sumi, T, Sweatman, WL, Tristram, PJ, Tsurumi, N, Wada, K, Yock, PCM, Albrow, MD, Bachelet, E, Brillant, S, Caldwell, JAR, Cassan, A, Andrew ColeAndrew Cole, Corrales, E, Coutures, C, Dieters, S, Dominis Prester, D, Fouque, P, Greenhill, J, Horne, K, Koo, J-R, Kubas, D, Marquette, J-B, Martin, R, Menzies, JW, Sahu, KC, Wambsganss, J, Williams, A, Zub, M, Choi, JY, DePoy, DL, Dong, S, Gaudi, BS, Gould, A, Han, C, Henderson, CB, McGregor, D, Lee, C-U, Pogge, RW, Shin, I-G, Yee, JC, Szymanski, MK, Skowron, J, Poleski, R, Kozlowski, S, Wyrzykowski, L, Kubiak, M, Pietrukowicz, P, Pietrzynski, G, Soszynski, I, Ulaczyk, K, Tsapras, Y, Street, RA, Dominik, M, Bramich, DM, Browne, P, Hundertmark, M, Kains, N, Snodgrass, C, Steele, IA, Dekany, I, Gonzalez, OA, Heyrovsky, D, Kandori, R, Kerins, E, Lucas, PW, Minniti, D, Nagayama, T, Rejkuba, M, Robin, AC, Saito, R
We present the first microlensing candidate for a free-floating exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of Mhost ∼4 Jupiter masses hosting a sub-Earth mass moon. The argument for an exomoon hinges on the system being relatively close to the Sun. The data constrain the product MLπrel where ML is the lens system mass and πrel is the lens-source relative parallax. If the lens system is nearby (large πrel), then ML is small (a few Jupiter masses) and the companion is a sub-Earth-mass exomoon. The best-fit solution has a large lens-source relative proper motion, μrel = 19.6 ± 1.6 mas yr–1, which would rule out a distant lens system unless the source star has an unusually high proper motion. However, data from the OGLE collaboration nearly rule out a high source proper motion, so the exoplanet+exomoon model is the favored interpretation for the best fit model. However, there is an alternate solution that has a lower proper motion and fits the data almost as well. This solution is compatible with a distant (so stellar) host. A Bayesian analysis does not favor the exoplanet+exomoon interpretation, so Occam's razor favors a lens system in the bulge with host and companion masses of Mhost = 0.12+0.19-0.06 M and mcomp = 18+28-10 M, at a projected separation of a = 0.84+0.25-0.14 AU. The existence of this degeneracy is an unlucky accident, so current microlensing experiments are in principle sensitive to exomoons. In some circumstances, it will be possible to definitively establish the mass of such lens systems through the microlensing parallax effect. Future experiments will be sensitive to less extreme exomoons.

History

Publication title

The Astrophysical Journal

Volume

785

Article number

155

Number

155

Pagination

1-13

ISSN

0067-0049

Department/School

School of Natural Sciences

Publisher

Univ Chicago Press

Place of publication

1427 E 60Th St, Chicago, USA, Il, 60637-2954

Rights statement

Copyright 2014 The American Astronomical Society

Repository Status

  • Open

Socio-economic Objectives

Expanding knowledge in the physical sciences

Usage metrics

    University Of Tasmania

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC