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The First Neptune Analog or Super-Earth with Neptune-like Orbit: MOA-2013-BLG-605Lb

Authors :
Sumi, T.
Udalski, A.
Bennett, D. P.
Gould, A.
Poleski, R.
Bond, I. A.
Rattenbury, N.
Pogge, R. W.
Bensby, T.
Beaulieu, J. P.
Marquette, J. B.
Batista, V.
Brillant, S.
Abe, F.
Asakura, Y.
Bhattacharya, A.
Donachie, M.
Freeman, M.
Fukui, A.
Hirao, Y.
Itow, Y.
Koshimoto, N.
Li, M. C. A.
Ling, C. H.
Masuda, K.
Matsubara, Y.
Muraki, Y.
Nagakane, M.
Ohnishi, K.
Oyokawa, H.
Saito, To.
Sharan, A.
Sullivan, D. J.
Suzuki, D.
Tristram, J.
Yonehara, A.
Szymanski, M. K.
Ulaczyk, K.
Kozlowski, S.
Wyrzykowski, L.
Kubiak, M.
Pietrukowicz, P.
Pietrzynski, G.
Soszynski, I.
Han, C.
Jung, Y. -K.
Shin, I. -G
Lee, C-U.
Publication Year :
2015

Abstract

We present the discovery of the first Neptune analog exoplanet or super-Earth with Neptune-like orbit, MOA-2013-BLG-605Lb. This planet has a mass similar to that of Neptune or a super-Earth and it orbits at $9\sim 14$ times the expected position of the snow-line, $a_{\rm snow}$, which is similar to Neptune's separation of $ 11\,a_{\rm snow}$ from the Sun. The planet/host-star mass ratio is $q=(3.6\pm0.7)\times 10^{-4}$ and the projected separation normalized by the Einstein radius is $s=2.39\pm0.05$. There are three degenerate physical solutions and two of these are due to a new type of degeneracy in the microlensing parallax parameters, which we designate "the wide degeneracy". The three models have (i) a Neptune-mass planet with a mass of $M_{\rm p}=21_{-7}^{+6} M_{Earth}$ orbiting a low-mass M-dwarf with a mass of $M_{\rm h}=0.19_{-0.06}^{+0.05} M_\odot$, (ii) a mini-Neptune with $M_{\rm p}= 7.9_{-1.2}^{+1.8} M_{Earth}$ orbiting a brown dwarf host with $M_{\rm h}=0.068_{-0.011}^{+0.019} M_\odot$ and (iii) a super-Earth with $M_{\rm p}= 3.2_{-0.3}^{+0.5} M_{Earth}$ orbiting a low-mass brown dwarf host with $M_{\rm h}=0.025_{-0.004}^{+0.005} M_\odot$ which is slightly favored. The 3-D planet-host separations are 4.6$_{-1.2}^{+4.7}$ AU, 2.1$_{-0.2}^{+1.0}$ AU and 0.94$_{-0.02}^{+0.67}$ AU, which are $8.9_{-1.4}^{+10.5}$, $12_{-1}^{+7}$ or $14_{-1}^{+11}$ times larger than $a_{\rm snow}$ for these models, respectively. The Keck AO observation confirm that the lens is faint. This discovery suggests that low-mass planets with Neptune-like orbit are common. So processes similar to the one that formed Neptune in our own Solar System or cold super-Earth may be common in other solar systems.<br />Comment: 54 pages, 10 figures, 13 tables, Accepted for publication in the ApJ

Details

Database :
arXiv
Publication Type :
Report
Accession number :
edsarx.1512.00134
Document Type :
Working Paper
Full Text :
https://doi.org/10.3847/0004-637X/825/2/112