Two planets orbiting the recently formed post-common envelope binary NN Serpentis
Beuermann, K. (Klaus), Hessman, F. V., Dreizler, S., Marsh, T. R., Parsons, S. G., Winget, Donald Earl, 1955-, Miller, G. F., Schreiber, Matthias R., Kley, W., Dhillon, V. S., Littlefair, S. P., Copperwheat, C. M. and Hermes, J. J.. (2010) Two planets orbiting the recently formed post-common envelope binary NN Serpentis. Astronomy & Astrophysics, Vol.521 . L60. ISSN 0004-6361Full text not available from this repository.
Official URL: http://dx.doi.org/10.1051/0004-6361/201015472
Planets orbiting post-common envelope binaries provide fundamental information on planet formation and evolution. We searched for such planets in NN Ser ab, an eclipsing short-period binary that shows long-term eclipse time variations. Using published, reanalysed, and new mid-eclipse times of NN Ser ab obtained between 1988 and 2010, we find excellent agreement with the light-travel-time effect produced by two additional bodies superposed on the linear ephemeris of the binary. Our multi-parameter fits accompanied by N-body simulations yield a best fit for the objects NN Ser (ab)c and d locked in the 2:1 mean motion resonance, with orbital periods P-c similar or equal to 15.5 yrs and P-d similar or equal to 7.7 yrs, masses M-c sin i(c) similar or equal to 6.9 M-Jup and M-d sin i(d) similar or equal to 2.2 M-Jup, and eccentricities e(c) similar or equal to 0 and e(d) similar or equal to 0.20. A secondary chi(2) minimum corresponds to an alternative solution with a period ratio of 5:2. We estimate that the progenitor binary consisted of an A star with similar or equal to 2 M-circle dot and the present M dwarf secondary at an orbital separation of similar to 1.5 AU. The survival of two planets through the common-envelope phase that created the present white dwarf requires fine tuning between the gravitational force and the drag force experienced by them in the expanding envelope. The alternative is a second-generation origin in a circumbinary disk created at the end of this phase. In that case, the planets would be extremely young with ages not exceeding the cooling age of the white dwarf of 10(6) yrs.
|Item Type:||Journal Article|
|Subjects:||Q Science > QB Astronomy|
|Divisions:||Faculty of Science > Physics|
|Journal or Publication Title:||Astronomy & Astrophysics|
|Official Date:||October 2010|
|Number of Pages:||5|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||Alfried Krupp von Bohlen und Halbach-Stiftung, Science and Technology Facilities Council (Great Britain) (STFC), Fondo Nacional de Desarrollo Científico y Tecnológico (Chile) (FONDECYT), Universidad de Valparaíso. Centro de Astrofísica, Texas Higher Education Coordinating Board (THECB), European Southern Observatory (ESO)|
|Grant number:||085.D-0541 (ESO), 1061199 (FONDECYT), 003658-0255-2007 (THECB)|
Alexander, M. E., Chau, W. Y., & Henriksen, R. N. 1976, ApJ, 204, 879
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