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Tidal Evolution of the Planetary System around HD 83443

Wu, Yanqin and Goldreich, Peter (2002) Tidal Evolution of the Planetary System around HD 83443. Astrophysical Journal, 564 (2). pp. 1024-1027. ISSN 0004-637X. doi:10.1086/324193.

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Two planets with an orbital period ratio of approximately 10:1 have been discovered around the star HD 83443. The inner and more massive planet, HD 83443b, has the smallest semimajor axis among all currently known exoplanets. Unlike other short-period exoplanets, it maintains a substantial orbital eccentricity, e_1 = 0.079 ± 0.008, in spite of efficient tidal damping. This is a consequence of its secular interactions with HD 83443_c, whose orbital eccentricity e_2 = 0.42 ± 0.06. Dissipation, associated with tides the star raises in the inner planet, removes energy but not angular momentum from its orbit, while secular interactions transfer angular momentum but not energy from the inner to the outer planet's orbit. The outward transfer of angular momentum decreases the tidal decay rate of the inner planet's orbital eccentricity while increasing that of the outer planet. The alignment of the apsides of the planets' orbits is another consequence of tidal and secular interactions. In this state the ratio of their orbital eccentricities, e_1/e_2, depends on the secular perturbations the planets exert on each other and on additional perturbations that enhance the inner planet's precession rate. Tidal and rotational distortions of the inner planet along with general relativity provide the most important of these extra precessional perturbations, each of which acts to reduce e_1/e_2. Provided the planets' orbits are coplanar, the observed eccentricity ratio uniquely relates sin i and C ≡ (k_2/k_(2J))(R_1/R_J)^5, where the tidal Love number, k_2, and radius, R_1, of the inner planet are scaled by their Jovian equivalents.

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Additional Information:© 2002 American Astronomical Society. Received 2001 August 8; accepted 2001 September 5. This research was initiated while Y. W. participated in a CITA-ITP postdoctoral exchange program funded by NSF grant PHY 99-07949. She thanks Man-Hoi Lee, Stan Peale, and Brad Hansen for helpful discussions. P. G.Ïs research is supported by NSF grant AST 00-98301.
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NSFPHY 99-07949
NSFAST 00-98301
Issue or Number:2
Record Number:CaltechAUTHORS:20130227-101423922
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Official Citation:Tidal Evolution of the Planetary System around HD 83443 Yanqin Wu and Peter Goldreich 2002 ApJ 564 1024
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37170
Deposited By: Ruth Sustaita
Deposited On:27 Feb 2013 22:10
Last Modified:09 Nov 2021 23:27

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