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Five New Multicomponent Planetary Systems

Vogt, Steven S. and Butler, R. Paul and Marcy, Geoffrey W. and Fischer, Debra A. and Henry, Gregory W. and Laughlin, Greg and Wright, Jason T. and Johnson, John A. (2005) Five New Multicomponent Planetary Systems. Astrophysical Journal, 632 (1). pp. 638-658. ISSN 0004-637X. doi:10.1086/432901.

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We report Doppler measurements for six nearby G- and K-type main-sequence stars that show multiple low-mass companions, at least one of which has planetary mass. One system has three planets, the fourth triple-planet system known around a normal star, and another has an extremely low minimum mass of 18 M_⊕. HD 128311 (K0 V) has two planets (one previously known) with minimum masses (M sin i) of 2.18M_J and 3.21M_J and orbital periods of 1.26 and 2.54 yr, suggesting a possible 2 : 1 resonance. For HD 108874 (G5 V), the velocities reveal two planets (one previously known) having minimum masses and periods of (M sin i_b = 1.36M_J, P_b = 1.08 yr) and (M sin i_c = 1.02M_J, P_c = 4.4 yr). HD 50499 (G1 V) has a planet with P = 6.8 yr and M sin i = 1.7M_J, and the velocity residuals exhibit a trend of -4.8 m s^(-1) yr^(-1), indicating a more distant companion with P > 10 yr and minimum mass of 2M_J. HD 37124 (G4 IV-V) has three planets, one having M sin i = 0.61M_J and P = 154.5 days, as previously known. We find two plausible triple-planet models that fit the data, both having a second planet near P = 840 days, with the more likely model having its third planet in a 6 yr orbit and the other one in a 29 day orbit. For HD 190360, we confirm the planet having P = 7.9 yr and M sin i = 1.5M_J as found by the Geneva team, but we find a distinctly noncircular orbit with e = 0.36 ± 0.03, rendering this not an analog of Jupiter as had been reported. Our velocities also reveal a second planet with P = 17.1 days and M sin i = 18.1 M_⊕. HD 217107 (G8 IV) has a previously known "hot Jupiter" with M sin i = 1.4M_J and P = 7.13 days, and we confirm its high eccentricity, e = 0.13. The velocity residuals reveal an outer companion in an eccentric orbit, having minimum mass of M sin i > 2M_J, eccentricity e ~ 0.5, and a period P > 8 yr, implying a semimajor axis α > 4 AU and providing an opportunity for direct detection. We have obtained high-precision photometry of five of the six planetary host stars with three of the automated telescopes at Fairborn Observatory. We can rule out significant brightness variations in phase with the radial velocities in most cases, thus supporting planetary reflex motion as the cause of the velocity variations. Transits are ruled out to very shallow limits for HD 217107 and are also shown to be unlikely for the prospective inner planets of the HD 37124 and HD 108874 systems. HD 128311 is photometrically variable with an amplitude of 0.03 mag and a period of 11.53 days, which is much shorter than the orbital periods of its two planetary companions. This rotation period explains the origin of periodic velocity residuals to the two-planet model of this star. All of the planetary systems here would be further constrained with astrometry by the Space Interferometry Mission.

Item Type:Article
Related URLs:
URLURL TypeDescription
Marcy, Geoffrey W.0000-0002-2909-0113
Fischer, Debra A.0000-0003-2221-0861
Henry, Gregory W.0000-0003-4155-8513
Laughlin, Greg0000-0002-3253-2621
Wright, Jason T.0000-0001-6160-5888
Johnson, John A.0000-0001-9808-7172
Additional Information:© 2005 American Astronomical Society. Received 2005 January 20; accepted 2005 June 22. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time has been granted by both NASA and the University of California. We thank A. Cumming, E. Ford, and Kevin Apps for valuable discussions. We thank Mike Liu for adaptive optics images of target stars. We gratefully acknowledge the efforts and dedication of the Keck Observatory staff. We also thank Lou Boyd for his ongoing support of Fairborn Observatory. We appreciate support by NASA grant NAG5-75005 and by NSF grants AST 03-07493 and AST 99-88087 (to S. S. V. ), by NASA grant NAG5-12182, and travel support from the Carnegie Institution of Washington (to R. P. B.). G. W. H. acknowledges support from NASA grant NCC5-511 and NSF grant HRD-9706268. We are also grateful for support by Sun Microsystems. We thank the NASA and UC Telescope assignment committees for allocations of telescope time. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France. The authors wish to extend special thanks to those of Hawaiian ancestry on whose sacred mountain of Mauna Kea we are privileged to be guests. Without their generous hospitality, the Keck observations presented herein would not have been possible.
Funding AgencyGrant Number
NSFAST 03-07493
NSFAST 99-88087
Sun MicrosystemsUNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20130108-151615622
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Official Citation:Five New Multicomponent Planetary Systems Steven S. Vogt et al. 2005 ApJ 632 638
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36250
Deposited By: Ruth Sustaita
Deposited On:08 Jan 2013 23:43
Last Modified:09 Nov 2021 23:21

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