A Caltech Library Service

The N2K Consortium. VI. Doppler Shifts without Templates and Three New Short-Period Planets

Johnson, John Asher and Marcy, Geoffrey W. and Fischer, Debra A. and Laughlin, Gregory and Butler, R. Paul and Henry, Gregory W. and Valenti, Jeff A. and Ford, Eric B. and Vogt, Steven S. and Wright, Jason T. (2006) The N2K Consortium. VI. Doppler Shifts without Templates and Three New Short-Period Planets. Astrophysical Journal, 647 (1). pp. 600-611. ISSN 0004-637X. doi:10.1086/505173.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


We present a modification to the iodine cell Doppler technique that eliminates the need for an observed stellar template spectrum. For a given target star, we iterate toward a synthetic template spectrum beginning with an existing template of a similar star. We then perturb the shape of this first-guess template to match the program observation of the target star taken through an iodine cell. The elimination of a separate template observation saves valuable telescope time, a feature that is ideally suited for the quick-look strategy employed by the "Next 2000 Stars" (N2K) planet search program. Tests using Keck HIRES (High Resolution Echelle Spectrometer) spectra indicate that synthetic templates yield a short-term precision of 3 m s^(-1) and a long-term, run-to-run precision of 5 m s^(-1). We used this new Doppler technique to discover three new planets: a 1.50M_J planet in a 2.1375 day orbit around HD 86081; a 0.71M_J planet in circular, 26.73 day orbit around HD 224693; and a Saturn-mass planet in an 18.179 day orbit around HD 33283. The remarkably short period of HD 86081b bridges the gap between the extremely short period planets detected in the Optical Gravitational Lensing Experiment (OGLE) survey and the 16 Doppler-detected hot Jupiters (P < 15 days), which have an orbital period distribution that piles up at about 3 days. We have acquired photometric observations of two of the planetary host stars with the automated photometric telescopes at Fairborn Observatory. HD 86081 and HD 224693 both lack detectable brightness variability on their radial velocity periods, supporting planetary-reflex motion as the cause of the radial velocity variability. HD 86081 shows no evidence of planetary transits in spite of a 17.6% transit probability. We have too few photometric observations to detect or rule out transits for HD 224693.

Item Type:Article
Related URLs:
URLURL TypeDescription
Johnson, John Asher0000-0001-9808-7172
Marcy, Geoffrey W.0000-0002-2909-0113
Fischer, Debra A.0000-0003-2221-0861
Laughlin, Gregory0000-0002-3253-2621
Henry, Gregory W.0000-0003-4155-8513
Valenti, Jeff A.0000-0003-3305-6281
Ford, Eric B.0000-0001-6545-639X
Wright, Jason T.0000-0001-6160-5888
Additional Information:© 2006 American Astronomical Society. Received 2006 February 21; accepted 2006 April 14. We would like to thank Ansgar Reiners for his constructive comments and suggestions on our spectral morphing technique. Thanks to Tim Robishaw for lending his expertise in data presentation, and for his many useful IDL Postscript and plotting routines. We gratefully acknowledge the efforts and dedication of the Keck Observatory staff. We thank the NOAO and NASA telescope assignment committees for generous allocations of telescope time. We appreciate funding from NASA grant NNG05GK92G (to G. W. M.) for supporting this research. D. A. F. is a Cottrell Science Scholar of the Research Corporation and acknowledges support from NASA grant NNG05G164G that made this work possible. We also thank NSF for its grants AST-0307493 and AST-9988358 (to S. S. V.). G.W. H. acknowledges support from NASA grant NCC5-511 and NSF grant HRD 97-06268. 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
NSFHRD 97-06268
Issue or Number:1
Record Number:CaltechAUTHORS:20130104-135449158
Persistent URL:
Official Citation:The N2K Consortium. VI. Doppler Shifts without Templates and Three New Short-Period Planets John Asher Johnson et al. 2006 ApJ 647 600
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36181
Deposited By: Ruth Sustaita
Deposited On:04 Jan 2013 22:12
Last Modified:09 Nov 2021 23:20

Repository Staff Only: item control page