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Full-Text Articles in Physical Sciences and Mathematics
A False Planet Around Hd 192263, Gregory W. Henry, Robert A. Donahue, Sallie L. Baliunas
A False Planet Around Hd 192263, Gregory W. Henry, Robert A. Donahue, Sallie L. Baliunas
Information Systems and Engineering Management Research Publications
We present new high-precision Strömgren photometry and Ca II H and K spectrophotometry of HD 192263. Based on radial velocity variations detected previously by two groups, this K2 V star was thought to host a 0.75 MJup (minimum mass) planetary companion in a 24 day orbit. Our photometric observations reveal periodic variations that match the purported planetary orbital period, while the Ca II H and K emission fluxes are modulated on half the planetary period. This suggests that rotational modulation of the visibility of stellar surface activity is the source of the observed radial velocity variations. Therefore, HD 192263 should …
No Planet For Hd 166435, Didier Queloz, Gregory W. Henry, Jean-Pierre Sivan, Sallie L. Baliunas, Jean-Luc Beuzit, Robert A. Donahue, Michel Mayor, Dominique Naef, Christian Perrier, Stephane Udry
No Planet For Hd 166435, Didier Queloz, Gregory W. Henry, Jean-Pierre Sivan, Sallie L. Baliunas, Jean-Luc Beuzit, Robert A. Donahue, Michel Mayor, Dominique Naef, Christian Perrier, Stephane Udry
Information Systems and Engineering Management Research Publications
The G0 V star HD 166435 has been observed by the fiber-fed spectrograph ELODIE as one of the targets in the large extra-solar planet survey that we are conducting at the Observatory of Haute-Provence. We detected coherent, low-amplitude, radial-velocity variations with a period of 3.7987 days, suggesting a possible close-in planetary companion. Subsequently, we initiated a series of high-precision photometric observations to search for possible planetary transits and an additional series of Ca II H and K observations to measure the level of surface magnetic activity and to look for possible rotational modulation. Surprisingly, we found the star to be …
First Results From The Anglo-Australian Planet Search: A Brown Dwarf Candidate And A 51 Peg-Like Planet, Chris G. Tinney, R. Paul Butler, Geoffrey W. Marcy, Hugh R. A. Jones, Alan J. Penny, Steve S. Vogt, Kevin Apps, Gregory W. Henry
First Results From The Anglo-Australian Planet Search: A Brown Dwarf Candidate And A 51 Peg-Like Planet, Chris G. Tinney, R. Paul Butler, Geoffrey W. Marcy, Hugh R. A. Jones, Alan J. Penny, Steve S. Vogt, Kevin Apps, Gregory W. Henry
Information Systems and Engineering Management Research Publications
We report results from the Anglo-Australian Planet Search, a survey for planets around 200 solar-type stars in the southern hemisphere that is being carried out on the 3.9 m Anglo-Australian Telescope. Limiting Doppler precisions of 3 m s-1 have been demonstrated from the first 2.5 years of operation, making this the highest-precision planet search in the southern hemisphere. From these data we report results for two new substellar detections. The first is a 51 Peg-like planet around the star HD 179949 with M sin i = 0.84 MJUP. Photometric study reveals this is not a transiting system. The second is …
Spectroscopy And Photometry Of Nearby Young Solar Analogs, Eric J. Gaidos, Gregory W. Henry, Stephen M. Henry
Spectroscopy And Photometry Of Nearby Young Solar Analogs, Eric J. Gaidos, Gregory W. Henry, Stephen M. Henry
Information Systems and Engineering Management Research Publications
We present new photometry and spectroscopy of 34 stars from a catalog of 38 nearby (d < 25 pc) G and K dwarfs selected as analogs to the early Sun. We report that the least active star in our sample is also slowly rotating and probably of solar age. Two other stars appear to be evolved objects that have recently acquired angular momentum. A fourth star may be a spectroscopic binary. Many of the other stars belong to previously identified common proper-motion groups. Space motions, lithium abundances, and Ca II emission of these stars suggest ages between 70 and 800 Myr.
Search For Transits Of A Short-Period, Sub-Saturn Extrasolar Planet Orbiting Hd 46375, Gregory W. Henry
Search For Transits Of A Short-Period, Sub-Saturn Extrasolar Planet Orbiting Hd 46375, Gregory W. Henry
Information Systems and Engineering Management Research Publications
Precise brightness measurements of HD 46375 have been acquired with an automatic telescope to search for transits of its short-period, sub-Saturn extrasolar planet. Transits of the companion do not occur, indicating that the inclination of the orbit i is less than 83° and sin i is less than 0.992. This upper limit on sin i still preserves the possibility that the mass of the planet is less than Saturn's. Analysis of the photometry for HD 46375 reveals no photometric variability larger than 0.0001 ± 0.0002 mag at the orbital period of the planet. This effectively eliminates starspots and stellar pulsations …
Photometric And Ca Ii H And K Spectroscopic Variations In Nearby Sun-Like Stars With Planets. Iii., Gregory W. Henry, Sallie L. Baliunas, Robert A. Donahue, Francis C. Fekel, Willie Soon
Photometric And Ca Ii H And K Spectroscopic Variations In Nearby Sun-Like Stars With Planets. Iii., Gregory W. Henry, Sallie L. Baliunas, Robert A. Donahue, Francis C. Fekel, Willie Soon
Information Systems and Engineering Management Research Publications
We present the results of an analysis of time-series photometry, Ca II H and K spectrophotometry, and high-dispersion visible spectra of nine nearby Sun-like stars recently identified as having planets. For the six stars whose presumed planets have orbital periods of less than 4 months (τ Boo, 51 Peg, υ And, ρ1 Cnc, ρ CrB, and 70 Vir), sine-curve fits to the photometric data show no variations with semiamplitude greater than 1 or 2 parts in 104. Photometric variations in 47 UMa are similarly small, although our photometric data of this star are slightly affected by variability …
Planetary Companions To The Metal-Rich Stars Bd -10°3166 And Hd 52265, R. Paul Butler, Steve Vogt, Geoffrey W. Marcy, Debra A. Fischer, Gregory W. Henry, Kevin Apps
Planetary Companions To The Metal-Rich Stars Bd -10°3166 And Hd 52265, R. Paul Butler, Steve Vogt, Geoffrey W. Marcy, Debra A. Fischer, Gregory W. Henry, Kevin Apps
Information Systems and Engineering Management Research Publications
Precise Doppler measurements from the Keck/HIRES spectrometer reveal periodic Keplerian velocity variations in the stars BD -10°3166 and HD 52265. BD -10°3166 (K0 V) has a period of 3.487 days and a semiamplitude of 61 m s-1. An orbital fit yields a companion mass M sin i = 0.48 MJUP, a semimajor axis of a = 0.046 AU, and an eccentricity of e = 0.05 (consistent with zero). HD 52265 (G0 V) has a period of 119.0 days, a semiamplitude of 45 m s-1, an eccentricity of 0.29, a semimajor axis of a = …
A Transiting "51 Peg-Like" Planet, Gregory W. Henry, Geoffrey W. Marcy, R. Paul Butler, Steve Vogt
A Transiting "51 Peg-Like" Planet, Gregory W. Henry, Geoffrey W. Marcy, R. Paul Butler, Steve Vogt
Information Systems and Engineering Management Research Publications
Doppler measurements from Keck exhibit a sinusoidal periodicity in the velocities of the G0 dwarf HD 209458, having a semiamplitude of 81 m s-1 and a period of 3.5239 days, which is indicative of a "51 Peg-like" planet with a minimum mass (M sin i) of 0.62 MJup and a semimajor axis of 0.046 AU. Follow-up photometry reveals a drop of 0.017 mag at the predicted time (within the errors) of transit by the companion based on the velocities. This is the first extrasolar planet observed to transit its star. The radius of the planet derived …
Properties Of Sun-Like Stars With Planets: 51 Pegasi, 47 Ursae Majoris, 70 Virginis, And Hd 114762, Gregory W. Henry, Sallie L. Baliunas, Robert A. Donahue, Willie H. Soon, Steven H. Saar
Properties Of Sun-Like Stars With Planets: 51 Pegasi, 47 Ursae Majoris, 70 Virginis, And Hd 114762, Gregory W. Henry, Sallie L. Baliunas, Robert A. Donahue, Willie H. Soon, Steven H. Saar
Information Systems and Engineering Management Research Publications
Radial velocity variations have revealed planets orbiting 51 Peg, 47 UMa, and 70 Vir, and a low-mass companion orbiting HD 114762. We analyze parallel records of photometric measurements in Strömgren b and y and Johnson V, R, and I passbands and Ca II H and K fluxes in those stars. In the case of 51 Peg, the high precision of the differential photometric measurements made by the 0.75 m Automatic Photoelectric Telescope and the nonvariability of the star would allow the detection of a transit of a planet as small as Earth (corresponding to an amplitude of 0.0001 mag) if …
Properties Of Sun-Like Stars With Planets: Ρ1 Cancri, Τ Bootis, And Υ Andromedae, Sallie L. Baliunas, Gregory W. Henry, Robert A. Donahue, Francis C. Fekel, Willie Soon
Properties Of Sun-Like Stars With Planets: Ρ1 Cancri, Τ Bootis, And Υ Andromedae, Sallie L. Baliunas, Gregory W. Henry, Robert A. Donahue, Francis C. Fekel, Willie Soon
Information Systems and Engineering Management Research Publications
Planets have been reported orbiting the Sun-like stars ρ1 Cnc, τ Boo, and υ And based on low-amplitude radial velocity variations. We have derived information on the first two stars from analysis of spectra, as well as parallel records of high-precision Strömgren b and y photometry and Ca II H + K fluxes. In the case of ρ1 Cnc, the upper limit (peak to peak) of nondetection of photometric variability at the orbital period is Δy ~ 0.0004 mag. The possibility of a planetary transit cannot be ruled out completely from the photometric data. Variations of the …