The Pan-Pacific Planet Search. Vi. Giant Planets Orbiting Hd 86950 and Hd 222076

Wittenmyer, Robert A.; Jones, M. I.; Zhao, Jun; Marshall, J. P.; Butler, R. Paul; Tinney, C. G.; Wang, Liang; Johnson, John Asher

doi:10.3847/1538-3881/153/2/51

Cited by 56 publications

(50 citation statements)

References 77 publications

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“…Typically, the RV jitter is at the level of ∼ 0.5 m/s in dwarfs, ∼ 1.5 m/s in subgiants, ∼ 4 m/s in low-luminosity red giants (ν max close to 100 µHz) , ∼ 7 m/s in red clump stars (ν max close to 40 µHz), and ∼ 15 m/s in high-luminosity red giants (ν max close to 10 µHz). Encouragingly, these values are consistent with observed jitter values for stars in similar evolutionary states (Johnson et al 2010;Jones et al 2013;Wittenmyer et al 2016Wittenmyer et al , 2017.…”

Section: Predicting Rv Jitter From Stellar Parameterssupporting

confidence: 89%

Predicting radial-velocity jitter induced by stellar oscillations based on Kepler data

Jiang

Huber

Bedding

et al. 2018

Monthly Notices of the Royal Astronomical Society: Letters

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Radial-velocity jitter due to intrinsic stellar variability introduces challenges when characterizing exoplanet systems, particularly when studying small (sub-Neptune-sized) planets orbiting solar-type stars. In this Letter we predicted for dwarfs and giants the jitter due to stellar oscillations, which in velocity have much larger amplitudes than noise introduced by granulation. We then fitted the jitter in terms of the following sets of stellar parameters: (1) Luminosity, mass, and effective temperature: the fit returns precisions (i.e., standard deviations of fractional residuals) of 17.9% and 27.1% for dwarfs and giants, respectively. (2) Luminosity, effective temperature, and surface gravity: The precisions are the same as using the previous parameter set.(3) Surface gravity and effective temperature: we obtain a precision of 22.6% for dwarfs and 27.1% for giants. (4): Luminosity and effective temperature: the precision is 47.8% for dwarfs and 27.5% for giants. Our method will be valuable for anticipating the radial-velocity stellar noise level of exoplanet host stars to be found by the T E SS and PL ATO space missions, and thus can be useful for their follow-up spectroscopic observations. We provide publicly available code (https://github.com/Jieyu126/Jitter) to set a prior for the jitter term as a component when modeling the Keplerian orbits of the exoplanets.

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Section: Predicting Rv Jitter From Stellar Parameterssupporting

confidence: 89%

Predicting radial-velocity jitter induced by stellar oscillations based on Kepler data

Jiang

Huber

Bedding

et al. 2018

Monthly Notices of the Royal Astronomical Society: Letters

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“…Firstly, giant planets are generally hard to be formed around metal-poor stars. The RV surveys focusing on evolved stars (Reffert et al 2015, Jones et al 2016and Wittenmyer et al 2017) showed a positive correlation between stellar metallicity and occurrence rate of giant planets, which has been already observed for the cases of main-sequence stars Valenti 2005 andSantos 2007). This is consistent with one of the well-established planet formation scenario, core-accretion model (e.g., Pollack et al 1996).…”

Section: Discussionsupporting

confidence: 71%

“…A role of metallicity in planetary formation and evolution is not well investigated for evolved stars. While Reffert et al (2015), Jones et al (2016) and Wittenmyer et al (2017) showed that metalrich giant stars preferentially host giant planets, Jofré et al (2015) showed that there is no difference in metallicity between giant stars with and without planets. Jofré et al (2015) also showed that the metallicity of evolved stars hosting multiple-planets is slightly enhanced compared with evolved stars hosting single-planet, which was suggested for main-sequence stars (Wright et al 2009).…”

Section: )mentioning

confidence: 99%

Planets around the evolved stars 24 Boötis and γ Libra: A 30 d-period planet and a double giant-planet system in possible 7:3 MMR

Takuya

Sato

Omiya

et al. 2018

Publications of the Astronomical Society of Japan

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We report the detection of planets around two evolved giant stars from radial velocity mea-1 surements at Okayama Astrophysical observatory. 24 Boo (G3IV) has a mass of 0.99 M ⊙ , a radius of 10.64 R ⊙ , and a metallicity of [Fe/H] = −0.77. The star hosts one planet with a minimum mass of 0.91 M Jup and an orbital period of 30.35 d. The planet has one of the shortest orbital periods among those ever found around evolved stars by radial-veloocity methods. The stellar radial velocities show additional periodicity with 150 d, which are probably attributed to stellar activity. The star is one of the lowest-metallicity stars orbited by planets currently known. γ Lib (K0III) is also a metal-poor giant with a mass of 1.47M ⊙ , a radius of 11.1R ⊙ , and [Fe/H] = −0.30. The star hosts two planets with minimum masses of 1.02 M Jup and 4.58 M Jup , and periods of 415 d and 964 d, respectively. The star has the second lowest metallicity among the giant stars hosting more than two planets. Dynamical stability analysis for the γ Lib system sets a minimum orbital inclination angle to be about 70 • and suggests that the planets are in 7:3 mean-motion resonance, though the current best-fitted orbits to the radial-velocity data are not totally regular.

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“…However, while it is clear that stars with properties that deviate vastly from solar should not be used in differential analysis, it is not clear what the cut-off in parameters should be for planet host stars, which are typically FGK dwarfs and subgiants, although planets have also been found around giant stars (e.g. Wittenmyer et al (2017)). In this paper we analyse a set of 23 FGK stars and compare a line list us-ing the laboratory data from VALD with a differential line list in order to investigate if the differential list is really the best one to use and if errors are more likely for stars with parameters furthest from solar.…”

Section: Introductionmentioning

confidence: 99%

The Homogeneous Study of Transiting Systems (HoSTS) – II. The influence of the line list on stellar parameters

Doyle

Smalley

Faedi

et al. 2017

Monthly Notices of the Royal Astronomical Society

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The use of high resolution, high signal-to-noise stellar spectra is essential in order to determine the most accurate and precise stellar atmospheric parameters via spectroscopy. This is particularly important for determining the fundamental parameters of exoplanets, which directly depend on the stellar properties. However, different techniques can be implemented when analysing these spectra which will influence the results. These include performing an abundance analysis relative to the solar values in order to negate uncertainties in atomic data, and fixing the surface gravity (log g) to an external value such as those from asteroseismology. The choice of lines used will also influence the results. In this paper, we investigate differential analysis and fixing log g for a set of FGK stars that already have accurate fundamental parameters known from external methods. We find that a differential line list gives slightly more accurate parameters compared to a laboratory line list, however the laboratory line list still gives robust parameters. We also find that fixing the log g does not improve the spectroscopic parameters. We investigate the effects of line selection on the stellar parameters and find that the choice of lines used can have a significant effect on the parameters. In particular, removal of certain low excitation potential lines can change the T eff by up to 50 K. For future HoSTS papers we will use the differential line list with a solar microturbulence value of 1 km s −1 , and we will not fix the log g to an external value.

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The Pan-Pacific Planet Search. Vi. Giant Planets Orbiting Hd 86950 and Hd 222076

Cited by 56 publications

References 77 publications

Predicting radial-velocity jitter induced by stellar oscillations based on Kepler data

Predicting radial-velocity jitter induced by stellar oscillations based on Kepler data

Planets around the evolved stars 24 Boötis and γ Libra: A 30 d-period planet and a double giant-planet system in possible 7:3 MMR

The Homogeneous Study of Transiting Systems (HoSTS) – II. The influence of the line list on stellar parameters

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