Determination of the Astronomical Unit from Hydrogen-Line Radial-Velocity Measurements

AbstractAsteroseismology is among the most powerful observational tools to determine fundamental properties of stars. Space-based photometry has recently enabled the systematic detection of oscillations in exoplanet host stars, allowing a combination of asteroseismology with transit and radial-velocity measurements to characterize planetary systems. In this contribution I will review the key synergies between asteroseismology and exoplanet science such as the precise determination of radii and ages of exoplanet host stars, as well as applications of asteroseismology to measure spin-orbit inclinations in multiplanet systems and orbital eccentricities of small planets. Finally I will give a brief outlook on asteroseismic studies of exoplanet hosts with current and future space-based missions such as K2 and TESS.

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HD 219666 b: a hot-Neptune from TESS Sector 1

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834853 ◽

2019 ◽

Vol 623 ◽

pp. A165 ◽

Cited By ~ 17

Author(s):

M. Esposito ◽

D. J. Armstrong ◽

D. Gandolfi ◽

V. Adibekyan ◽

M. Fridlund ◽

...

Keyword(s):

Radial Velocity ◽

Thermal Structure ◽

Formation Mechanisms ◽

Mass Determination ◽

Velocity Measurements ◽

Fundamental Parameters ◽

Refractory Elements ◽

Rare Class ◽

In Transit

We report on the confirmation and mass determination of a transiting planet orbiting the old and inactive G7 dwarf star HD 219666 (M⋆ = 0.92 ± 0.03 M⊙, R⋆ = 1.03 ± 0.03 R⊙, τ⋆ = 10 ± 2 Gyr). With a mass of Mb = 16.6 ± 1.3 M⊕, a radius of Rb = 4.71 ± 0.17 R⊕, and an orbital period of Porb ≃ 6 days, HD 219666 b is a new member of a rare class of exoplanets: the hot-Neptunes. The Transiting Exoplanet Survey Satellite (TESS) observed HD 219666 (also known as TOI-118) in its Sector 1 and the light curve shows four transit-like events, equally spaced in time. We confirmed the planetary nature of the candidate by gathering precise radial-velocity measurements with the High Accuracy Radial velocity Planet Searcher (HARPS) at ESO 3.6 m. We used the co-added HARPS spectrum to derive the host star fundamental parameters (Teff = 5527 ± 65 K, log g⋆ = 4.40 ± 0.11 (cgs), [Fe/H]= 0.04 ± 0.04 dex, log R′HK = −5.07 ± 0.03), as well as the abundances of many volatile and refractory elements. The host star brightness (V = 9.9) makes it suitable for further characterisation by means of in-transit spectroscopy. The determination of the planet orbital obliquity, along with the atmosphericmetal-to-hydrogen content and thermal structure could provide us with important clues on the formation mechanisms of this class of objects.

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Relationship between the system of Astronomical constants and the radar determinations of the Astronomical Unit

Symposium - International Astronomical Union ◽

10.1017/s0074180900104930 ◽

1965 ◽

Vol 21 ◽

pp. 153-175

Author(s):

D. O. Muhleman

Keyword(s):

Error Analysis ◽

Astronomical Unit ◽

Astronomical Constants

This paper is devoted to an exact discussion of the determination of the astronomical unit with radar and to an extensive error analysis of the technique. Theoretical relationships between the constants are used to construct a consistent set of numerical values of constants based on these results.

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Determination of the Radial Velocity of a Relativistic Star

Nature ◽

10.1038/226737a0 ◽

1970 ◽

Vol 226 (5247) ◽

pp. 737-738 ◽

Cited By ~ 1

Author(s):

A. C. LE FLOCH

Keyword(s):

Radial Velocity ◽

Relativistic Star

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Mass determination of the 1:3:5 near-resonant planets transiting GJ 9827 (K2-135)

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832872 ◽

2018 ◽

Vol 618 ◽

pp. A116 ◽

Cited By ~ 13

Author(s):

J. Prieto-Arranz ◽

E. Palle ◽

D. Gandolfi ◽

O. Barragán ◽

E. W. Guenther ◽

...

Keyword(s):

Planetary System ◽

Initial Conditions ◽

Dynamical Evolution ◽

Space Mission ◽

Mass Determination ◽

Velocity Measurements ◽

Orbital Periods ◽

The Masses ◽

Better Than

Context. Multiplanet systems are excellent laboratories to test planet formation models as all planets are formed under the same initial conditions. In this context, systems transiting bright stars can play a key role, since planetary masses, radii, and bulk densities can be measured. Aims. GJ 9827 (K2-135) has recently been found to host a tightly packed system consisting of three transiting small planets whose orbital periods of 1.2, 3.6, and 6.2 days are near the 1:3:5 ratio. GJ 9827 hosts the nearest planetary system (~30 pc) detected by NASA’s Kepler or K2 space mission. Its brightness (V = 10.35 mag) makes the star an ideal target for detailed studies of the properties of its planets. Methods. Combining the K2 photometry with high-precision radial-velocity measurements gathered with the FIES, HARPS, and HARPS-N spectrographs we revised the system parameters and derive the masses of the three planets. Results. We find that GJ 9827 b has a mass of Mb = 3.69−0.46+0.48 M⊕ and a radius of Rb = 1.58−0.13+0.14 R⊕, yielding a mean density of ρb = 5.11−1.27+1.74 g cm−3. GJ 9827 c has a mass of Mc = 1.45−0.57+0.58 M⊕, radius of Rc = 1.24−0.11+0.11 R⊕, and a mean density of ρc = 4.13−1.77+2.31 g cm−3. For GJ 9827 d, we derive Md = 1.45−0.57+0.58 M⊕, Rd = 1.24−0.11+0.11 R⊕, and ρd = 1.51−0.53+0.71 g cm−3. Conclusions. GJ 9827 is one of the few known transiting planetary systems for which the masses of all planets have been determined with a precision better than 30%. This system is particularly interesting because all three planets are close to the limit between super-Earths and sub-Neptunes. The planetary bulk compositions are compatible with a scenario where all three planets formed with similar core and atmosphere compositions, and we speculate that while GJ 9827 b and GJ 9827 c lost their atmospheric envelopes, GJ 9827 d maintained its primordial atmosphere, owing to the much lower stellarirradiation. This makes GJ 9827 one of the very few systems where the dynamical evolution and the atmosphericescape can be studied in detail for all planets, helping us to understand how compact systems form and evolve.

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Precision stellar radial velocity measurements with FIDEOS at the ESO 1-m telescope of La Silla

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/sty936 ◽

2018 ◽

Vol 477 (4) ◽

pp. 5041-5051 ◽

Cited By ~ 5

Author(s):

L Vanzi ◽

A Zapata ◽

M Flores ◽

R Brahm ◽

M Tala Pinto ◽

...

Keyword(s):

Radial Velocity ◽

Velocity Measurements

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Determination of global kinetic parameters by optimization procedure using burning velocity measurements

Mathematical Modelling of Natural Phenomena ◽

10.1051/mmnp/2018048 ◽

2018 ◽

Vol 13 (6) ◽

pp. 50

Author(s):

Gleb V. Grenkin ◽

Alexander Yu. Chebotarev ◽

Valeri I. Babushok ◽

Sergey S. Minaev

Keyword(s):

Kinetic Parameters ◽

Equivalence Ratio ◽

Reaction Rate ◽

Functional Dependence ◽

Burning Velocity ◽

Optimization Procedure ◽

Optimal Parameters ◽

Velocity Measurements ◽

Equilibrium Calculations

The optimization procedure was developed to derive the global kinetic parameters using experimental dependence of burning velocity on the equivalence ratio. The simple model of laminar premixed flame propagation with assumed constant parameters was used to demonstrate the features of the suggested procedure. The suggested method allows finding optimal parameters for the defined functional dependence of the reaction rate on the temperature and reactant concentrations. The dependence of combustion adiabatic temperature on equivalence ratio is assumed to be known from the flame equilibrium calculations. The global kinetic parameters of combustion reaction were determined for methane, ethylene and propane mixtures with air on the basis of experimental data on burning velocity as function of the equivalence ratio. The calculated overall kinetic parameters are compared with parameters obtained by other methods within similar global model.

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Spectroscopic Orbit of the Eclipsing Binary BD +52°2009

International Astronomical Union Colloquium ◽

10.1017/s0252921100048739 ◽

1999 ◽

Vol 170 ◽

pp. 325-330

Author(s):

B. Khalesseh

Keyword(s):

Correlation Function ◽

Light Curve ◽

Radial Velocity ◽

Physical Model ◽

Cross Correlation ◽

Cross Correlation Function ◽

Physical Parameters ◽

Mass Ratio ◽

Velocity Measurements ◽

Eclipsing Binary

AbstractNew radial velocity measurements of the Algol-type eclipsing binary BD +52 °2009, based on Reticon observations, are presented. The velocity measures are based on fitting theoretical profiles, generated by a physical model of the binary, to the observed cross-correlation function (ccf). Such profiles match this function very well, much better in fact than Gaussian profiles, which are generally used. Measuring the ccf’s with Gaussian profiles yields the following results: mp sin3i = 2.55 ± 0.05m⊙, ms sin3i = 1.14 ± 0.03m⊙, (ap + as) sin i = 7.34 ± 0.05R⊙, and mp/ms = 2.23 ± 0.05. However, measuring the ccf’s with theoretical profiles yields a mass ratio of 2.33 and following results: mp sin3i = 2.84 ± 0.05m⊙, ms sin3i = 1.22 ± 0.03m⊙, (ap + as) sin i = 7.56 ± 0.05R⊙. The system has a semi-detached configuration. By combining the solution of a previously published light curve with the spectroscopic orbit, one can obtain the following physical parameters: mp = 2.99m⊙, ms3 = 1.28m⊙, < Tp >= 9600K, < Ts >= 5400K, < Rp >= 2.35R⊙, < Rs >= 2.12R⊙. The system consists of an A0 primary and a G2 secondary.

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Determination of accurate stellar radial-velocity measures

Astronomy and Astrophysics ◽

10.1051/0004-6361:20020660 ◽

2002 ◽

Vol 390 (1) ◽

pp. 383-395 ◽

Cited By ~ 14

Author(s):

D. Gullberg ◽

L. Lindegren

Keyword(s):

Radial Velocity

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