STELLAR PARAMETERS FOR HD 69830, A NEARBY STAR WITH THREE NEPTUNE MASS PLANETS AND AN ASTEROID BELT

Journal Article · Fri Feb 20 00:00:00 EST 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/800/2/115· OSTI ID:22522101

Tanner, Angelle ^[1]; Boyajian, Tabetha S.; Brewer, John M.; Fischer, Debra ^[2]; Von Braun, Kaspar; Van Belle, Gerard T. ^[3]; Kane, Stephen ^[4]; Farrington, Chris; Brummelaar, Theo A. ten; McAlister, Harold A.; Schaefer, Gail ^[5]; Beichman, Charles A. ^[6]

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1. Mississippi State University, Department of Physics and Astronomy, Hilbun Hall, Starkville, MS 39762 (United States)
2. Department of Astronomy, Yale University, New Haven, CT 06511 (United States)
3. Lowell Observatory, 1400 W. Mars Hill Road, Flagstaff, AZ 86001 (United States)
4. Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132 (United States)
5. Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P.O. Box 4106, Atlanta, GA 30302-4106 (United States)
6. NASA Exoplanet Science Institute, California Institute of Technology, MC 100-22, Pasadena, CA 91125 (United States)

We used the CHARA Array to directly measure the angular diameter of HD 69830, home to three Neptune mass planets and an asteroid belt. Our measurement of 0.674 ± 0.014 mas for the limb-darkened angular diameter of this star leads to a physical radius of R {sub *} = 0.9058 ± 0.0190 R {sub ☉} and luminosity of L {sub *} = 0.622 ± 0.014 L {sub ☉} when combined with a fit to the spectral energy distribution of the star. Placing these observed values on an Hertzsprung-Russel diagram along with stellar evolution isochrones produces an age of 10.6 ± 4 Gyr and mass of 0.863 ± 0.043 M {sub ☉}. We use archival optical echelle spectra of HD 69830 along with an iterative spectral fitting technique to measure the iron abundance ([Fe/H] = –0.04 ± 0.03), effective temperature (5385 ± 44 K), and surface gravity (log g = 4.49 ± 0.06). We use these new values for the temperature and luminosity to calculate a more precise age of 7.5 ± 3 Gyr. Applying the values of stellar luminosity and radius to recent models on the optimistic location of the habitable zone produces a range of 0.61-1.44 AU; partially outside the orbit of the furthest known planet (d) around HD 69830. Finally, we estimate the snow line at a distance of 1.95 ± 0.19 AU, which is outside the orbit of all three planets and its asteroid belt.

• OSTI ID: 22522101
• Journal Information: Astrophysical Journal, Vol. 800, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTEROIDS
DIAGRAMS
ELEMENT ABUNDANCE
ENERGY SPECTRA
GRAVITATION
HYDROGEN
IRON
ITERATIVE METHODS
LUMINOSITY
MASS
NEPTUNE PLANET
ORBITS
SNOW
STAR EVOLUTION
STARS