HD 69830

HD 69830

HD 69830 is a G8V class star less massive than the Sun (G2V)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Puppis
Right ascension 08h 18m 23.94706s[1]
Declination −12° 37′ 55.8116″[1]
Apparent magnitude (V) +5.98[2]
Characteristics
Spectral type G8V[3]
U−B color index 0.33[2]
B−V color index 0.75[2]
V−R color index 0.40
R−I color index 0.36
Variable type none
Astrometry
Radial velocity (Rv)+30.4[4] km/s
Proper motion (μ) RA: 278.99 ± 0.25[1] mas/yr
Dec.: −987.59 ± 0.29[1] mas/yr
Parallax (π)80.04 ± 0.35[1] mas
Distance40.7 ± 0.2 ly
(12.49 ± 0.05 pc)
Absolute magnitude (MV)5.47 ± 0.01[5]
Details
Mass0.863 ± 0.043[3] M☉
Radius0.905 ± 0.019[3] R☉
Luminosity0.622 ± 0.014[3] L☉
Surface gravity (log g)4.53[6] cgs
Temperature5,394 ± 62[3] K
Metallicity [Fe/H]−0.04 ± 0.03[3] dex
Rotation35.1 ± 0.8 days[7]
Rotational velocity (v sin i)0.8±0.5[3] km/s
Age10.6 ± 4[3] Gyr
Other designations
285 G. Puppis,[8] BD−12°2449, GJ 302, HIP 40693, HR 3259, LHS 245, SAO 154093[9]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata
Extrasolar Planets
Encyclopaedia		data

HD 69830 (285 G. Puppis) is a yellow dwarf star located approximately 41 light-years away in the constellation of Puppis. In 2005, the Spitzer Space Telescope discovered a narrow ring of warm debris orbiting the star.[10] The debris ring contains substantially more dust than the Solar System's asteroid belt. In 2006, three extrasolar planets with minimum masses comparable to Neptune were confirmed in orbit around the star, located interior to the debris ring.[11]

Distance and visibility

HD 69830 is a main sequence star of spectral type G8V. It has about 86% of the Sun's mass, 90% of its radius, 62% of its luminosity, and 89% of its iron abundance. The star's age has been estimated at about 10.6 ± 4 billion years. HD 69830 is located about 40.7 light-years from the Sun, lying in the northeastern part of the constellation of Puppis (the Poop Deck). It can be seen east of Sirius, southwest of Procyon, northeast of Delta Canis Majoris, and north of Zeta Puppis.

Planetary system

The HD 69830 planetary system[11][12]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 10.2 M⊕ 0.0785 8.667 ± 0.003 0.1 ± 0.04 — —
c 11.8 M⊕ 0.186 31.56 ± 0.04 0.13 ± 0.06 — —
d 18.1 M⊕ 0.63 197 ± 3 0.07 ± 0.07 — ~4 R⊕
Asteroid belt 0.93–1.16 AU — —

Planets

On May 17, 2006, a team of astronomers using the European Southern Observatory's (ESO) HARPS spectrograph on the 3.6-metre La Silla telescope in the Atacama desert, Chile, announced the discovery of three extrasolar planets orbiting the star. With minimum masses between 10 and 18 times that of the Earth, all three planets are presumed to be similar to the planets Neptune or Uranus. As of 2011, no planet with more than half the mass of Jupiter had been detected within three astronomical units of HD 69830.

The star rotates at an inclination of 13+27
−13 degrees relative to Earth.[7] It has been assumed that the planets share that inclination.[13] However b and c are "hot Neptunes", and outside this system several are now known to be oblique relative to the stellar axis.[14]

The outermost planet discovered appears to be within the system's habitable zone, where liquid water would remain stable (more accurate data on the primary star's luminosity will be required to know for sure where the habitable zone is). HD 69830 is the first extrasolar planetary system around a Sun-like star without any known planets comparable to Jupiter or Saturn in mass.

Debris disk

In 2005, the Spitzer Space Telescope detected a debris disk in the HD 69830 system consistent with being produced by an asteroid belt twenty times more massive than that in our own system. The belt was originally thought to be located inside an orbit equivalent to that of Venus in the Solar System, which would place it between the orbits of the second and third planets. The disk contains sufficient quantities of dust that the nights on any nearby planets would be lit up by zodiacal light 1000 times brighter than that seen on Earth, easily outshining the Milky Way.

Further analysis of the spectrum of the dust revealed that it is composed of highly processed material, likely derived from a disrupted C-type asteroid of at least 30 km radius which contained many small olivine-rich (rocky) and once-wet grains which would not survive at close distances to the star. Instead, it seems more likely that the asteroid belt producing the dust is located outside the orbit of the outermost planet, around 1 AU from the star. This region contains the 2:1 and 5:2 mean motion resonances with HD 69830 d.[12]

See also

References

  1. 1 2 3 4 5 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
  2. 1 2 3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV data. SIMBAD, Bibcode:1986EgUBV........0M.
  3. 1 2 3 4 5 6 7 8 Tanner, Angelle; et al. (February 2015), "Stellar Parameters for HD 69830, a Nearby Star with Three Neptune Mass Planets and an Asteroid Belt", The Astrophysical Journal, 800 (2): 5, arXiv:1412.5251, Bibcode:2015ApJ...800..115T, doi:10.1088/0004-637X/800/2/115, 115.
  4. ↑ Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick. Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. Determination of Radial Velocities and their Applications. 30. University of Toronto: International Astronomical Union. p. 57. Bibcode:1967IAUS...30...57E.
  5. ↑ Holmberg, J.; et al. (2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics. 501 (3): 941–947. arXiv:0811.3982. Bibcode:2009A&A...501..941H. doi:10.1051/0004-6361/200811191. Vizier catalog entry
  6. ↑ Ramírez, I.; et al. (February 2013), "Oxygen abundances in nearby FGK stars and the galactic chemical evolution of the local disk and halo", The Astrophysical Journal, 764 (1): 78, arXiv:1301.1582, Bibcode:2013ApJ...764...78R, doi:10.1088/0004-637X/764/1/78.
  7. 1 2 Simpson, E. K.; et al. (November 2010), "Rotation periods of exoplanet host stars", Monthly Notices of the Royal Astronomical Society, 408 (3): 1666–1679, arXiv:1006.4121, Bibcode:2010MNRAS.408.1666S, doi:10.1111/j.1365-2966.2010.17230.x.
  8. ↑ Benjamin Apthorp Gould, reprinted; updated by Frederick Pilcher. "Uranometria Argentina". Archived from the original on 2012-02-27. Retrieved 2011-02-04.
  9. ↑ "HD 69830". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2015-04-25.
  10. ↑ Beichman, C. A.; et al. (2005). "An Excess Due to Small Grains around the Nearby K0 V Star HD 69830: Asteroid or Cometary Debris?". The Astrophysical Journal. 626 (2): 1061–1069. arXiv:astro-ph/0504491. Bibcode:2005ApJ...626.1061B. doi:10.1086/430059.
  11. 1 2 Lovis, Christophe; et al. (2006). "An extrasolar planetary system with three Neptune-mass planets" (PDF). Nature. 441 (7091): 305–309. arXiv:astro-ph/0703024. Bibcode:2006Natur.441..305L. doi:10.1038/nature04828. PMID 16710412.
  12. 1 2 Lisse, C. M.; et al. (2007). "On the Nature of the Dust in the Debris Disk Around HD 69830". The Astrophysical Journal. 658 (1): 584–592. arXiv:astro-ph/0611452. Bibcode:2007ApJ...658..584L. doi:10.1086/511001.
  13. ↑ "hd_69830_b". Extrasolar Planet Encyclopaedia. Retrieved November 12, 2012.
  14. ↑ Roberto Sanchis-Ojeda; Josh N. Winn; Daniel C. Fabrycky (2012). "Starspots and spin-orbit alignment for Kepler cool host stars". Astronomische Nachrichten. 334: 180. arXiv:1211.2002. Bibcode:2013AN....334..180S. doi:10.1002/asna.201211765.
  • Clavin, Whitney (2005-04-20). "NASA's Spitzer Telescope Sees Signs of Alien Asteroid Belt". NASA. Spitzer Space Telescope. Archived from the original on 2008-05-11. Retrieved 2008-06-13.
  • "HD 69830 / HR 3259". SolStation. Retrieved 2008-06-13.
  • "Notes for star HD 69830". The Extrasolar Planets Encyclopaedia. Retrieved 2008-06-13.
  • Than, Ker (2006-05-17). "Planets Found in Potentially Habitable Setup". SPACE.com. Retrieved 2008-06-13.
  • "Trio Of Neptunes And Their Belt". SpaceDaily. 2006-05-18. Retrieved 2008-06-13.
  • Extrasolar Planet Interactions by Rory Barnes & Richard Greenberg, Lunar and Planetary Lab, University of Arizona

Coordinates: 08h 18m 23.9s, −12° 37′ 55.0″

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