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HD 69830

Coordinates: Sky map 08h 18m 23.9s, −12° 37′ 55.0″
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HD 69830
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Puppis
Right ascension 08h 18m 23.94697s[1]
Declination −12° 37′ 55.8172″[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)30.09±0.12[1] km/s
Proper motion (μ) RA: 278.790 mas/yr[1]
Dec.: −987.829 mas/yr[1]
Parallax (π)79.4953 ± 0.0400 mas[1]
Distance41.03 ± 0.02 ly
(12.579 ± 0.006 pc)
Absolute magnitude (MV)5.47 ± 0.01[4]
Details
Mass0.89 ± 0.03[5] 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, 2MASS J08182389-1237541, Gaia DR2 5726982995343100928[9]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata

HD 69830 (285 G. Puppis) is a yellow dwarf star located 41.0 light-years (12.6 parsecs) 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

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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 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

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The HD 69830 planetary system[11][12][5]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b ≥10.1+0.38
−0.37 M🜨 		0.0764±0.0017 8.66897±0.00028 0.128±0.028 — —
c ≥12.09+0.55
−0.54 M🜨 		0.181±0.004 31.6158±0.0051 0.03±0.027 — —
d ≥12.26+0.89
−0.88 M🜨 		0.622±0.014 201.4±0.4 0.08±0.071 — —
Asteroid belt 0.93–1.16 AU — —

Planets

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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.[11] 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.[11]

The planetary parameters were updated in 2023.[5]

Debris disk

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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 in 2007 revealed that it is composed of highly processed material, likely derived from a disrupted rocky 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]

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  • A comparison between the night sky of Earth and a planet of HD 69830.
    A comparison between the night sky of Earth and a planet of HD 69830.
  • The orbits of the planets of HD 69830 and the debris disk.
    The orbits of the planets of HD 69830 and the debris disk.

In fiction

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  • In the first-person shooter videogame franchise Halo, the homeworld of the Kig-Yar species is a moon orbiting within the HD 69830 system, with the system being known as "Y'Deio" the third planet in the system called "Chu'ot" and their homeworld being called Eayn.

See also

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References

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  1. ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c 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. ^ a b c d e f g 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, S2CID 16097733, 115.
  4. ^ 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. S2CID 118577511.Vizier catalog entry
  5. ^ a b c Laliotis, Katherine; Burt, Jennifer A.; et al. (February 2023). "Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions". The Astronomical Journal. 165 (4): 176. arXiv:2302.10310. Bibcode:2023AJ....165..176L. doi:10.3847/1538-3881/acc067.
  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, S2CID 118751608.
  7. ^ a b 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, S2CID 6708869.
  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.{{cite web}}: CS1 maint: postscript (link)
  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. S2CID 14003614.
  11. ^ a b c d 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. S2CID 4343578. Archived from the original (PDF) on 2016-03-03. Retrieved 2013-11-22.
  12. ^ a b 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. S2CID 53460002.
  13. ^ "hd_69830_b". Extrasolar Planets 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 (1–2): 180–183. arXiv:1211.2002. Bibcode:2013AN....334..180S. doi:10.1002/asna.201211765. S2CID 38743202.
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