Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Hydrus |
Right ascension | 01h 37m 53.57672s[1] |
Declination | −60° 30′ 41.4954″[1] |
Apparent magnitude (V) | 7.33[2] |
Characteristics | |
Evolutionary stage | Main sequence |
Spectral type | G1V[3] |
Astrometry | |
Radial velocity (Rv) | +35.2[3] km/s |
Proper motion (μ) | RA: -14.60[1] mas/yr Dec.: 6.51[1] mas/yr |
Parallax (π) | 25.63 ± 0.38 mas[1] |
Distance | 127 ± 2 ly (39.0 ± 0.6 pc) |
Details | |
Mass | 1.062 ± 0.017[4] M☉ |
Radius | 1.20 ± 0.318[4] R☉ |
Luminosity | 1.49 ± 0.02[5] L☉ |
Surface gravity (log g) | 4.39[6] cgs |
Temperature | 5,911[6] K |
Metallicity [Fe/H] | 0.08[6] dex |
Rotation | 24 ± 3 days[5] |
Rotational velocity (v sin i) | < 3[5] km/s |
Age | 7.3[7] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
HD 10180, also designated 2MASS J01375356-6030414,[8] is a Sun-like star in the southern constellation Hydrus that is notable for its large planetary system. Since its discovery, at least six planets, and possibly as many as nine, have been observed orbiting it, making it potentially the largest of all known planetary systems, including the Solar System.[9][5]
Characteristics
Based upon parallax measurements, it is located at a distance of about 127 light-years (39 parsecs) from Earth.[10] The apparent visual magnitude of this star is 7.33, which is too faint to be viewed with the naked eye although it can be readily observed with a small telescope.[11] At a declination of −60°, this star cannot be seen at latitudes north of the tropics.
HD 10180 is a G1V-type star, and thus generates energy at its core through the thermonuclear fusion of hydrogen. The mass of this star is estimated as 6% greater than the Sun's mass, it has a radius of 120% that of the Sun, and is radiating 149% of the Sun's luminosity. The effective temperature of the star's chromosphere is 5,911 K, giving it a yellow-hued glow like the Sun.[12] HD 10180 has a 20% higher abundance of elements other than hydrogen/helium compared to the Sun.[note 1] With an estimated age of 7.3 billion years, it is a stable star with no significant magnetic activity. The estimated period of rotation is about 24 days.[5]
A survey in 2015 ruled out the existence of any stellar companions at projected distances from 13 to 324 astronomical units.[13]
Planetary system
Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | >1.3 ± 0.8 M🜨 | 0.02222 ± 0.00011 | 1.17766 ± 0.00022 | 0.05+0.49 −0.05[9] |
— | — |
c | >13.0 ± 2.0 M🜨 | 0.06412±0.00101 | 5.75969±0.00028 | 0.073±0.031 | ≥0.2841° | — |
i (unconfirmed) | >1.9 ± 1.8 M🜨 | 0.0904 ± 0.047 | 9.655 ± 0.072 | 0.05 ± 0.23 | — | — |
d | >11.9 ± 2.15 M🜨 | 0.12859±0.00202 | 16.357±0.0038 | 0.131±0.052 | ≥0.2005° | — |
e | >25.0 ± 3.9 M🜨 | 0.2699±0.0043 | 49.748±0.025 | 0.051±0.033 | ≥0.2366° | — |
j (unconfirmed) | >5.1 ± 3.2 M🜨 | 0.330 ± 0.016 | 67.55 ± 1.28 | 0.07 ± 0.12 | — | — |
f | >19.4±1.2[17] M🜨 | 0.4929±0.0078 | 122.744±0.232 | 0.119±0.054 | ≥0.3028° | — |
g | >21.4 ± 3.4 M🜨 | 1.427±0.028 | 615[17] | 0.15±0.10[17] | ≥0.3663° | — |
h | > 46.3±3.4[17] M🜨 | 3.381±0.121 | 2500[17] | 0.095±0.086 | ≥0.5496° | — |
On August 24, 2010, a research team led by Christophe Lovis of the University of Geneva announced that the star has at least five planets, and possibly as many as seven.[5][18] The planets were detected using the HARPS spectrograph, in conjunction with the ESO's 3.6 m telescope at La Silla Observatory in Chile, using Doppler spectroscopy.
On April 5, 2012, astronomer Mikko Tuomi of the University of Hertfordshire submitted a paper to Astronomy and Astrophysics approved for publishing on the April 6, 2012 that proposed a nine planet model for the system. Re-analysing the data using Bayesian probability analysis, previously known planets' parameters were revised and further evidence was found for the innermost planet (b) as well as evidence of two additional planets (i and j).
The system is not known to be a transiting planetary system and as such planets are unlikely to be detected or verified by the transit method.
In 2017, an orbital simulation showed that the formation of dynamically stable families of comets in the HD 10180 system is unlikely. The identified reason for the instability of cometary orbits was the location of the most massive planet HD 10180 h in the outermost orbit.[19]
Orbital arrangement
![](https://web.archive.org/web/20220521013318im_/https://upload.wikimedia.org/wikipedia/commons/thumb/0/0f/HD10180Orbits.svg/220px-HD10180Orbits.svg.png)
The system contains six planets with minimum masses from 12 to 65 times Earth's (ranging in mass from roughly Uranus to Saturn) at orbital radii of 0.06, 0.13, 0.27, 0.49, 1.42 and 3.4 AU. In the Solar System this set of orbits would fit within the main asteroid belt.
There are no planets known to be in mean-motion resonances, although it has a number of near resonances[5] including 3c:2i:1d and 3e:2j:1f. The approximate ratios of periods of adjacent orbits are (proceeding outward): 1:5, 1:3, 1:3, 2:5, 1:5, 3:11.
Since the inclination of the planets' orbits is unknown, only minimum planetary masses can presently be obtained. Dynamical simulations suggest that the system cannot be stable if the true masses of the planets exceed the minimum masses by a factor of greater than three (corresponding to an inclination of less than 20°, where 90° is edge-on).[5]
Planets
HD 10180 b is a possible Earth-sized planet (minimum mass 1.4 times Earth's) located at 0.02 AU. Its orbital radius was originally estimated to have a near-circular orbit at a distance of 0.02225 ± 0.00035 AU (closer than Mercury, about one-seventh the distance and correspondingly hotter), taking 1.1 days to complete a full orbit.[20] Planet b was confirmed in 2012 with a slightly smaller orbital radius and a more eccentric orbit. The false detection probability was initially 1.4%;[5] its probability was improved by Mikko Tuomi in 2012, but it was not confirmed by Kane in 2014.[14]
HD 10180 c, with a minimum mass comparable to that of Uranus, is a hot Neptune. Dynamical simulations suggest that if the mass gradient was any more than a factor of two, the system would not be stable. Its orbital period and eccentricity were originally estimated at 5.75979 ± 0.00062 and 0.045 ± 0.026 respectively; however, these were revised in 2012 in favour of a more eccentric orbit. The false detection probability is less than 0.1%.[5]
HD 10180 i is a possible but unconfirmed hot super-Earth claimed by Mikko Tuomi in 2012.
HD 10180 d is a hot Neptune. Its mass was initially estimated at >11.75 ± 0.65 (smaller than Uranus) and on a slightly eccentric orbit; however, this was re-estimated with a larger mass and less eccentric orbit in 2012.
HD 10180 e was initially thought to be a hot Neptune with about twice the mass of Neptune. Its estimated orbital distance and eccentricity were downscaled in 2012. The false detection probability is less than 0.1%.[5] However, a later analysis indicated the planet's true mass, which depends greatly on its orbital inclination and only the lower-limit of that has been calculated to any degree of certainty, could in theory be much higher at 20 times Jupiter’s mass and so there is a small chance it could be a brown dwarf instead of a planet.[16]
HD 10180 j is a possible but unconfirmed hot super-Earth or gas dwarf claimed by Mikko Tuomi in 2012.
HD 10180 f is a hot Neptune and of similar in mass to HD 10180 e. At orbital distance of 0.49AU and eccentricity of 0.13, its tight and wild orbit is analogous to that of Mercury with a similar black-body-temperature range though with its immense mass, any greenhouse effect caused by an atmosphere would give it searing Venus-like or greater temperatures. Estimated orbital distance and eccentricity were downscaled slightly in 2012. The false detection probability is less than 0.1%.[5] A later analysis indicated the planet's true mass, depending on its orbital inclination of which only the lower-limit has been calculated with any certainty, could in theory be much higher at 14 times Jupiter’s mass and so there is a small chance it could actually be a brown dwarf.[16]
HD 10180 g is a giant planet with a mass larger than Neptune's. It has a significantly eccentric orbit[14] at 1.4 AU and either crosses the system's predicted habitable zone or lies within it[21] though it does not fit the current models for planetary habitability due to its large mass (24 times Earth). If it is a gas giant, it is likely of Sudarsky Class II. There is a possibility that a natural satellite with sufficient atmospheric pressure could have liquid water on its surface. Its estimated orbital distance and eccentricity were downscaled in 2012 but remains in the habitable zone. The false detection probability is less than 0.1%.[5]
HD 10180 h is the largest and outermost known planet in the system. Originally, it was thought to be a Saturn-sized giant planet with a minimum mass 65 times that of Earth. Orbiting at 3.4 AU, a distance comparable to the distance of the outer part of the asteroid belt from the Sun and as such it is likely a Sudarsky Class I planet. The spurious detection probability is 0.6%. A later analysis indicated the planet's true mass, depending on its orbital inclination of which only the lower-limit has been estimated to any degree of certainty, could in theory be much higher at 22 times Jupiter’s mass and so there is a possibility that it is massive enough to be a brown dwarf.[16]
See also
- Kepler-90 A star with eight known planets (the first known to have an equal number of planets as the solar system).
- TRAPPIST-1 A star with seven known planets.
Notes
- ^ For [Fe/H] equal to 0.08, the proportion is given by:
- 100.08 = 1.20
- ^ The parameters are taken from the Newtonian fit taking into account tidal dissipation given in table 6 of Lovis et al. (2010). A purely Keplerian solution with slightly different parameters is given in table 3 of the same paper.
References
- ^ a b c d e van Leeuwen, F. (November 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. S2CID 18759600.
- ^ a b "HD 10180 -- Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2010-08-24.
- ^ a b Nordström, B.; et al. (May 2004). "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs". Astronomy and Astrophysics. 418 (3): 989–1019. arXiv:astro-ph/0405198. Bibcode:2004A&A...418..989N. doi:10.1051/0004-6361:20035959. S2CID 11027621.
- ^ a b Takeda, Genya; Ford, Eric B.; Sills, Alison; Rasio, Frederic A.; Fischer, Debra A.; Valenti, Jeff A. (2007). "Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog". The Astrophysical Journal Supplement Series. 168 (2): 297. arXiv:astro-ph/0607235. Bibcode:2007ApJS..168..297T. doi:10.1086/509763. S2CID 18775378.
- ^ a b c d e f g h i j k l m Lovis, C; et al. (August 8, 2010). "The HARPS search for southern extra-solar planets XXVII. Up to seven planets orbiting HD 10180: probing the architecture of low-mass planetary systems". Astronomy & Astrophysics. 528: A112. arXiv:1011.4994. Bibcode:2011A&A...528A.112L. doi:10.1051/0004-6361/201015577. S2CID 73558341.
- ^ a b c Sousa, S. G.; et al. (August 2007), "Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes", Astronomy and Astrophysics, 487 (1): 373–381, arXiv:0805.4826, Bibcode:2008A&A...487..373S, doi:10.1051/0004-6361:200809698, S2CID 18173201
- ^ Holmberg, J.; Nordström, B.; Andersen, J. (July 2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics Supplement Series. 501 (3): 941–947. arXiv:0811.3982. Bibcode:2009A&A...501..941H. doi:10.1051/0004-6361/200811191. S2CID 118577511. Note: see VizieR catalogue V/130.
- ^ "2MASS J01375356-6030414". SIMBAD. Centre de données astronomiques de Strasbourg.
- ^ a b Tuomi, Mikko (6 April 2012). "Evidence for 9 planets in the 10180 system". Astronomy & Astrophysics. 543: A52. arXiv:1204.1254v1. Bibcode:2012A&A...543A..52T. doi:10.1051/0004-6361/201118518. S2CID 15876919.
- ^ Gill, Victoria (August 24, 2010). "Rich exoplanet system discovered". BBC News. BBC. Retrieved August 24, 2010.
- ^ Sherrod, P. Clay; Koed, Thomas L. (2003). A Complete Manual of Amateur Astronomy: Tools and Techniques for Astronomical Observations. Astronomy Series. Courier Dover Publications. p. 9. ISBN 978-0-486-42820-8.
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on March 10, 2012, retrieved 2012-01-16
- ^ Mugrauer, M.; Ginski, C. (12 May 2015). "High-contrast imaging search for stellar and substellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 450 (3): 3127–3136. doi:10.1093/mnras/stv771. Retrieved 19 June 2020.
- ^ a b c Kane, Stephen R.; Gelino, Dawn M. (2014), "On the Inclination and Habitability of the Hd 10180 System", The Astrophysical Journal, 792 (2): 111, arXiv:1408.4150, Bibcode:2014ApJ...792..111K, doi:10.1088/0004-637X/792/2/111, S2CID 42857278
- ^ Planet HD 10180 b on exoplanet.eu
- ^ a b c d Kiefer, F.; et al. (2020). "Determining the true mass of radial-velocity exoplanets with Gaia". Astronomy & Astrophysics. 645: A7. arXiv:2009.14164. doi:10.1051/0004-6361/202039168.VizieR-table 9
- ^ a b c d e YARARA: Significant improvement of RV precision through post-processing of spectral time-series, 2021, arXiv:2106.07301
- ^ "Richest Planetary System Discovered: Up to seven planets orbiting a Sun-like star" (Press release). European Southern Observatory. August 24, 2010. Retrieved 2010-08-24.
- ^ Loibnegger, Birgit; Dvorak, Rudolf; Cuntz, Manfred (2017), "Case Studies of Exocomets in the System of HD 10180", The Astronomical Journal, 153 (5): 203, arXiv:1712.02386, Bibcode:2017AJ....153..203L, doi:10.3847/1538-3881/aa67ef, S2CID 119295263
- ^ Chang, Kenneth. "Kepler Telescope Detects Possible Earth-Size Planet", The New York Times, August 26, 2010. Accessed August 26, 2010.
- ^ "Solar System 2.0 (beta) - Planetary Habitability Laboratory @ UPR Arecibo".
External links
- Nemiroff, R.; Bonnell, J., eds. (2010-08-25). "HD 10180: Richest Yet Planetary System Discovered". Astronomy Picture of the Day. NASA. Retrieved 2010-08-25.
- Marchis, Franck (2010-08-24). "Discovery of 7 exoplanets around a Sun-like star". NASA's blog at Cosmic Diary. International Year of Astronomy. Archived from the original on 2012-05-08. Retrieved 2010-08-24.