TOI-178: Difference between revisions
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Transit-timing variation observations. |
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The planets are named from TOI-178b through to TOI-178g, according to the International Astronomical Union (IAU) defined [[exoplanet naming convention]]. The periods of the planets, in days, revolving around the star are b = 1.91, c = 3.24, d = 6.56, e = 9.96, f = 15.23, and g = 20.71. Planets c through g are said to be related via an 12:9:6:4:2 chain of resonance, since, for example, planet c goes around about 12 times for every 2 revolutions of planet g. |
The planets are named from TOI-178b through to TOI-178g, according to the International Astronomical Union (IAU) defined [[exoplanet naming convention]]. The periods of the planets, in days, revolving around the star are b = 1.91, c = 3.24, d = 6.56, e = 9.96, f = 15.23, and g = 20.71. Planets c through g are said to be related via an 12:9:6:4:2 chain of resonance, since, for example, planet c goes around about 12 times for every 2 revolutions of planet g. |
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The system is about 205 [[Light-year|light-years]] away, which is relatively close, implying that such systems may be relatively common.<ref name=":2" /><ref name=":0" /> The brightness of the star, TOI-178a, facilitates followup observations, which make it an ideal system in which to expand our understanding of planet formation and evolution.<ref name=":1" /> |
The system is about 205 [[Light-year|light-years]] away, which is relatively close, implying that such systems may be relatively common.<ref name=":2" /><ref name=":0" /> The brightness of the star, TOI-178a, facilitates followup observations, which make it an ideal system in which to expand our understanding of planet formation and evolution.<ref name=":1" /> Over the coming years, observations of [[Transit-timing variation|transit-timing variations]] in the transits of the various planets, which are expected to range from minutes to tens of minutes, should help pin down the planetary masses and uncover the eccentricities of the various orbits.<ref name=":1" /> |
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{{Orbitbox planet begin |
{{Orbitbox planet begin |
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Revision as of 18:21, 29 January 2021
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sculptor |
| Right ascension | 00h 29m 12.30s[1] |
| Declination | −30° 27′ 13.46″[1] |
| Apparent magnitude (V) | 11.95[1] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | K[1] |
| Astrometry | |
| Radial velocity (Rv) | 57.4±0.5[1] km/s |
| Proper motion (μ) | RA: 149.95±0.07[1] mas/yr Dec.: −87.25±0.04[1] mas/yr |
| Parallax (π) | 15.92 ± 0.05 mas[1] |
| Distance | 204.9 ± 0.6 ly (62.8 ± 0.2 pc) |
| Details | |
| Mass | 0.650+0.027 −0.029[1] M☉ |
| Radius | 0.651±0.011[1] R☉ |
| Luminosity (bolometric) | 0.132±0.010[1] L☉ |
| Surface gravity (log g) | 4.45±0.15[1] cgs |
| Temperature | 4316±70[1] K |
| Metallicity [Fe/H] | −0.23±0.05[1] dex |
| Rotational velocity (v sin i) | 1.5±0.3[1] km/s |
| Other designations | |
2MASS J00291228-3027133, Gaia DR2 2318295979126499200, TIC 251848941, TYC 6991-00475-1 | |
| Database references | |
| SIMBAD | data |
TOI-178 is a planetary system in the constellation Sculptor,[2] which appears to have at least five, and possibly six planets in a chain of Laplace resonances. That is one of the longest chains yet discovered in a system of planets. The system also has unusual variations in the densities among the planets.[3][4][1]
The planets are named from TOI-178b through to TOI-178g, according to the International Astronomical Union (IAU) defined exoplanet naming convention. The periods of the planets, in days, revolving around the star are b = 1.91, c = 3.24, d = 6.56, e = 9.96, f = 15.23, and g = 20.71. Planets c through g are said to be related via an 12:9:6:4:2 chain of resonance, since, for example, planet c goes around about 12 times for every 2 revolutions of planet g.
The system is about 205 light-years away, which is relatively close, implying that such systems may be relatively common.[4][3] The brightness of the star, TOI-178a, facilitates followup observations, which make it an ideal system in which to expand our understanding of planet formation and evolution.[1] Over the coming years, observations of transit-timing variations in the transits of the various planets, which are expected to range from minutes to tens of minutes, should help pin down the planetary masses and uncover the eccentricities of the various orbits.[1]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 1.50+0.39 −0.44 M🜨 |
0.02607±0.00078 | 1.914558±0.000018 | — | 88.8+0.8 −1.3° |
1.152+0.073 −0.070 R🜨 |
| c | 4.77+0.55 −0.68 M🜨 |
0.0370±0.0011 | 3.238450+0.000020 −0.000019 |
— | 88.4+1.1 −1.6° |
1.669+0.114 −0.099 R🜨 |
| d | 3.01+0.80 −1.03 M🜨 |
0.0592±0.0018 | 6.557700±0.000016 | — | 88.58+0.20 −0.18° |
2.572+0.075 −0.078 R🜨 |
| e | 3.86+1.25 −0.94 M🜨 |
0.0783+0.0023 −0.0024 |
9.961881±0.000042 | — | 88.71+0.16 −0.13° |
2.207+0.088 −0.090 R🜨 |
| f | 7.72+1.67 −1.52 M🜨 |
0.1039±0.0031 | 15.231915+0.000115 −0.000095 |
— | 88.723+0.071 −0.069° |
2.287+0.108 −0.110 R🜨 |
| g | 3.94+1.31 −1.62 M🜨 |
0.1275+0.0038 −0.0039 |
20.70950+0.00014 −0.00011 |
— | 88.823+0.045 −0.047° |
2.87+0.14 −0.13 R🜨 |
References
- ^ a b c d e f g h i j k l m n o p q r s Leleu, A.; Alibert, Y.; Hara, N. C.; Hooton, M. J.; Wilson, T. G.; Robutel, P.; Delisle, J. -B.; Laskar, J.; Hoyer, S.; Lovis, C.; Bryant, E. M.; Ducrot, E.; Cabrera, J.; Delrez, L.; Acton, J. S.; Adibekyan, V.; Allart, R.; Prieto, Allende; Alonso, R.; Alves, D.; et al. (2021-01-20). "Six transiting planets and a chain of Laplace resonances in TOI-178". Astronomy & Astrophysics. arXiv:2101.09260. doi:10.1051/0004-6361/202039767. ISSN 0004-6361. S2CID 231693292.
- ^ Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode:1987PASP...99..695R. doi:10.1086/132034.. Requête spécifique à TOI-178 sur VizieR.
- ^ a b Plait, Phil (2021-01-25). "A six-planet system dances in time to the tune of gravity". SYFY WIRE. Retrieved 2021-01-27.
- ^ a b "Nearby Orange Dwarf Hosts Unique System of Six Planets | Astronomy | Sci-News.com". Breaking Science News | Sci-News.com. Retrieved 2021-01-27.
