HAT-P-18 - Planet - astro.wikisort.org

astro.wikisort.org - Planet

HAT-P-18 is a K-type main-sequence star about 530 light-years away. The star is very old and has a concentration of heavy elements similar to solar abundance.[4] A survey in 2015 detected very strong starspot activity on HAT-P-18.[5]

HAT-P-18
Observation data Epoch J2000 Equinox J2000
Constellation	Hercules
Right ascension	17^h 05^m 23.1476^s[1]
Declination	+33° 00′ 44.9391″[1]
Apparent magnitude (V)	12.759[2]
Characteristics
Spectral type	K2V
Astrometry

Radial velocity (R_v)	-11.83 km/s
Proper motion (μ)	RA: -14.073 mas/yr Dec.: -36.689 mas/yr
Parallax (π)	6.1669 ± 0.0231 mas[1]
Distance	529 ± 2 ly (162.2 ± 0.6 pc)

Details[3]

Mass	0.750^+0.015 _−0.014 `M`_☉
Radius	0.7202^+0.0095 _−0.01 `R`_☉
Luminosity	0.27±0.04[4] `L`_☉
Surface gravity (log g)	4.599±0.013 cgs
Temperature	4835⁺³⁹ ₋₃₅ K
Metallicity	0.044^+0.060 _−0.051
Rotation	14.66±0.03 d[4]
Rotational velocity (v sin i)	0.5±0.5[4] km/s
Age	12.4^+4.4 _−6.4[4] Gyr

Other designations
Gaia DR2 1334573817793362560, GSC 02594-00646, 2MASS J17052315+3300450[1]
Database references
SIMBAD	data

Planetary system

In 2010 a transiting hot Saturn-sized planet was detected.[2] Its equilibrium temperature is 841 K.[6]

In 2014, observations utilizing the Rossiter–McLaughlin effect detected an exoplanet, HAT-P-18b, on a retrograde orbit, with an angle between orbital plane of the planet and the parent star equatorial plane equal to 132±15°.[7]

Transit-timing variation measurements in 2015 did not detect additional planets in the system.[8]

In 2016, the transmission optical spectra of the planet indicated that the atmosphere is lacking detectable clouds or hazes, and is blue in color due to Rayleigh scattering of light.[9] The atmosphere seems to gradually evaporate, but at a slow rate - less than 2% of planetary mass is lost per one billion years.[10]

The dayside temperature of HAT-P-18b was measured in 2019 to be 1004⁺⁷⁸
₋₉₄ K.[11]

The HAT-P-18 planetary system[2]
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	0.183^+0.034 _−0.032 M_J	0.04649±	5.508029±0.0000042	0.106^+0.15 _−0.084	88.79±0.21°	0.947±0.044 R_J

References

HAT-P-18 -- Star
Hartman, J. D.; Bakos, G. Á.; Sato, B.; Torres, G.; Noyes, R. W.; Latham, D. W.; Kovács, G.; Fischer, D. A.; Howard, A. W.; Johnson, J. A.; Marcy, G. W.; Buchhave, L. A.; Füresz, G.; Perumpilly, G.; Béky, B.; Stefanik, R. P.; Sasselov, D. D.; Esquerdo, G. A.; Everett, M.; Csubry, Z.; Lázár, J.; Papp, I.; Sári, P. (2010), "HAT-P-18b and HAT-P-19b: Two Low-Density Saturn-Mass Planets Transiting Metal-Rich K Stars", The Astrophysical Journal, 726: 52, arXiv:1007.4850, doi:10.1088/0004-637X/726/1/52, S2CID 10896305
Wang, Xian-Yu; et al. (1 July 2021). "Transiting Exoplanet Monitoring Project (TEMP). VI. The Homogeneous Refinement of System Parameters for 39 Transiting Hot Jupiters with 127 New Light Curves". The Astrophysical Journal Supplement Series. 255 (1). 15. arXiv:2105.14851. Bibcode:2021ApJS..255...15W. doi:10.3847/1538-4365/ac0835.
Everett, Mark E.; Howell, Steve B.; Silva, David R.; Szkody, Paula (2013), "Spectroscopy of Faint Kepler Mission Exoplanet Candidate Host Stars", The Astrophysical Journal, 771 (2): 107, arXiv:1305.0578, doi:10.1088/0004-637X/771/2/107, S2CID 119270620
Piskorz, Danielle; Knutson, Heather A.; Ngo, Henry; Muirhead, Philip S.; Batygin, Konstantin; Crepp, Justin R.; Hinkley, Sasha; Morton, Timothy D. (2015), "Friends of Hot Jupiters. III. An Infrared Spectroscopic Search for Low-Mass Stellar Companions", The Astrophysical Journal, 814 (2): 148, arXiv:1510.08062, doi:10.1088/0004-637X/814/2/148, S2CID 11525988
Planet HAT-P-18 b at exoplanets.eu
Esposito, M.; Covino, E.; Mancini, L.; Harutyunyan, A.; Southworth, J.; Biazzo, K.; Gandolfi, D.; Lanza, A. F.; Barbieri, M.; Bonomo, A. S.; Borsa, F.; Claudi, R.; Cosentino, R.; Desidera, S.; Gratton, R.; Pagano, I.; Sozzetti, A.; Boccato, C.; Maggio, A.; Micela, G.; Molinari, E.; Nascimbeni, V.; Piotto, G.; Poretti, E.; Smareglia, R. (2014), The GAPS Programme with HARPS-N at TNG. III: The retrograde orbit of HAT-P-18b, arXiv:1403.6728, doi:10.1051/0004-6361/201423735, S2CID 59939759
Seeliger, M.; Kitze, M.; Errmann, R.; Richter, S.; Ohlert, J. M.; Chen, W. P.; Guo, J. K.; Göğüş, E.; Güver, T.; Aydın, B.; Mottola, S.; Hellmich, S.; Fernandez, M.; Aceituno, F. J.; Dimitrov, D.; Kjurkchieva, D.; Jensen, E.; Cohen, D.; Kundra, E.; Pribulla, T.; Vaňko, M.; Budaj, J.; Mallonn, M.; Wu, Z.-Y.; Zhou, X.; Raetz, St.; Adam, C.; Schmidt, T. O. B.; Ide, A.; et al. (2015), "Ground-based transit observations of the HAT-P-18, HAT-P-19, HAT-P-27/WASP40 and WASP-21 systems", Monthly Notices of the Royal Astronomical Society, 451 (4): 4060–4072, arXiv:1508.06215, doi:10.1093/mnras/stv1187, S2CID 56034663
Kirk, J.; Wheatley, P. J.; Louden, T.; Doyle, A. P.; Skillen, I.; McCormac, J.; Irwin, P. G. J.; Karjalainen, R. (2016), "Rayleigh scattering in the transmission spectrum of HAT-P-18b", Monthly Notices of the Royal Astronomical Society, 468 (4): 3907–3916, arXiv:1611.06916, doi:10.1093/mnras/stx752, S2CID 1058289
Paragas, Kimberly; Vissapragada, Shreyas; Knutson, Heather A.; Oklopčić, Antonija; Chachan, Yayaati; Greklek-Mckeon, Michael; Dai, Fei; Tinyanont, Samaporn; Vasisht, Gautam (2021), "Metastable Helium Reveals an Extended Atmosphere for the Gas Giant HAT-P-18b", The Astrophysical Journal Letters, 909: L10, arXiv:2102.08392, doi:10.3847/2041-8213/abe706, S2CID 231942657
Wallack, Nicole L.; Knutson, Heather A.; Morley, Caroline V.; Moses, Julianne I.; Thomas, Nancy H.; Thorngren, Daniel P.; Deming, Drake; Désert, Jean-Michel; Fortney, Jonathan J.; Kammer, Joshua A. (2019), "Investigating Trends in Atmospheric Compositions of Cool Gas Giant Planets UsingSpitzer Secondary Eclipses", The Astronomical Journal, 158 (6): 217, arXiv:1908.00014, doi:10.3847/1538-3881/ab2a05, S2CID 199064423

Constellation of Hercules

Stars

Bayer	α (Rasalgethi) β (Kornephoros) γ δ (Sarin) ε ζ η θ ι κ (Marsic) λ (Maasym) μ ν ξ ο π ρ σ τ υ φ χ ω (Cujam)
Flamsteed	14 29 (h) 30 (g) 42 45 (l) 52 60 68 (u) 69 (e) 72 (w) 89 93 98 99 (b) 102 104 (A) 106 109 110 111 32 Oph
Variable	AC AM DI DQ V446 V533 V535 V600 V624 V636 V640 V642 V644 V656 V728 V771 V772 V773 V775 V777 V838
HR	6669 6697 6806
HD	146389 147506 149026 (Ogma) 154345 155358 156668 164595 164922
Other	BD +17° 3248 Furuhjelm 46 GD 362 Gliese 623 Gliese 638 Gliese 649 Gliese 686 GJ 3991 HAT-P-18 Hercules X-1 GSC 02620-00648 GSC 03089-00929 Ross 640 WISE 1738+2732 WISE 1741+2553

Exoplanets	14 Herculis b c Smertrios HD 164922 b c d

Star clusters	Messier 13 Messier 92 NGC 6229 Palomar 14

Nebulae	Abell 39 NGC 6210

Galaxies

NGC	6028 6039 6040 6041 6042 6043 6044 6045 6046 6047 6052 6053 6054 6055 6056 6057 6061 6158 6166 6181 6207 6212 6239 6263 6452 6560
Other	A2261-BCG Arp 272 (NGC 6050 and IC 1179) AT2018cow Hercules Dwarf Hercules A Markarian 501 MCG+07-33-027 QSR J1819+3845

Galaxy clusters	Abell 2152 Abell 2199 Hercules Cluster Hercules Superclusters Zwicky's Triplet

Astronomical events	LBG-2377

На других языках

- [en] HAT-P-18

[ru] HAT-P-18

HAT-P-18 — звезда, которая находится в созвездии Геркулес на расстоянии около 541 светового года от нас. Вокруг звезды обращается, как минимум, одна планета.

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