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| Discovery[1][2] | |
|---|---|
| Discovered by | Hellier et al. / Rodríguez Martínez et al. |
| Discovery date | November / December 2019 (announced) |
| Transit method | |
| Designations | |
| CD−42° 10057b, HD 134004 b, TIC 160708862 b, TOI-1337 b, TYC 7829-2324-1 b, 2MASS J15090488-4242178 b[3] | |
| Orbital characteristics[1] | |
| 0.0558±0.0010 AU | |
| Eccentricity | 0 |
| 3.3448285±0.0000012 d | |
| Inclination | 85.7°±0.6° |
| Semi-amplitude | 139±9 m/s |
| Star | WASP-178 |
| Physical characteristics[1] | |
| 1.81±0.09 RJ | |
| Mass | 1.66±0.12 MJ |
Mean density | 0.37±0.07 g/cm3 |
| Temperature | 2470±60 K (2,200 °C; 3,990 °F, equilibrium) |
WASP-178b, also known as KELT-26b and HD 134004 b, is an ultra-hot Jupiter exoplanet discovered in 2019 orbiting WASP-178, a hot A-type star located about 1,350 light-years (410 parsecs) away in the constellation of Lupus. At over 1.8 times the radius of Jupiter, it is among the largest exoplanets. In April 2022, a paper reported on the detection of silicon monoxide in its atmosphere, the first time the compound was discovered on an exoplanet.
Discovery and nomenclature
editThe planet was discovered by a team of astronomers led by Coel Hellier, who published their findings in November 2019, alongside the detection of three other planets, designated WASP-184b, WASP-185b, and WASP-192b. The four planets were all found through photometric analysis of astronomical transit data collected by WASP-South, hence the "WASP-" prefix. For WASP-178b, data was gathered over the course of eight years between May 2006 and August 2014, which was combined with follow-up observations by the CORALIE spectrograph and EulerCam, which are both part of the Swiss 1.2-metre Leonhard Euler Telescope.[1]
Another team, headed by Romy Rodríguez Martínez, independently announced discovering the planet in December 2019 as part of the Kilodegree Extremely Little Telescope (KELT) survey, labeling it KELT-26b. The host star was photometrically observed by the KELT-South telescope for two years between September 2013 and September 2015, identifying the object as a planetary candidate. Further observations confirmed the exoplanet, which were made by TESS, the Perth Exoplanet Survey Telescope (PEST), and the CHIRON spectrograph on the SMARTS 1.5 m telescope, located at the Cerro Tololo Inter-American Observatory (CTIO).[2] The planet was the 26th and final planet discovered by the KELT survey before it was decommissioned in 2020.[4]
Earlier designations of the host star include CD−42° 10057 in the Cordoba Durchmusterung catalogue and HD 134004 in the Henry Draper catalogue.[5]
Physical properties
editAtmosphere
editHost star
editThe host star, WASP-178, is a likely Am star[1] and possibly a Delta Scuti variable,[2] with a spectral type of A1IV-V,[1] meaning it is in between being a main sequence star and a subgiant. The star is comparable to Sirius A in mass and radius, but slightly cooler, older, and less luminous. It is about twice as massive as the Sun and has a radius of 1.67[1] or 1.80[2] R☉, with an effective temperature of roughly 9,000 K. A 2019 estimate of 9350±150 K makes WASP-178 the second-hottest host to a hot Jupiter ever discovered, behind KELT-9 (10,170 K) and ahead of MASCARA-2 (8,980 K),[1] though a lower estimate (8,640 K) provided by another paper[2] may put it below MASCARA-2. The star is around 20 times brighter than the Sun and is 430+310
−250 million years[2] old.
Comparison with Sirius A
edit| Identifier | Stellar Class |
Mass (M☉) |
Radius (R☉) |
Luminosity (L☉) |
Temperature (K) |
Metallicity (dex) |
Age (Myr) |
Notes |
|---|---|---|---|---|---|---|---|---|
| Sirius A | A0mA1 Va[6] | 2.063[7] | 1.713 | 24.7 | 9,845 | +0.50[8] | 242[7] | [9] |
| WASP-178 | A1IV-V | 2.07 | 1.67 | 21.4[10] | 9,350 | +0.21 | 430[2] | [1] |
See also
edit- Other ultra-hot Jupiters orbiting B- and A-type stars:
- KELT-9b: The hottest known exoplanet at >4,000 K.
- KELT-20b
- Kepler-13Ab
- MASCARA-1b
- WASP-33b
- WASP-189b
References
edit- ^ a b c d e f g h i Hellier, Coel; et al. (2019-11-21). "WASP-South hot Jupiters: WASP-178b, WASP-184b, WASP-185b, and WASP-192b". Monthly Notices of the Royal Astronomical Society. 490 (1): 1479–1487. doi:10.1093/mnras/stz2713. ISSN 0035-8711.
- ^ a b c d e f g Rodríguez Martínez, Romy; et al. (2020-09-01). "KELT-25 b and KELT-26 b: A Hot Jupiter and a Substellar Companion Transiting Young A Stars Observed by TESS*". The Astronomical Journal. 160 (3): 111. arXiv:1912.01017. Bibcode:2020AJ....160..111R. doi:10.3847/1538-3881/ab9f2d. ISSN 0004-6256.
- ^ "HD 134004". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2024-08-08.
- ^ "KELT Transit Search to conclude after 17 years of work". keltsurvey.org. Retrieved 14 April 2020.
- ^ Cannon, Annie Jump; Pickering, Edward C. (1921). The Henry Draper catalogue : 15h and 16h. Cambridge, Mass.: The Observatory. p. 21. OCLC 33326063.
- ^ Gray, R.O.; Corbally, C.J.; Garrison, R.F.; McFadden, M.T.; Robinson, P.E. (2003). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of stars earlier than M0 within 40 parsecs: The Northern Sample. I". Astronomical Journal. 126 (4): 2048–2059. arXiv:astro-ph/0308182. Bibcode:2003AJ....126.2048G. doi:10.1086/378365. S2CID 119417105.
- ^ a b Bond, Howard E.; Schaefer, Gail H.; Gilliland, Ronald L.; Holberg, Jay B.; Mason, Brian D.; Lindenblad, Irving W.; et al. (2017). "The Sirius system and its astrophysical puzzles: Hubble Space Telescope and ground-based astrometry". The Astrophysical Journal. 840 (2): 70. arXiv:1703.10625. Bibcode:2017ApJ...840...70B. doi:10.3847/1538-4357/aa6af8. S2CID 51839102.
- ^ Qiu, H. M.; Zhao, G.; Chen, Y. Q.; Li, Z. W. (2001). "The Abundance Patterns of Sirius and Vega". The Astrophysical Journal. 548 (2): 953–965. Bibcode:2001ApJ...548..953Q. doi:10.1086/319000. S2CID 122558713.
- ^ Davis, J.; et al. (October 2010). "The Angular Diameter and Fundamental Parameters of Sirius A". Publications of the Astronomical Society of Australia. 28: 56. arXiv:1010.3790. doi:10.1071/AS10010.
- ^ Stassun, Keivan G.; et al. (2019-10-01). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256.