Astronomy:KELT-21b
| Discovery | |
|---|---|
| Discovered by | Marshall Johnson et al.[1] |
| Discovery site | KELT |
| Discovery date | 2018 |
| Transit method | |
| Orbital characteristics | |
| 0.05224 AU (7,815,000 km) | |
| Orbital period | 3.6127647[1] d |
| Inclination | 86.46[1] |
| Star | KELT-21 A (HD 332124) |
| Physical characteristics | |
| Mean radius | 1.586[1] |♃|J}}}}}} |
| Mass | <3.91[1] |♃|J}}}}}} |
| Mean density | <1.24 g cm−3 |
| Physics | 2051[1] |
KELT-21b is an extrasolar planet discovered in 2017. It is a hot Jupiter with radius of about 1.586 MJ.[1]
Host star
KELT-21b orbits KELT-21 A (HD 332124). It orbits the primary star in a triple star system, with the other two stars located 1.2 arcseconds away. These two stars, designated KELT-21 B and C, have masses of 0.13 M☉ and 0.11 M☉, respectively.[1] The primary star is heavy at 1.458±0.029M☉, extremely hot at 8210±771 K and rapidly rotating (equatorial velocity equal to 141 km/s).[2] The planetary orbit is well aligned with the equatorial plane of the host star, with misalignment equal to −5.6+1.7−1.9°[3]
Transmission planetary spectroscopy was performed in 2021, based on a single transit observation in 2019. High planetary gravity and relatively low planetary temperature made detection of an atmosphere impossible that time.[4]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Johnson, Marshall C; Rodriguez, Joseph E; Zhou, George; Gonzales, Erica J; Cargile, Phillip A; Crepp, Justin R; Penev, Kaloyan; Stassun, Keivan G et al. (2018). "KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating Metal-poor Late-A Primary of a Likely Hierarchical Triple System". The Astronomical Journal 155 (2): 100. doi:10.3847/1538-3881/aaa5af. Bibcode: 2018AJ....155..100J.
- ↑ Garai, Z.; Pribulla, T.; Kovács, J.; Szabó, Gy M.; Claret, A.; Komžík, R.; Kundra, E. (2022), "Rapidly rotating stars and their transiting planets: KELT-17b, KELT-19Ab, and KELT-21b in the CHEOPS and TESS era", Monthly Notices of the Royal Astronomical Society 513 (2): 2822–2840, doi:10.1093/mnras/stac1095
- ↑ Rice, Malena; Wang, Songhu; Wang, Xian-Yu; Stefánsson, Guđmundur; Isaacson, Howard; Howard, Andrew W.; Logsdon, Sarah E.; Schweiker, Heidi et al. (2022), "A Tendency Toward Alignment in Single-star Warm-Jupiter Systems", The Astronomical Journal 164 (3): 104, doi:10.3847/1538-3881/ac8153, Bibcode: 2022AJ....164..104R
- ↑ Stangret, M.; Casasayas-Barris, N.; Pallé, E.; Orell-Miquel, J.; Morello, G.; Luque, R.; Nowak, G.; Yan, F. (2022), "High-resolution transmission spectroscopy study of ultra-hot Jupiters HAT-P-57b, KELT-17b, KELT-21b, KELT-7b, MASCARA-1b, and WASP-189b", Astronomy & Astrophysics 662: A101, doi:10.1051/0004-6361/202141799, Bibcode: 2022A&A...662A.101S
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