HD 3167 b
| Discovery[1] | |
|---|---|
| Discovered by | Andrew Vanderburg, et al. |
| Discovery site | Kepler (K2) |
| Discovery date | September 2016 |
| Transit | |
| Designations | |
| K2-96 b | |
| Orbital characteristics[2] | |
| 0.01814+0.00027 −0.00024 AU | |
| Eccentricity | 0 (fixed) |
| 0.95965451+0.00000022 −0.00000021 d | |
| Inclination | 87.8°+1.5° −1.6° |
| 90 (fixed) | |
| Semi-amplitude | 3.46±0.16 m/s |
| Star | HD 3167 |
| Physical characteristics[2] | |
| 1.601+0.048 −0.036 R🜨 | |
| Mass | 4.844+0.270 −0.254 M🜨 |
Mean density | 6.49+0.52 −0.60 g/cm3 |
| Temperature | 1781+18 −19 K (1,508 °C; 2,746 °F, equilibrium) |
HD 3167 b is a super-Earth exoplanet that orbits the K-type star HD 3167. With an orbital period of just 0.959 days, it belongs to the group of ultra-short period planets. The planet was shown to possess an atmosphere in a 2026 study, becoming the coolest lava planet with evidence for an atmosphere.[3] [2]
Characteristics
[edit]Radius, mass, composition and orbit
[edit]HD 3167 b was initially detected with the transit method, where the planet blocked a small percentage of its host star's light when passing between it and Earth. This allowed astronomers to accurately determine the planet's radius at 1.601 R🜨, with an uncertainty of 0.048 R🜨 (about 306 km). Radial velocity measurements helped constrain the planet's mass, which turned out to be around 5.02 M🜨. With both radius and mass known, the density of the planet can be calculated (about 6.74 g/cm3), which implies a mainly rocky composition.[4]
HD 3167 b orbits very close to its host star. One full revolution around HD 3167 takes only 0.959 days (~23 hours) to complete. It orbits in a nearly circular orbit at a distance of 0.01815 AU (2.72 million km), or about just four times the host star's radius.[4]
Atmosphere and relationship with the cosmic sandbar
[edit]A 2019 study put constraints on the presence of atmospheric sodium and calcium for HD 3167 b, which are potential signs of volcanic activity. At this time, the existence of an atmosphere on the planet remained unproven.[5]
JWST measurements of secondary eclipse reveals a substantially low white light eclipse depth, which is inconsistent with a "bare rock" planet with no atmosphere. This eclipse depth (along with the planet's slight under-dense density) are best explained by the existence of a significant atmosphere, which reflects incoming starlight and/or redistributes heat to the nightside of planet.[2]
In an effort to understand why some lava planets (such as HD 3167 b) are able to retain their atmospheres for long periods in spite of extreme stellar radiation, a new concept of "cosmic sandbar" was proposed. In this model, the atmospheres of HD 3167 b and similar planets are continuously regulated by outgassing process from the magma ocean, which acts as a reservoir for the volatile compounds.[6]
See also
[edit]References
[edit]- ↑ Vanderburg, Andrew; Bieryla, Allyson; et al. (September 2016). "Two Small Planets Transiting HD 3167". The Astrophysical Journal Letters. 829 (1): L9. arXiv:1607.05248. Bibcode:2016ApJ...829L...9V. doi:10.3847/2041-8205/829/1/L9. ISSN 2041-8205.
- 1 2 3 4 Park Coy, Brandon; Xue, Qiao; et al. (July 2026). "Evidence for an Atmosphere on the Ultra-short-period Super-Earth HD 3167 b". The Astrophysical Journal Letters. 1005 (2): L77. arXiv:2604.11911. Bibcode:2026ApJ..1005L..77C. doi:10.3847/2041-8213/ae7f23.
- ↑ "Atmosphere Detected On The Coldest Lava World To Date". astrobiology.com. September 2026.
- 1 2 Christiansen, Jessie L.; Vanderburg, Andrew; et al. (September 2017), "Three's Company: An Additional Non-transiting Super-Earth in the Bright HD 3167 System, and Masses for All Three Planets", The Astronomical Journal, 154 (3): 17, arXiv:1706.01892, Bibcode:2017AJ....154..122C, doi:10.3847/1538-3881/aa832d, S2CID 54196245, 122.
- ↑ Guenther, Eike W.; Kislyakova, Kristina G. (November 2019), Volcanic activity and the exosphere of HD3167 b, arXiv:1911.09916.
- ↑ Nguyen, Barron K. (August 2026). "An Evolving Cosmic Shoreline and Sandbar Bounding the Rocky Airless Valley". The Astrophysical Journal Letters. 1008. arXiv:2608.23912. doi:10.3847/2041-8213/ae9743.