K2-106, a system containing a metal-rich planet and a planet of lower density
(2017) In Astronomy and Astrophysics 608.- Abstract
Aims. Planets in the mass range from 2 to 15 M⊙ are very diverse. Some of them have low densities, while others are very dense. By measuring the masses and radii, the mean densities, structure, and composition of the planets are constrained. These parameters also give us important information about their formation and evolution, and about possible processes for atmospheric loss. Methods. We determined the masses, radii, and mean densities for the two transiting planets orbiting K2-106. The inner planet has an ultra-short period of 0.57 days. The period of the outer planet is 13.3 days. Results. Although the two planets have similar masses, their densities are very different. For K2-106b we derive Mb =... (More)
Aims. Planets in the mass range from 2 to 15 M⊙ are very diverse. Some of them have low densities, while others are very dense. By measuring the masses and radii, the mean densities, structure, and composition of the planets are constrained. These parameters also give us important information about their formation and evolution, and about possible processes for atmospheric loss. Methods. We determined the masses, radii, and mean densities for the two transiting planets orbiting K2-106. The inner planet has an ultra-short period of 0.57 days. The period of the outer planet is 13.3 days. Results. Although the two planets have similar masses, their densities are very different. For K2-106b we derive Mb = 8.36+0.96-0.94 M⊙, Rb = 1.52 ± 0.16 R⊙, and a high density of 13.1+5.4-3.6 g cm-3. For K2-106c, we find Mc = 5.8+3.3-3.0 M⊙, Rc = 2.50+0.27 0:26 R⊙ and a relatively low density of 2.0+1.6-1.1 g cm-3. Conclusions. Since the system contains two planets of almost the same mass, but different distances from the host star, it is an excellent laboratory to study atmospheric escape. In agreement with the theory of atmospheric-loss processes, it is likely that the outer planet has a hydrogen-dominated atmosphere. The mass and radius of the inner planet is in agreement with theoretical models predicting an iron core containing 80+20 30% of its mass. Such a high metal content is surprising, particularly given that the star has an ordinary (solar) metal abundance. We discuss various possible formation scenarios for this unusual planet.
(Less)
- author
- publishing date
- 2017-12-01
- type
- Contribution to journal
- publication status
- published
- keywords
- Planetary systems, Stars: Abundances, Stars: individual: TYC 608-458-1, Techniques: photometric, Techniques: Radial velocities
- in
- Astronomy and Astrophysics
- volume
- 608
- article number
- A93
- publisher
- EDP Sciences
- external identifiers
-
- scopus:85038207152
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361/201730885
- language
- English
- LU publication?
- no
- additional info
- Publisher Copyright: © ESO 2017.
- id
- 9a393902-4e5a-4e17-80a2-c260d8c50805
- date added to LUP
- 2023-02-02 12:49:27
- date last changed
- 2023-02-20 16:20:58
@article{9a393902-4e5a-4e17-80a2-c260d8c50805,
abstract = {{<p>Aims. Planets in the mass range from 2 to 15 M⊙ are very diverse. Some of them have low densities, while others are very dense. By measuring the masses and radii, the mean densities, structure, and composition of the planets are constrained. These parameters also give us important information about their formation and evolution, and about possible processes for atmospheric loss. Methods. We determined the masses, radii, and mean densities for the two transiting planets orbiting K2-106. The inner planet has an ultra-short period of 0.57 days. The period of the outer planet is 13.3 days. Results. Although the two planets have similar masses, their densities are very different. For K2-106b we derive Mb = 8.36<sup>+0.96</sup><sub>-0.94</sub> M⊙, Rb = 1.52 ± 0.16 R⊙, and a high density of 13.1<sup>+5.4</sup><sub>-3.6</sub> g cm<sup>-3</sup>. For K2-106c, we find Mc = 5.8<sup>+3.3</sup><sub>-3.0</sub> M⊙, Rc = 2.50+0.27 0:26 R⊙ and a relatively low density of 2.0<sup>+1.6</sup><sub>-1.1</sub> g cm<sup>-3</sup>. Conclusions. Since the system contains two planets of almost the same mass, but different distances from the host star, it is an excellent laboratory to study atmospheric escape. In agreement with the theory of atmospheric-loss processes, it is likely that the outer planet has a hydrogen-dominated atmosphere. The mass and radius of the inner planet is in agreement with theoretical models predicting an iron core containing 80+20 30% of its mass. Such a high metal content is surprising, particularly given that the star has an ordinary (solar) metal abundance. We discuss various possible formation scenarios for this unusual planet.</p>}},
author = {{Guenther, E. W. and Barragán, O. and Dai, F. and Gandolfi, D. and Hirano, T. and Fridlund, M. and Fossati, L. and Chau, A. and Helled, R. and Korth, J. and Prieto-Arranz, J. and Nespral, D. and Antoniciello, G. and Deeg, H. and Hjorth, M. and Grziwa, S. and Albrecht, S. and Hatzes, A. P. and Rauer, H. and Csizmadia, Sz and Smith, A. M.S. and Cabrera, J. and Narita, N. and Arriagada, P. and Burt, J. and Butler, R. P. and Cochran, W. D. and Crane, J. D. and Eigmüller, Ph and Erikson, A. and Johnson, J. A. and Kiilerich, A. and Kubyshkina, D. and Palle, E. and Persson, C. M. and Pätzold, M. and Sabotta, S. and Sato, B. and Shectman, A. and Teske, J. K. and Thompson, I. B. and Van Eylen, V. and Nowak, G. and Vanderburg, A. and Winn, J. N. and Wittenmyer, R. A.}},
issn = {{0004-6361}},
keywords = {{Planetary systems; Stars: Abundances; Stars: individual: TYC 608-458-1; Techniques: photometric; Techniques: Radial velocities}},
language = {{eng}},
month = {{12}},
publisher = {{EDP Sciences}},
series = {{Astronomy and Astrophysics}},
title = {{K2-106, a system containing a metal-rich planet and a planet of lower density}},
url = {{http://dx.doi.org/10.1051/0004-6361/201730885}},
doi = {{10.1051/0004-6361/201730885}},
volume = {{608}},
year = {{2017}},
}