Characterization of the K2-38 planetary system. Unraveling one of the densest planets known to date
B. Toledo-Padrón, C. Lovis, A. Suárez Mascareño, S. C. C. Barros, J. I. González Hernández, A. Sozzetti, F. Bouchy, M. R. Zapatero Osorio, R. Rebolo, S. Cristia… 展开作者
B. Toledo-Padrón, C. Lovis, A. Suárez Mascareño, S. C. C. Barros, J. I. González Hernández, A. Sozzetti, F. Bouchy, M. R. Zapatero Osorio, R. Rebolo, S. Cristiani, F. A. Pepe, N. C. Santos, S. G. Sousa, H. M. Tabernero, J. Lillo-Box, D. Bossini, V. Adibekyan, R. Allart, M. Damasso, V. D'Odorico, P. Figueira, B. Lavie, G. Lo Curto, A. Mehner, G. Micela, A. Modigliani, N. J. Nunes, E. Pallé, M. Abreu, M. Affolter, Y. Alibert, M. Aliverti, C. Allende Prieto, D. Alves, M. Amate, G. Avila, V. Baldini, T. Bandy, S. Benatti, W. Benz, A. Bianco, C. Broeg, A. Cabral, G. Calderone, R. Cirami, J. Coelho, P. Conconi, I. Coretti, C. Cumani, G. Cupani, S. Deiries, H. Dekker, B. Delabre, O. Demangeon, P. Di Marcantonio, D. Ehrenreich, A. Fragoso, L. Genolet, M. Genoni, R. Génova Santos, I. Hughes, O. Iwert, J. Knudstrup, M. Landoni, J. L. Lizon, C. Maire, A. Manescau, C. J. A. P. Martins, D. Mégevand, P. Molaro, M. J. P. F. G. Monteiro, M. A. Monteiro, M. Moschetti, E. Mueller, L. Oggioni, A. Oliveira, M. Oshagh, G. Pariani, L. Pasquini, E. Poretti, J. L. Rasilla, E. Redaelli, M. Riva, S. Santana Tschudi, P. Santin, P. Santos, A. Segovia, D. Sosnowska, P. Spanò, F. Tenegi, S. Udry, A. Zanutta, F. Zerbi
We characterized the transiting planetary system orbiting the G2V star K2-38 using the new-generation echelle spectrograph ESPRESSO. We carried out a photometric analysis of the available K2 photometric light curve of this star to measure the radius of its two known planets. Using 43 ESPRESSO high-precision radial velocity measurements taken over the course of 8 months along with the 14 previously published HIRES RV measurements, we modeled the orbits of the two planets through a MCMC analysis, significantly improving their mass measurements. Using ESPRESSO spectra, we derived the stellar parameters, $T_{\rm eff}$=5731$\pm$66, $\log g$=4.38$\pm$0.11~dex, and $[Fe/H]$=0.26$\pm$0.05~dex, and thus the mass and radius of K2-38, $M_{\star}$=1.03 $^{+0.04}_{-0.02}$~M$_{\oplus}$ and $R_{\star}$=1.06 $^{+0.09}_{-0.06}$~R$_{\oplus}$. We determine new values for the planetary properties of both planets. We characterize K2-38b as a super-Earth with $R_{\rm P}$=1.54$\pm$0.14~R$_{\rm \oplus}$ and $M_{\rm p}$=7.3$^{+1.1}_{-1.0}$~M$_{\oplus}$, and K2-38c as a sub-Neptune with $R_{\rm P}$=2.29$\pm$0.26~R$_{\rm \oplus}$ and $M_{\rm p}$=8.3$^{+1.3}_{-1.3}$~M$_{\oplus}$. We derived a mean density of $ρ_{\rm p}$=11.0$^{+4.1}_{-2.8}$~g cm$^{-3}$ for K2-38b and $ρ_{\rm p}$=3.8$^{+1.8}_{-1.1}$~g~cm$^{-3}$ for K2-38c, confirming K2-38b as one of the densest planets known to date. The best description for the composition of K2-38b comes from an iron-rich Mercury-like model, while K2-38c is better described by a rocky model with a H2 envelope. The maximum collision stripping boundary shows how giant impacts could be the cause for the high density of K2-38b. The irradiation received by each planet places them on opposite sides of the radius valley. We find evidence of a long-period signal in the radial velocity time-series whose origin could be linked to a 0.25-3~M$_{\rm J}$ planet or stellar activity.
Unraveling Year-Long Radial Velocity Variations in Red Clump Region -- I: Comprehensive analysis of a K0 Giant star, 2 Draconis
National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）；Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University（北京师范大学天文与地球深部研究中心）；Department of Astronomy, Beijing Normal University（北京师范大学天文系）；Department of Earth and Planetary Sciences, Institute of Science Tokyo（东京科学大学地球行星科学系）；Korea Astronomy and Space Science Institute（韩国天文与空间科学研究院）；Tsung-Dao Lee Institute, Shanghai Jiao Tong University（上海交通大学李政道研究所）；Astrobiology Center, National Institutes of Natural Sciences（国立自然科学研究所天体生物学中心）；National Astronomical Observatory of Japan, National Institutes of Natural Sciences（国立自然科学研究所日本国家天文台）；Subaru Telescope, National Astronomical Observatory of Japan, National Institutes of Natural Sciences（国立自然科学研究所日本国家天文台昴星团望远镜）；Okayama Branch, Subaru Telescope, National Astronomical Observatory of Japan, National Institutes of Natural Sciences（国立自然科学研究所日本国家天文台冈山分支昴星团望远镜）；Nishi-Harima Astronomical Observatory, Center for Astronomy, University of Hyogo（兵库县立大学天文中心西播磨天文台）；The Graduate University for Advanced Studies (SOKENDAI)（综合研究大学院大学）；Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology（麻省理工学院卡弗里天体物理与空间研究研究所）
Unraveling the Mystery of the Peculiar and Young Hot Jupiter CoRoT-2b II: Phase Resolved Emission Spectroscopy with VLT/CRIRES+ and Gemini-S/IGRINS
University of Warwick（华威大学）；Université de Montréal（蒙特利尔大学）；Institut de Recherche en Astrophysique et Planétologie (IRAP)（天体物理学与行星学研究所在）；Instituto de Astrofísica de Andalucía (IAA-CSIC)（安达卢西亚天体物理研究所）；Department of Astronomy, University of Michigan（密歇根大学天文学系）
