GJ 367b: A dense, ultrashort-period sub-Earth planet transiting a nearby red dwarf star
K. W. F. Lam, Szilárd Csizmadia, N. Astudillo-Defru, X. Bonfıls, D. Gandolfi, Sebastiano Padovan, M. Esposito, C. Hellier, Teruyuki Hirano, John H. Livingston, F. Murgas, A. M. S. Smith, Karen A. Collins, S. Mathur, R. A. García, Steve B. Howell, N. C. Santos, Fei Dai, G. Ricker, R. Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Simon Albrecht, J. M. Almenara, Étienne Artigau, Oscar Barragán, F. Bouchy, J. Cabrera, David Charbonneau, P. Chaturvedi, Alexander Chaushev, Jessie L. Christiansen, William D. Cochran, José R. De Meideiros, X. Delfosse, R. F. Díaz, René Doyon, Philipp Eigmüller, P. Figueira, T. Forveille, M. Fridlund, G. Gaisné, Elisa Goffo, Iskra Georgieva, S. Grziwa, E. W. Guenther, A. P. Hatzes, Marshall C. Johnson, P. Kábath, Emil Knudstrup, J. Korth, Pablo Lewin, Jack J. Lissauer, C. Lovis, R. Luque, C. Melo, E. Morgan, Robert Morris, M. Mayor, Norio Narita, H. L. M. Osborne, Ε. Πάλλη, F. Pepe, C. M. Persson, Samuel N. Quinn, H. Rauer, Seth Redfield, Joshua E. Schlieder, D. Ségransan, L. M. Serrano, Jeffrey C. Smith, J. Šubjak, Joseph D. Twicken, S. Udry, Vincent Van Eylen, Michael Vezie
Abstract
A nearby iron-rich sub-Earth planet The mass and radius of an exoplanet determine its mean density, which provides information about the possible interior structure. Lam et al . have identified a planet on a 7.7-hour orbit around a nearby red dwarf star. The authors determined the planet’s radius from the transit, then used radial velocity observations to measure the mass. They found a sub-Earth–sized planet with a density almost equivalent to pure iron. Its high surface temperature is close to the vaporization point of iron, suggesting that it is the iron core of a planet that has lost its outer mantle. —KTS