Separated Twins or Just Siblings? A Multiplanet System around an M Dwarf Including a Cool Sub-Neptune
Article
Article Title | Separated Twins or Just Siblings? A Multiplanet System around an M Dwarf Including a Cool Sub-Neptune |
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ERA Journal ID | 45091 |
Article Category | Article |
Authors | Harris, Mallory, Dragomir, Diana, Mireles, Ismael, Collins, Karen A., Ulmer-Moll, Solène, Howell, Steve B., Stassun, Keivan G., Zhou, George, Ziegler, Carl Z, Bouchy, François, Briceno, César, Charbonneau, David, Collins, Kevin I., Furesz, Gábor, Guerrero, Natalia M., Jenkins, Jon M., Jensen, Eric L. N., Kristiansen, Martti H. K., Law, Nicholas, Lendl, Monika, Mann, Andrew W., Osborn, Hugh P., Quinn, Samuel N., Ricker, George R., Schwarz, Richard P., Seager, Sara, Ting, Eric B., Vanderspek, Roland, Watanabe, David and Winn, Joshua N. |
Journal Title | The Astrophysical Journal Letters |
Journal Citation | 959 (1) |
Article Number | L1 |
Number of Pages | 14 |
Year | 2023 |
Publisher | IOP Publishing |
Place of Publication | United Kingdom |
ISSN | 2041-8205 |
2041-8213 | |
Digital Object Identifier (DOI) | https://doi.org/10.3847/2041-8213/ad037d |
Web Address (URL) | https://iopscience.iop.org/article/10.3847/2041-8213/ad037d |
Abstract | We report the discovery of two TESS sub-Neptunes orbiting the early M dwarf TOI-904 (TIC 261257684). Both exoplanets, TOI-904 b and c, were initially observed in TESS Sector 12 with twin sizes of - + 2.426 0.157 0.163 and - + 2.167 0.118 0.130 R⊕, respectively. Through observations in five additional sectors in the TESS primary mission and the first and second extended missions, the orbital periods of the planets were measured to be 10.887 ± 0.001 and 83.999 ± 0.001 days, respectively. Reconnaissance radial velocity measurements (taken with EULER/CORALIE and SMARTS/CHIRON) and high-resolution speckle imaging with adaptive optics (obtained from SOAR/ HRCAM and Gemini South/ZORRO) show no evidence of an eclipsing binary or a nearby companion, which, together with the low false-positive probabilities calculated with the statistical validation software TRICERATOPS, establishes the planetary nature of these candidates. The outer planet, TOI-904 c, is the longest-period M dwarf exoplanet found by TESS, with an estimated equilibrium temperature of 217 K. As the three other validated planets with comparable host stars and orbital periods were observed by Kepler around much dimmer stars (Jmag > 12), TOI-904 c, orbiting a brighter star (Jmag = 9.6), is the coldest M dwarf planet easily accessible for atmospheric follow-up. Future mass measurements and transmission spectroscopy of the similarsized planets in this system could determine whether they are also similar in density and composition, suggesting a common formation pathway, or whether they have distinct origins. |
Keywords | Exoplanet systems ; Exoplanet detection methods; Exoplanet astronomy; Transit photometry; Mini Neptune; Cold Neptunes ; M dwarf stars |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 5101. Astronomical sciences |
Byline Affiliations | University of New Mexico, United States |
Center for Astrophysics Harvard and Smithsonian, United States | |
University of Geneva, Switzerland | |
University of Bern, Switzerland | |
NASA Ames Research Center, United States | |
Vanderbilt University, United States | |
Centre for Astrophysics | |
Stephen F. Austin State University, United States | |
Cerro Tololo Inter-American Observatory, Chile | |
George Mason University, United States | |
Massachusetts Institute of Technology, United States | |
Swarthmore College, United States | |
Brorfelde Observatory, Denmark | |
University of North Carolina at Chapel Hill, United States | |
Planetary Discoveries, United States | |
Princeton University, United States |
https://research.usq.edu.au/item/zq320/separated-twins-or-just-siblings-a-multiplanet-system-around-an-m-dwarf-including-a-cool-sub-neptune
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