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arXiv · 1901.00051

TESS delivers its first Earth-sized planet and a warm sub-Neptune

Diana Dragomir·Johanna Teske·Maximilian N. Gunther·Damien Ségransan·Jennifer A. Burt·Chelsea X. Huang·Andrew Vanderburg·Elisabeth Matthews·Xavier Dumusque·Keivan G. Stassun·Joshua Pepper·George R. Ricker·Roland Vanderspek·David W. Latham·Sara Seager·Joshua N. Winn·Jon M. Jenkins·Thomas Beatty·François Bouchy·Timothy M. Brown·R. Paul Butler·David R. Ciardi·Jeffrey D. Crane·Jason D. Eastman·Luca Fossati·Jim Francis·Benjamin J. Fulton·B. Scott Gaudi·Robert F. Goeke·David James·Todd C. Klaus·Rudolf B. Kuhn·Christophe Lovis·Michael B. Lund·Scott McDermott·Martin Paegert·Francesco Pepe·Joseph E. Rodriguez·Lizhou Sha·Stephen A. Shectman·Avi Shporer·Robert J. Siverd·Aylin Garcia Soto·Daniel J. Stevens·Joseph D. Twicken·Stéphane Udry·Steven Villanueva Jr.·Sharon X. Wang·Bill Wohler·Xinyu Yao·Zhuchang Zhan
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Abstract

The future of exoplanet science is bright, as TESS once again demonstrates with the discovery of its longest-period confirmed planet to date. We hereby present HD 21749b (TOI 186.01), a sub-Neptune in a 36-day orbit around a bright (V = 8.1) nearby (16 pc) K4.5 dwarf. TESS measures HD21749b to be 2.61$^{+0.17}_{-0.16}$ $R_{\oplus}$, and combined archival and follow-up precision radial velocity data put the mass of the planet at $22.7^{+2.2}_{-1.9}$ $M_{\oplus}$. HD 21749b contributes to the TESS Level 1 Science Requirement of providing 50 transiting planets smaller than 4 $R_{\oplus}$ with measured masses. Furthermore, we report the discovery of HD 21749c (TOI 186.02), the first Earth-sized ($R_p = 0.892^{+0.064}_{-0.058} R_{\oplus}$) planet from TESS. The HD21749 system is a prime target for comparative studies of planetary composition and architecture in multi-planet systems.

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Diana Dragomir, Johanna Teske, Maximilian N. Gunther, Damien Ségransan, Jennifer A. Burt, Chelsea X. Huang, Andrew Vanderburg, Elisabeth Matthews, Xavier Dumusque, Keivan G. Stassun, Joshua Pepper, George R. Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Thomas Beatty, François Bouchy, Timothy M. Brown, R. Paul Butler, David R. Ciardi, Jeffrey D. Crane, Jason D. Eastman, Luca Fossati, Jim Francis, Benjamin J. Fulton, B. Scott Gaudi, Robert F. Goeke, David James, Todd C. Klaus, Rudolf B. Kuhn, Christophe Lovis, Michael B. Lund, Scott McDermott, Martin Paegert, Francesco Pepe, Joseph E. Rodriguez, Lizhou Sha, Stephen A. Shectman, Avi Shporer, Robert J. Siverd, Aylin Garcia Soto, Daniel J. Stevens, Joseph D. Twicken, Stéphane Udry, Steven Villanueva Jr., Sharon X. Wang, Bill Wohler, Xinyu Yao, Zhuchang Zhan. 2018-12-31. TESS delivers its first Earth-sized planet and a warm sub-Neptune. https://doi.org/10.3847/2041-8213%2Fab12ed

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