Two Earth-size Planets and an Earth-size Candidate Transiting the nearby Star HD 101581 * * This paper includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile
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Author
Kunimoto, Michelle
Lin, Zifan
Millholland, Sarah
Venner, Alexander
Hinkel, Natalie R.
Shporer, Avi
Vanderburg, Andrew
Bailey, Jeremy
Brahm, Rafael
Burt, Jennifer A.
Butler, R. Paul
Carter, Brad
Ciardi, David R.
Collins, Karen A.
Collins, Kevin I.
Colón, Knicole D.
Crane, Jeffrey D.
Daylan, Tansu
Díaz, Matías R.
Doty, John P.
Feng, Fabo
Guenther, Eike W.
Horner, Jonathan
Howell, Steve B.
Janik, Jan
Jones, Hugh R. A.
Kabáth, Petr
Kanodia, Shubham
Littlefield, Colin
Osborn, Hugh P.
O’Toole, Simon
Paegert, Martin
Pintr, Pavel
Schwarz, Richard P.
Shectman, Steve
Srdoc, Gregor
Stassun, Keivan G.
Teske, Johanna K.
Twicken, Joseph D.
Vanzi, Leonardo
Wang, Sharon X.
Wittenmyer, Robert A.
Jenkins, Jon M.
Ricker, George R.
Seager, Sara
Winn, Joshua
Attention
2299/28617
Abstract
We report the validation of multiple planets transiting the nearby (d = 12.8 pc) K5V dwarf HD 101581 (GJ 435, TOI–6276, TIC 397362481). This system consists of at least two Earth-size planets whose orbits are near a mutual 4:3 mean-motion resonance, HD 101581 b ( Rp=0.956−0.061+0.063R⊕ , P = 4.47 days) and HD 101581c ( Rp=0.990−0.070+0.070R⊕ , P = 6.21 days). Both planets were discovered in Sectors 63 and 64 TESS observations and statistically validated with supporting ground-based follow-up. We also identify a signal that probably originates from a third transiting planet, TOI-6276.03 ( Rp=0.982−0.098+0.114R⊕ , P = 7.87 days). These planets are remarkably uniform in size and their orbits are evenly spaced, representing a prime example of the “peas-in-a-pod” architecture seen in other compact multiplanet systems. At V = 7.77, HD 101581 is the brightest star known to host multiple transiting planets smaller than 1.5 R ⊕. HD 101581 is a promising system for atmospheric characterization and comparative planetology of small planets.