The First Habitable-zone Earth-sized Planet from TESS. II. Spitzer Confirms TOI-700 d

Joseph E. Rodriguez, Andrew Vanderburg, Sebastian Zieba, Laura Kreidberg, Caroline V. Morley, Jason D. Eastman, Stephen R. Kane, Alton Spencer, Samuel N. Quinn, Ryan Cloutier, Chelsea X. Huang, Karen A. Collins, Andrew W. Mann, Emily Gilbert, Joshua E. Schlieder, Elisa V. Quintana, Thomas Barclay, Gabrielle Suissa, Ravi kumar Kopparapu, Courtney D. DressingGeorge R. Ricker, Roland K. Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Zachory Berta-Thompson, Patricia T. Boyd, David Charbonneau, Douglas A. Caldwell, Eugene Chiang, Jessie L. Christiansen, David R. Ciardi, Knicole D. Colón, John Doty, Tianjun Gan, Natalia Guerrero, Maximilian N. Günther, Eve J. Lee, Alan M. Levine, Eric Lopez, Philip S. Muirhead, Elisabeth Newton, Mark E. Rose, Joseph D. Twicken, Jesus Noel Villaseñor

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


We present Spitzer 4.5 μm observations of the transit of TOI-700 d, a habitable-zone Earth-sized planet in a multiplanet system transiting a nearby M-dwarf star (TIC 150428135, 2MASS J06282325-6534456). TOI-700 d has a radius of 1.144-0.061+0.062R⊕ and orbits within its host star's conservative habitable zone with a period of 37.42 days (T eq ∼ 269 K). TOI-700 also hosts two small inner planets (R b = 1.037-0.064+0.065R⊕and R c = 2.65-0.15+0.16R⊕) with periods of 9.98 and 16.05 days, respectively. Our Spitzer observations confirm the Transiting Exoplanet Survey Satellite (TESS) detection of TOI-700 d and remove any remaining doubt that it is a genuine planet. We analyze the Spitzer light curve combined with the 11 sectors of TESS observations and a transit of TOI-700 c from the LCOGT network to determine the full system parameters. Although studying the atmosphere of TOI-700 d is not likely feasible with upcoming facilities, it may be possible to measure the mass of TOI-700 d using state-of-the-art radial velocity (RV) instruments (expected RV semiamplitude of ∼70 cm s-1).

Original languageEnglish (US)
Article numberaba4b3
JournalAstronomical Journal
Issue number3
StatePublished - Sep 2020

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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