A Caltech Library Service

π Earth: A 3.14 day Earth-sized Planet from K2's Kitchen Served Warm by the SPECULOOS Team

Niraula, Prajwal and de Wit, Julien and Rackham, Benjamin V. and Ducrot, Elsa and Burdanov, Artem and Crossfield, Ian J. M. and Van Grootel, Valerie and Murray, Catriona and Garcia, Lionel J. and Alonso, Roi and Beard, Corey and Gomez Maqueo Chew, Yilen and Delrez, Laetitia and Demory, Brice-Olivier and Fulton, Benjamin J. and Gillon, Michaël and Günther, Maximilian N. and Howard, Andrew W. and Isaacson, Howard and Jehin, Emmanuel and Pedersen, Peter P. and Pozuelos, Francisco J. and Queloz, Didier and Rebolo-Lopez, Rafael and Sairam, Lalitha and Sebastian, Daniel and Thompson, Samantha and Triaud, Amaury H. M. J. (2020) π Earth: A 3.14 day Earth-sized Planet from K2's Kitchen Served Warm by the SPECULOOS Team. Astronomical Journal, 160 (4). Art. No. 172. ISSN 1538-3881. doi:10.3847/1538-3881/aba95f.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Submitted Version
Creative Commons Attribution.


Use this Persistent URL to link to this item:


We report on the discovery of a transiting Earth-sized (0.95 R_⊕) planet around an M3.5 dwarf star at 57 pc, EPIC 249631677. The planet has a period of ~3.14 days, i.e., ~π, with an installation of 7.45 S_⊕. The detection was made using publicly available data from K2's Campaign 15. We observed three additional transits with SPECULOOS Southern and Northern Observatories, and a stellar spectrum from Keck/HIRES, which allowed us to validate the planetary nature of the signal. The confirmed planet is well suited for comparative terrestrial exoplanetology. While exoplanets transiting ultracool dwarfs present the best opportunity for atmospheric studies of terrestrial exoplanets with the James Webb Space Telescope, those orbiting mid-M dwarfs within 100 pc such as EPIC 249631677b will become increasingly accessible with the next generation of observatories.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Niraula, Prajwal0000-0002-8052-3893
de Wit, Julien0000-0003-2415-2191
Rackham, Benjamin V.0000-0002-3627-1676
Ducrot, Elsa0000-0002-7008-6888
Burdanov, Artem0000-0001-9892-2406
Crossfield, Ian J. M.0000-0002-1835-1891
Van Grootel, Valerie0000-0003-2144-4316
Murray, Catriona0000-0001-8504-5862
Alonso, Roi0000-0001-8462-8126
Beard, Corey0000-0001-7708-2364
Gomez Maqueo Chew, Yilen0000-0002-7486-6726
Delrez, Laetitia0000-0001-6108-4808
Demory, Brice-Olivier0000-0002-9355-5165
Fulton, Benjamin J.0000-0003-3504-5316
Gillon, Michaël0000-0003-1462-7739
Günther, Maximilian N.0000-0002-3164-9086
Howard, Andrew W.0000-0001-8638-0320
Isaacson, Howard0000-0002-0531-1073
Jehin, Emmanuel0000-0001-8923-488X
Pozuelos, Francisco J.0000-0003-1572-7707
Queloz, Didier0000-0002-3012-0316
Triaud, Amaury H. M. J.0000-0002-5510-8751
Alternate Title:π Earth: a 3.14 days Earth-sized Planet from K2's Kitchen served warm by the SPECULOOS Team
Additional Information:© 2020 The American Astronomical Society. Received 2020 June 9; revised 2020 July 17; accepted 2020 July 23; published 2020 September 21. This project makes use of publicly available K2 data. P.N. would like to acknowledge funding for Kerr Fellowship and Elliot Fellowship at MIT. J.d.W. and MIT gratefully acknowledge financial support from the Heising-Simons Foundation, Dr. and Mrs. Colin Masson and Dr. Peter A. Gilman for Artemis, the first telescope of the SPECULOOS network situated in Tenerife, Spain. B.V.R. thanks the Heising-Simons Foundation for support. V.V.G. is a F.R.S.-FNRS Research Associate. M.G. and E.J. are F.R.S.-FNRS Senior Research Associates. This work was also partially supported by a grant from the Simons Foundation (PI: Queloz, grant number 327127), and funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007–2013) ERC Grant Agreement Number 336480, from the ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation, from the Balzan Prize Foundation, from F.R.S-FNRS (Research Project ID T010920F), from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation program (grant agreement No. 803193/BEBOP), and from a Leverhulme Trust Research Project Grant No. RPG-2018–418. Facilities: Keck:I (HIRES) - , Kepler - , MAST (HLSP - , K2) - , SNO - , SSO. - Software: astropy (Astropy Collaboration et al. 2013, 2018), batman (Kreidberg 2015), emcee (Foreman-Mackey et al. 2013), isochrones (Morton 2015), prose (L. J. Garcia et al. 2020, in preparation), SPOCK (D. Sebastian & M. Gillon 2020, in preparation), transitleastsquares (Hippke & Heller 2019), wōtan (Hippke et al. 2019).
Group:Astronomy Department, Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Heising-Simons Foundation51 Pegasi b Fellowship
Juan Carlos Torres FellowshipUNSPECIFIED
Massachusetts Institute of Technology (MIT)UNSPECIFIED
Fonds de la Recherche Scientifique (FNRS)T010920F
Simons Foundation327127
European Research Council (ERC)336480
Wallonia-Brussels FederationUNSPECIFIED
Balzan Prize FoundationUNSPECIFIED
European Research Council (ERC)803193
Leverhulme TrustRPG-2018-418
Subject Keywords:Exoplanet detection methods ; Transit photometry
Issue or Number:4
Classification Code:Unified Astronomy Thesaurus concepts: Exoplanet detection methods (489); Transit photometry (1709)
Record Number:CaltechAUTHORS:20200624-091105285
Persistent URL:
Official Citation:Prajwal Niraula et al 2020 AJ 160 172
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103986
Deposited By: Tony Diaz
Deposited On:24 Jun 2020 17:32
Last Modified:16 Nov 2021 18:27

Repository Staff Only: item control page