JWST Imaging of Earendel, the Extremely Magnified Star at Redshift z = 6.2

Brian Welch*, Dan Coe, Erik Zackrisson, S. E. de Mink, Swara Ravindranath, Jay Anderson, Gabriel Brammer, Larry Bradley, Jinmi Yoon, Patrick Kelly, Jose M. Diego, Rogier Windhorst, Adi Zitrin, Paola Dimauro, Yolanda Jiménez-Teja, Abdurro’uf, Mario Nonino, Ana Acebron, Felipe Andrade-Santos, Roberto J. AvilaMatthew B. Bayliss, Alex Benítez, Tom Broadhurst, Rachana Bhatawdekar, Maruša Bradač, Gabriel B. Caminha, Wenlei Chen, Jan Eldridge, Ebraheem Farag, Michael Florian, Brenda Frye, Seiji Fujimoto, Sebastian Gomez, Alaina Henry, Tiger Y.Y. Hsiao, Taylor A. Hutchison, Bethan L. James, Meridith Joyce, Intae Jung, Gourav Khullar, Rebecca L. Larson, Guillaume Mahler, Nir Mandelker, Stephan McCandliss, Takahiro Morishita, Rosa Newshore, Colin Norman, Kyle O’Connor, Pascal A. Oesch, Masamune Oguri, Masami Ouchi, Marc Postman, Jane R. Rigby, Russell E. Ryan, Soniya Sharma, Keren Sharon, Victoria Strait, Louis Gregory Strolger, F. X. Timmes, Sune Toft, Michele Trenti, Eros Vanzella, Anton Vikaeus

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


The gravitationally lensed star WHL 0137-LS, nicknamed Earendel, was identified with a photometric redshift z phot = 6.2 ± 0.1 based on images taken with the Hubble Space Telescope. Here we present James Webb Space Telescope (JWST) Near Infrared Camera images of Earendel in eight filters spanning 0.8-5.0 μm. In these higher-resolution images, Earendel remains a single unresolved point source on the lensing critical curve, increasing the lower limit on the lensing magnification to μ > 4000 and restricting the source plane radius further to r < 0.02 pc, or ∼4000 au. These new observations strengthen the conclusion that Earendel is best explained by an individual star or multiple star system and support the previous photometric redshift estimate. Fitting grids of stellar spectra to our photometry yields a stellar temperature of T eff ≃ 13,000-16,000 K, assuming the light is dominated by a single star. The delensed bolometric luminosity in this case ranges from log ( L ) = 5.8 to 6.6 L , which is in the range where one expects luminous blue variable stars. Follow-up observations, including JWST NIRSpec scheduled for late 2022, are needed to further unravel the nature of this object, which presents a unique opportunity to study massive stars in the first billion years of the universe.

Original languageAmerican English
Article numberL1
JournalAstrophysical Journal Letters
Issue number1
StatePublished - 1 Nov 2022

Bibliographical note

Funding Information:
This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope (JWST). The data were obtained from the Mikulski Archive for Space Telescopes (MAST) at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program JWST GO 2282.

Funding Information:
E.Z. acknowledges support from the Swedish National Space Board. M.B. acknowledges support from the Slovenian national research agency ARRS through grant N1-0238. A.Z. acknowledges support by grant No. 2020750 from the United States–Israel Binational Science Foundation (BSF) and grant No. 2109066 from the United States National Science Foundation (NSF) and by the Ministry of Science & Technology, Israel. M.T. acknowledges support by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) through project No. CE170100013. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant No. 140. J.M.D. acknowledges the support of projects PGC2018-101814-B-100 and MDM-2017-0765. Y.J.-T. acknowledges financial support from the European Union’s Horizon 2020 research and innovation program under Marie Skłodowska-Curie grant agreement No. 898633, the MSCA IF Extensions Program of the Spanish National Research Council (CSIC), and the State Agency for Research of the Spanish MCIU through the Center of Excellence Severo Ochoa award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). P.A.O. acknowledges support by the Swiss National Science Foundation through project grant 200020_207349.

Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.


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