JWST imaging of the closest globular clusters—I. Possible infrared excess among white dwarfs in NGC 6397

Bedin, LR, Nardiello, D, Salaris, M, Libralato, M, Bergeron, P, Burgasser, AJ, Apai, D, Griggio, M, Scalco, M, Anderson, J, Gerasimov, R and Bellini, A (2024) JWST imaging of the closest globular clusters—I. Possible infrared excess among white dwarfs in NGC 6397. Astronomische Nachrichten - Astronomical Notes. ISSN 0004-6337

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Abstract

We present James Webb Space Telescope observations of the globular cluster NGC 6397 and use them to extend to infrared wavelengths the characterization of the cluster's entire white dwarf (WD) cooling sequence (CS). The data allows us to probe fundamental astrophysical WD properties and to search for evidence in their colors for (or against) the existence of ancient planetary systems. The existing archival Hubble Space Telescope imaging data obtained (Formula presented.) years ago reach ultra-deep optical magnitudes ((Formula presented.)) and allow us to derive a near-perfect separation between field and cluster members. We detect an apparent split in the lower part of the WD CS of NGC 6397. The red part of the WD CS, containing about 25% of the total, exhibits significant IR-excess of up to (Formula presented.) mag. These infrared excesses require both theoretical and observational follow-ups to confirm their veracity and to ascertain their true nature.

Item Type:	Article
Additional Information:	This is the peer reviewed version of the following article: Bedin, L. R., Nardiello, D., Salaris, M., et al. 2024, Astron. Nachr., e20240039. https://doi.org/10.1002/asna.20240039, which has been published in final form at https://doi.org/10.1002/asna.20240039. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited
Uncontrolled Keywords:	0201 Astronomical and Space Sciences; Astronomy & Astrophysics
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	Wiley
Date of acceptance:	2 May 2025
Date of first compliant Open Access:	27 May 2025
Date Deposited:	10 Jun 2024 12:34
Last Modified:	27 May 2025 08:00
DOI or ID number:	10.1002/asna.20240039
URI:	https://researchonline.ljmu.ac.uk/id/eprint/23471

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