EK Cha b: multi-tracer detection of a protoplanet candidate in a gas-rich environment
Abstract
Despite sustained community efforts and advances in instrumentation and high-contrast imaging, the search for protoplanets remains difficult, with only two widely accepted systems to date in Class II systems (PDS 70 and WISPIT 2). Here we present the detection of EK Cha b, a new protoplanet candidate, identified through CO emission, millimeter continuum and 0.82 micron broadband photometry, linked to EK Cha, a young late-type M star. The detection of a new protoplanet candidate offers an additional opportunity to advance our understanding of planet formation. By exploiting the wealth of archival data available for nearby star-forming regions, we aim to place EK Cha b in context, characterize its properties, and motivate future campaigns targeting similar systems. We analyzed high-spatial-resolution archival observations of EK Cha from HST, VLT/NACO, VLT/MUSE, and ALMA. We searched for EK Cha b in broadband continuum and gas tracers, reporting the measured flux with uncertainties, and upper limits for non-detections. EK Cha b shows a spectrally-resolved footprint that matches the CO J=2--1 emission, together with 0.82 micron and millimeter continuum emission. EK Cha b is spectrally resolved in CO J=2--1 emission, kinematically consistent with a circumplanetary disk. Best fits from evolutionary models place EK Cha b as a planetary mass companion, although deeper observations are required to fully confirm its nature. Although giant planets are uncommon around M dwarfs, these stars host the highest planet occurrence rate while remaining severely underrepresented in protoplanet searches. EK Cha b demonstrates that such systems are now within reach, and the advent of extremely large telescopes and improved high-contrast imaging -- where the lower host luminosity relaxes the required contras-- will open this overlooked regime to systematic exploration.
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BibTeX
@misc{alarcon2026multitracer,
title = {{EK Cha b: multi-tracer detection of a protoplanet candidate in a gas-rich environment}},
author = {Felipe Alarcón and C. Swastik and Stefano Facchini and Edwin A. Bergin and Gabriele Cugno},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.10701},
eprint = {2610.10701},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.10701},
note = {CC BY-SA 4.0},
}
RIS
TY - UNPB
TI - EK Cha b: multi-tracer detection of a protoplanet candidate in a gas-rich environment
AU - Felipe Alarcón
AU - C. Swastik
AU - Stefano Facchini
AU - Edwin A. Bergin
AU - Gabriele Cugno
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.10701
UR - https://arxiv.org/abs/2610.10701
AB - Despite sustained community efforts and advances in instrumentation and high-contrast imaging, the search for protoplanets remains difficult, with only two widely accepted systems to date in Class II systems (PDS 70 and WISPIT 2). Here we present the detection of EK Cha b, a new protoplanet candidate, identified through CO emission, millimeter continuum and 0.82 micron broadband photometry, linked to EK Cha, a young late-type M star. The detection of a new protoplanet candidate offers an additional opportunity to advance our understanding of planet formation. By exploiting the wealth of archival data available for nearby star-forming regions, we aim to place EK Cha b in context, characterize its properties, and motivate future campaigns targeting similar systems. We analyzed high-spatial-resolution archival observations of EK Cha from HST, VLT/NACO, VLT/MUSE, and ALMA. We searched for EK Cha b in broadband continuum and gas tracers, reporting the measured flux with uncertainties, and upper limits for non-detections. EK Cha b shows a spectrally-resolved footprint that matches the CO J=2--1 emission, together with 0.82 micron and millimeter continuum emission. EK Cha b is spectrally resolved in CO J=2--1 emission, kinematically consistent with a circumplanetary disk. Best fits from evolutionary models place EK Cha b as a planetary mass companion, although deeper observations are required to fully confirm its nature. Although giant planets are uncommon around M dwarfs, these stars host the highest planet occurrence rate while remaining severely underrepresented in protoplanet searches. EK Cha b demonstrates that such systems are now within reach, and the advent of extremely large telescopes and improved high-contrast imaging -- where the lower host luminosity relaxes the required contras-- will open this overlooked regime to systematic exploration.
ER -