Little Red Dots as Intermediate Mass, Super-Eddington Engines: Insights from Type IIn Supernovae and The 1837-1856 Great Eruption of η Carinae
11 affiliations
- 1Institute for Astronomy , University of Hawai'i , 2680 Woodlawn Drive , Honolulu , HI 96822 , USA
- 2MIT Kavli Institute for Astrophysics and Space Research , 70 Vassar Street , Cambridge , MA 02139 , USA
- 3Institute of Science and Technology Austria (ISTA) , Am Campus 1 , 3400 Klosterneuburg , Austria
- 4Department of Astronomy & Astrophysics , University of Chicago , 5640 S Ellis Avenue , Chicago , IL 60637 , USA
- 5Kavli Institute for Cosmological Physics , University of Chicago , Chicago IL 60637 , USA
- 6Cosmic Frontier Center , The University of Texas at Austin , Austin , TX 78712 , USA
- 7Department of Astronomy , The University of Texas at Austin , Austin , TX , USA
- 8Institute for Astronomy , University of Hawai'i , 640 N Aohoku Place , Hilo , HI 96720 , USA
- 9Department of Astrophysical Sciences , Princeton University , Princeton , NJ 08544 , USA
- 10Steward Observatory , University of Arizona , 933 North Cherry Avenue , Tucson , AZ 85721-0065 , USA
- 11Department of Astronomy , University of Geneva , Chemin Pegasi 51 , 1290 Versoix , Switzerland and
Abstract
JWST's Little Red Dots (LRDs) display a unique constellation of features that do not occur simultaneously in any other class of galaxies or AGN. Here we observe that many of these features find parallels in the 19th century Great Eruption (GE) of η Carinae and a sub-class of supernovae (Type IIn). Drawing on these stellar phenomena -- outflows trapped by dense circumstellar gas envelopes -- we sketch a possible scenario for LRDs. Outflows from the central engine produce an enshrouding envelope of gas that may be thought of as a slow wind. This dense wind and its enormous extent produce an opacity so high that a pseudo-photosphere forms within the wind, obscuring the central engine and manifesting as a blackbody-like continuum. Radiation from the buried engine powers the system. The engine may also launch fast winds that crash into the existing envelope to generate shocks. Lines form within the wind above the photosphere -- electron scattering and absorption in the clumpy (ionized + neutral) medium account for broad wings and P-Cygni cores. A key implication is that inferences of ``overmassive black holes" may be interpreting this wind-like physics as a virial broad-line region. We propose an escape velocity argument to constrain the mass of the engine, which yields M<105 M⊙ for the typical LRD. The lack of variability and low surface gravity of the photosphere provide further support for intermediate mass (M≈103−6 M⊙), but very luminous super-Eddington (Lbol/Ledd≳5) systems harboring a supermassive star or intermediate mass black hole. Paralleling the evolution of IIn SNe, dust production in the envelope may mark the beginnings of classical AGN. This paper explores a possible self-consistent explanation for the entire life-cycle of LRDs, from their enshrouding in dense gas to their fates as seeds of massive black holes.
Related
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BibTeX
@misc{naidu2026little,
title = {{Little Red Dots as Intermediate Mass, Super-Eddington Engines: Insights from Type IIn Supernovae and The 1837-1856 Great Eruption of $η$ Carinae}},
author = {Rohan P. Naidu and Jorryt Matthee and Anna de Graaff and Alberto Torralba and Chris Ashall and Harley Katz and John Chisholm and Gabriel Brammer and Luc Dessart and Anna–Christina Eilers and Raphael E. Hviding and David O. Jones and Vasily Kokorev and Joel Leja and Hanpu Liu and Zhaoran Liu and Devesh Nandal and Pascal A. Oesch and C. L. Ransome and Robert A. Simcoe and Wendy Q. Sun and Andrea Weibel and Mengyuan Xiao},
howpublished = {arXiv (Cornell University)},
year = {2026},
month = jun,
doi = {10.48550/arxiv.2606.30711},
url = {https://arxiv.org/abs/2606.30711},
note = {CC BY},
}
RIS
TY - UNPB
TI - Little Red Dots as Intermediate Mass, Super-Eddington Engines: Insights from Type IIn Supernovae and The 1837-1856 Great Eruption of η Carinae
AU - Rohan P. Naidu
AU - Jorryt Matthee
AU - Anna de Graaff
AU - Alberto Torralba
AU - Chris Ashall
AU - Harley Katz
AU - John Chisholm
AU - Gabriel Brammer
AU - Luc Dessart
AU - Anna–Christina Eilers
AU - Raphael E. Hviding
AU - David O. Jones
AU - Vasily Kokorev
AU - Joel Leja
AU - Hanpu Liu
AU - Zhaoran Liu
AU - Devesh Nandal
AU - Pascal A. Oesch
AU - C. L. Ransome
AU - Robert A. Simcoe
AU - Wendy Q. Sun
AU - Andrea Weibel
AU - Mengyuan Xiao
PY - 2026
DA - 2026/06/29
PB - arXiv (Cornell University)
DO - 10.48550/arxiv.2606.30711
UR - https://arxiv.org/abs/2606.30711
AB - JWST's Little Red Dots (LRDs) display a unique constellation of features that do not occur simultaneously in any other class of galaxies or AGN. Here we observe that many of these features find parallels in the 19th century Great Eruption (GE) of η Carinae and a sub-class of supernovae (Type IIn). Drawing on these stellar phenomena -- outflows trapped by dense circumstellar gas envelopes -- we sketch a possible scenario for LRDs. Outflows from the central engine produce an enshrouding envelope of gas that may be thought of as a slow wind. This dense wind and its enormous extent produce an opacity so high that a pseudo-photosphere forms within the wind, obscuring the central engine and manifesting as a blackbody-like continuum. Radiation from the buried engine powers the system. The engine may also launch fast winds that crash into the existing envelope to generate shocks. Lines form within the wind above the photosphere -- electron scattering and absorption in the clumpy (ionized + neutral) medium account for broad wings and P-Cygni cores. A key implication is that inferences of ``overmassive black holes" may be interpreting this wind-like physics as a virial broad-line region. We propose an escape velocity argument to constrain the mass of the engine, which yields M<10^5 M_⊙ for the typical LRD. The lack of variability and low surface gravity of the photosphere provide further support for intermediate mass (M≈10^3−6 M_⊙), but very luminous super-Eddington (L_bol/L_edd≳5) systems harboring a supermassive star or intermediate mass black hole. Paralleling the evolution of IIn SNe, dust production in the envelope may mark the beginnings of classical AGN. This paper explores a possible self-consistent explanation for the entire life-cycle of LRDs, from their enshrouding in dense gas to their fates as seeds of massive black holes.
SN - 2331-8422
ER -