The double-degenerate, super-Chandrasekhar nucleus of the planetary nebula Henize 2–428.

Caption: Artist illustration of the central core of the planetary nebula Henize 2-428. Stars are not to scale. Credit: Gabriel Pérez, SMM (IAC).

Advertised on

01/01/2015

References

Nature 2015)doi:10.1038/nature14124

The planetary nebula (PN) stage is the ultimate fate of stars with mass 1 to 8 solar masses (M⊙). The origin of their complex morphologies is poorly understood, although several mechanisms involving binary interaction have been proposed. In close binary systems, the orbital separation is short enough for the primary star to overfill its Roche lobe as it expands during the Asymptotic Giant Branch (AGB) phase. The excess material ends up forming a common-envelope (CE) surrounding both stars. Drag forces would then result in the envelope being ejected into a bipolar PN whose equator is coincident with the orbital plane of the system. Systems in which both stars have ejected their envelopes and evolve towards the white dwarf (WD) stage are called double-degenerates. Here we report that Henize 2–428 has a double-degenerate core with a combined mass unambiguously above the Chandrasekhar limit of 1.4 M⊙. According to its short orbital period (4.2 hours) and total mass (1.76 M⊙), the system should merge in 700 million years, triggering a Type Ia supernova (SN Ia) event. This finding supports the double-degenerate, super-Chandrasekhar evolutionary channel for the formation of SNe Ia.

It may interest you

Research news

Chronology of our Galaxy from Gaia colour-magnitude diagram fitting (ChronoGal): II. Unveiling the formation and evolution of the kinematically selected Thick and Thin Discs

Research on the formation, origin, and evolution of the dichotomy between the thin and thick disk components of the Milky Way has been a major topic of study, as it is key to understanding how our Galaxy formed. However, this is not an easy task, since populations defined by their morphology or kinematics show a mixture of chemically distinct stellar populations. Age therefore becomes a fundamental parameter for understanding the evolution of the Galactic disk. Our goal is to derive the age and metallicity distributions of the thin and thick disks defined kinematically, in order to reveal

Advertised on

02/09/2026 - 22:44:10
Read more
Research news

MONOS: Multiplicity Of Northern O-type Spectroscopic systems: III. New orbits and Gaia–TESS analysis for ten SB2E systems

The most massive stars in the universe are often born and evolve in binary and multiple systems — that is, in pairs or groups bound by their mutual gravity. Understanding how they interact with each other is key to explaining everything from their formation to the impact they have on the galaxies they inhabit. The MONOS project (Multiplicity Of Northern O-type Spectroscopic systems) aims to study these systems in the northern sky, combining spectroscopic observations (which analyze light split into its component colors to measure stellar velocities and physical properties) with photometry

Advertised on

10/31/2025 - 10:44:24
Read more
Research news

The slow expansion of dark matter halos from cusp to core naturally produces extended stellar core-like distributions

Only a handful of observations truly constrain the nature of dark matter, which is why dozens of different physical models are still viable. Several of the most popular alternatives predict that dark matter halos slowly “thermalize” over time, gradually changing shape and expanding until they form a central region of nearly constant density -- a core. This transformation would not occur if the dark matter particles were completely collision-less, as assumed in the standard model. Therefore, the presence or absence of such a core provides a powerful way to distinguish between the standard

Advertised on

12/19/2025 - 10:01:55
Read more