V1047 Cen: The first Z And-type outburst observed in the classical nova binary (2503.14994v1)

Abstract: In 2019, the classical nova V1047 Cen experienced an unusual outburst, the nature of which has not yet been clearly determined. In this paper, we show that the 2019 V1047~Cen outburst is of Z And-type -- a type that is characteristic and has so far been observed only in symbiotic binaries. We support our claim by modeling the near-ultraviolet to near-infrared spectral energy distribution, which revealed a close similarity between the fundamental parameters and the mass-loss rate of the burning white dwarf during the 2019 V1047 Cen outburst and those measured during Z And-type outbursts in symbiotic stars. All parameters are in agreement with the theoretical prediction when the accretion rate exceeds the stable burning limit for white dwarfs with masses less than 0.7 solar units. Our analysis showed that after a nova explosion, the Z And-type outburst can occur not only in symbiotic binaries but also in short-period cataclysmic variables, when the accretion-powered system changes to a nuclear-powered one, as a consequence of the donor's reaction to the nova explosion. Such a development promotes the production of Type Ia supernovae.

Z And-Type Outburst in Classical Nova V1047 Cen

The paper presents a detailed paper of the 2019 outburst of V1047 Cen, a classical nova, manifesting features analogous to the Z And-type outbursts previously observed only in symbiotic stars. This research provides a comprehensive spectral energy distribution (SED) analysis from the near-ultraviolet to near-infrared, affirming the characteristics of the observed outburst as consistent with those of Z And-type events.

Summary of the Findings

In 2019, V1047 Cen exhibited an outburst atypical for classical novae, traditionally seen in symbiotic stars undergoing Z And-type phenomena. Through modeling the spectral energy distribution, the researchers establish the presence of a nuclear-burning white dwarf during the outburst. Key parameters such as the luminosity, mass-loss rates, and temperature suggest conditions ideal for a Z And-type outburst, characterized by excessive accretion rates surpassing the stable burning threshold.

1. Spectral Analysis: The paper covers spectral energy distribution analysis across multiple wavelengths (near-ultraviolet to near-infrared) to capture the outburst's intrinsic characteristics. It discusses how the SED models confirm the elevated luminosity and mass-loss rates akin to those in symbiotic stars’ Z And-type events.
2. Physical Parameters: Fundamental parameters during the outburst included luminosities reaching several times $10^{37}$ erg/s, effective radii indicating expanded stellar envelopes, and temperatures around 150,000 to 190,000 K. These parameters mirror those of white dwarfs in symbiotic systems during Z And-type outbursts.
3. Mass-Transfer Dynamics: The research elaborates on how post-nova dynamics can facilitate the transition to a Z And-type outburst, particularly emphasizing how donor star reactions to nova explosions can enhance accretion rates, shifting systems from accretion-powered to nuclear-powered states.
4. Implications for Evolution: The transition observed in V1047 Cen is noted to potentially expedite the pathway to Type Ia supernovae due to sustained and enhanced mass accretion onto the white dwarf component.

Implications and Future Prospects

The occurrence of Z And-type outbursts in classical nova binaries like V1047 Cen broadens the understanding of white dwarf accretion dynamics beyond symbiotic stars. This finding is pivotal for re-evaluating models of nova evolution pathways and their contributions to Type Ia supernovae phenomena. Theoretically, this could suggest varying evolutionary time scales in cataclysmic variables compared to symbiotic systems, necessitating exploration into donor star characteristics and accretion mechanism efficiencies.

Future research could explore the population statistics of classical novae undergoing atypical outbursts, potentially revising current understandings of nova outburst classifications. Furthermore, investigating these systems could also refine the mass-loss processes and accretion dynamics critical to accurately predicting white dwarf runaway scenarios.

In summary, this paper highlights the critical intersection of observational astrophysics with theoretical predictions, extending our comprehension of accretion physics and outburst phenomena in various star systems.