Carbon dust in the evolved born-again planetary nebulae A 30 and A 78
We present an infrared (IR) characterization of the born-again planetary nebulae (PNe) A 30 and A 78 using IR images and spectra. We demonstrate that the carbon-rich dust in A 30 and A 78 is spatially coincident with the H-poor ejecta and coexists with hot X-ray-emitting gas up to distances of 50 ar...
| Published in: | Monthly Notices of the Royal Astronomical Society |
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| Main Authors: | , , , , , , , , |
| Other Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Oxford University Press
2021
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| Subjects: | |
| Online Access: | http://hdl.handle.net/10261/247831 https://doi.org/10.1093/mnras/stab593 |
| Summary: | We present an infrared (IR) characterization of the born-again planetary nebulae (PNe) A 30 and A 78 using IR images and spectra. We demonstrate that the carbon-rich dust in A 30 and A 78 is spatially coincident with the H-poor ejecta and coexists with hot X-ray-emitting gas up to distances of 50 arcsec from the central stars of PNe (CSPNe). Dust forms immediately after the born-again event and survives for 1000 yr in the harsh environment around the CSPN as it is destroyed and pushed away by radiation pressure and dragged by hydrodynamical effects. Spitzer IRS spectral maps showed that the broad spectral features at 6.4 and 8.0 μm, attributed to amorphous carbon formed in H-deficient environments, are associated with the disrupted disc around their CSPN, providing an optimal environment for charge exchange reactions with the stellar wind that produces the soft X-ray emission of these sources. Nebular and dust properties are modelled for A 30 with cloudy taking into account different carbonaceous dust species. Our models predict dust temperatures in the 40-230 K range, five times lower than predicted by previous works. Gas and dust masses for the born-again ejecta in A 30 are estimated to be Mgas=4.41+0.550.14× 10-3 M· and M dust=3.20+3.21-2.06× 10-3 M·, which can be used to estimate a total ejected mass and mass-loss rate for the born-again event of 7.61+3.76-2.20× 10-3 M· and M=(5-60)× 10-5 M· yr-1, respectively. Taking into account the carbon trapped into dust grains, we estimate that the C/O mass ratio of the H-poor ejecta of A 30 is larger than 1, which favours the very late thermal pulse model over the alternate hypothesis of a nova-like event. © 2021 The Author(s). The authors acknowledge funding by Direccion General de Asuntos del Personal Academico of the Universidad Nacional Autonoma de Mexico (DGAPA, UNAM) project IA100720. JAT thanks Fundacion Marcos Moshinsky (Mexico). VMAGG acknowledges support from the Programa de Becas posdoctorales funded by DGAPA, UNAM. JBRG, SED, and PJH thank Consejo Nacional deCiencias yTecnolog ' ia(CONACYT) Mexico for research student grants. MAGacknowledges support of the SpanishMinisterio de Ciencia, Innovacion y Universidades (MCIU) grant PGC2018-102184-B-I00. GRL acknowledges support from CONACYT (grant 263373) and PRODEP (Mexico). DAGH acknowledges support from the State Research Agency (AEI) of the Spanish Ministry of Science, Innovation and Universities (MCIU) and the European Regional Development Fund (FEDER) under grant AYA2017-88254-P. This study is based on observations made with the instruments NOTCam at the Nordic Optical Telescope (NOT) and CanariCam at the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, in the island of La Palma. NOT is owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku, and the University of Oslo, representing Denmark, Finland, and Norway, the University of Iceland, and Stockholm University. This work makes use of Spitzer IR observations, which was operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. This work is partially based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. This work has made extensive use of NASA's Astrophysics Data System. With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709. Peer reviewed |
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