Snowflakes in a Furnace: Formation of CO and Dust in a Recurrent Nova Eruption

Banerjee, D. P. K.; Woodward, C. E.; Joshi, V.; Evans, A.; Walter, F. M.; Marion, G. H.; Hsiao, E. Y.; Ashok, N. M.; Gehrz, R. D.; Starrfield, S.

Abstract

We report the detection of carbon monoxide (CO) and dust, formed under hostile conditions, in recurrent nova V745 Sco about 8.7 days after its 2014 outburst. The formation of molecules or dust has not been recorded previously in the ejecta of a recurrent nova. The mass and temperature of the CO and dust are estimated to be TCO = 2250 ± 250 K, MCO = (1–5) × 10−8M⊙, and Tdust = 1000 ± 50 K, Mdust ∼ 10−8–10−9M⊙, respectively. At the time of their detection, the shocked gas was at a high temperature of ∼107 K as evidenced by the presence of coronal lines. The ejecta were simultaneously irradiated by a large flux of soft X-ray radiation from the central white dwarf. Molecules and dust are not expected to form and survive in such harsh conditions; they are like snowflakes in a furnace. However, it has been posited in other studies that, as the nova ejecta plow through the red giant's wind, a region exists between the forward and reverse shocks that is cool, dense and clumpy where the dust and CO could likely form. We speculate that this site may also be a region of particle acceleration, thereby contributing to the generation of γ-rays.

Citation

Banerjee, D. P. K., Woodward, C. E., Joshi, V., Evans, A., Walter, F. M., Marion, G. H., …Starrfield, S. (2023). Snowflakes in a Furnace: Formation of CO and Dust in a Recurrent Nova Eruption. Astrophysical Journal Letters, 954(1), Article L16. https://doi.org/10.3847/2041-8213/acf0c4

• Journal Article Type: Article
• Acceptance Date: Aug 4, 2023
• Online Publication Date: Aug 31, 2023
• Publication Date: Sep 1, 2023
• Deposit Date: Feb 9, 2024
• Journal: The Astrophysical Journal Letters
• Print ISSN: 2041-8205
• Electronic ISSN: 2041-8213
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 954
• Issue: 1
• Article Number: L16
• DOI: https://doi.org/10.3847/2041-8213/acf0c4
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Publisher URL: https://iopscience.iop.org/article/10.3847/2041-8213/acf0c4
• Additional Information: Article Title: Snowflakes in a Furnace: Formation of CO and Dust in a Recurrent Nova Eruption; Journal Title: The Astrophysical Journal Letters; Article Type: paper; Copyright Information: © 2023. The Author(s). Published by the American Astronomical Society.; Date Received: 2023-06-28; Date Accepted: 2023-08-04; Online publication date: 2023-08-31