Gentle curve of nova V1716 Sco noticed with NICER with 10 s time bins, on July 25, 2023 to August 30, 2023. Credit score: Wang et al., 2024.
Astronomers from China and Taiwan have noticed the nova eruption of V1716 Sco that occurred final yr, utilizing numerous X-ray and gamma-ray area observatories. Outcomes of the observational marketing campaign, offered June 27 on the preprint server arXiv, present important info concerning the evolution of this nova.
A nova is a star experiencing a sudden improve in brightness and slowly returning to its unique state, a course of that would final many months. Such an outburst is the results of the accretion course of in an in depth binary system containing a white dwarf and its companion.
V1716 Sco, also referred to as Nova Sco 2023, was detected when it erupted on April 20, 2023 at magnitude 8.0. Comply with-up observations of V1716 Sco spectroscopically confirmed it as a classical (Fe II) nova.
Now, a group of astronomers led by Huihui Wang of the Henan College of Science and Expertise in Luoyang, China, has investigated V1716 Sco in X-rays and gamma-ray bands. For this objective, they used NASA’s Swift, NuSTAR and Fermi spacecraft, in addition to the Neutron star Inside Composition Explorer (NICER) onboard the Worldwide House Station.
“We carried out a joint evaluation of NuSTAR, Swift, NICER, and Fermi-LAT observations of nova V1716 Sco,” the researchers wrote within the paper.
The observations discovered that the gamma-ray emission began a day after the optical eruption of V1716 Sco, with a check statistic (TS) worth of 70. The period of this gamma-ray exercise with a TS worth of above 4.0 lasted for 40 days. Furthermore, tougher X-ray emission was additionally noticed by Swift a day after the optical eruption.
Due to this fact, the findings make V1716 Sco the primary classical nova wherein the X-ray detection by Swift is concurrent with gamma-ray emission, and the fourth classical nova showcasing gamma-ray emission concurrent with tougher X-ray emission from NuSTAR information.
By analyzing the X-ray spectrum, the researchers discovered that the hardness ratio quickly decreased over time and the noticed emission entered the supersoft supply (SSS) part roughly 40 days after the nova eruption. Moreover, NICER information allowed the astronomers to detect a quasi-periodic oscillation (QPO) within the SSS part with a interval of 79.10 seconds.
Attempting to clarify the origin of the detected QPO, the authors of the paper level to the spin modulation of the white dwarf as probably the most believable speculation. Nonetheless, they famous that the interval of the modulations shouldn’t be secure with time. This will imply that the new spot area on the white dwarf’s floor might shift with time, or the periodic modulation might have originated from a special mechanism, comparable to a stellar oscillation.
Extra info:
H. -H. Wang et al, X-ray and gamma-ray examine for 2023 nova eruption of V1716 Sco, arXiv (2024). DOI: 10.48550/arxiv.2406.19233
Journal info:
arXiv
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Nova eruption of V1716 Sco inspected in X-rays and gamma rays (2024, July 4)
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