DISCOVERY OF FAST, LARGE-AMPLITUDE OPTICAL VARIABILITY OF V648 Car (=SS73-17)
- Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Vicuna Mackenna 4860, 7820436 Macul, Santiago (Chile)
- Sydney Institute for Astronomy, The University of Sydney, 44-70 Rosehill Street, Redfern, NSW 2016 (Australia)
- Departamento de Fisica Teorica e Experimental, Universidade Federal do Rio Grande do Norte, Campus Universitario, Lagoa Nova, CEP 59078-970 Natal/RN (Brazil)
- INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, via Gobetti 101, I-40129 Bologna (Italy)
We report on the discovery of large-amplitude flickering from V648 Car (= SS73-17), a poorly studied object listed among the very few hard X-ray-emitting symbiotic stars. We performed millimagnitude precision optical photometry with the Swope Telescope at the Las Campanas Observatory, Chile, and found that V648 Car shows large U-band variability over timescales of minutes. To our knowledge, it exhibits some of the largest flickering of a symbiotic star ever reported. Our finding supports the hypothesis that symbiotic white dwarfs producing hard X-rays are predominantly powered by accretion, rather than quasi-steady nuclear burning, and have masses close to the Chandrasekhar limit. No significant periodicity is evident from the flickering light curve. The All Sky Automated Survey long-term V light curve suggests the presence of a tidally distorted giant accreting via Roche lobe overflow, and a binary period of {approx}520 days. On the basis of the outstanding physical properties of V648 Car as hinted at by its fast and long-term optical variability, as well as by its nature as a hard X-ray emitter, we therefore call for simultaneous follow-up observations in different bands, ideally combined with time-resolved optical spectroscopy.
- OSTI ID:
- 22078561
- Journal Information:
- Astrophysical Journal Letters, Vol. 756, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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