Is there really a debris disc around $\zeta^2\,\mathrm{Reticuli}$ ?

V. Faramaz; G. Bryden; K. R. Stapelfeldt; M. Booth; A. Bayo; H. Beust; S. Casassus; J. Cuadra; A. Hales; A. M. Hughes; J. Olofsson; K. Y. L. Su; D. J. Wilner

doi:10.1093/mnras/sty2304

arXiv · 1809.00645

Is there really a debris disc around $\zeta^2\,\mathrm{Reticuli}$ ?

V. Faramaz·G. Bryden·K. R. Stapelfeldt·M. Booth·A. Bayo·H. Beust·S. Casassus·J. Cuadra·A. Hales·A. M. Hughes·J. Olofsson·K. Y. L. Su·D. J. Wilner

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Abstract

The presence of a debris disc around the Gyr-old solar-type star $\zeta^2\,\mathrm{Reticuli}$ was suggested by the $\mathit{Spitzer}$ infrared excess detection. Follow-up observations with $\mathit{Herschel}$/PACS revealed a double-lobed feature, that displayed asymmetries both in brightness and position. Therefore, the disc was thought to be edge-on and significantly eccentric. Here we present ALMA/ACA observations in Band 6 and 7 which unambiguously reveal that these lobes show no common proper motion with $\zeta^2\,\mathrm{Reticuli}$. In these observations, no flux has been detected around $\zeta^2\,\mathrm{Reticuli}$ that exceeds the $3\sigma$ levels. We conclude that surface brightness upper limits of a debris disc around $\zeta^2\,\mathrm{Reticuli}$ are $5.7\,\mathrm{\mu Jy/arcsec^2}$ at 1.3 mm, and $26\,\mathrm{\mu Jy/arcsec^2}$ at 870 microns. Our results overall demonstrate the capability of the ALMA/ACA to follow-up $\mathit{Herschel}$ observations of debris discs and clarify the effects of background confusion.

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V. Faramaz, G. Bryden, K. R. Stapelfeldt, M. Booth, A. Bayo, H. Beust, S. Casassus, J. Cuadra, A. Hales, A. M. Hughes, J. Olofsson, K. Y. L. Su, D. J. Wilner. 2018-09-03. Is there really a debris disc around $\zeta^2\,\mathrm{Reticuli}$ ?. https://doi.org/10.1093/mnras/sty2304

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