An independent distance estimate to the AGB star R Sculptoris

摘要: Context. Distance measurements to astronomical objects are essential for understanding their intrinsic properties. For asymptotic giant branch (AGB) stars it is particularly difficult derive accurate distance estimates. Period-luminosity relationships rely on the correlation of different physical properties stars, while angular sizes and variability AGB make parallax inherently inaccurate. carbon star R Sculptoris, uncertain significantly affects interpretation observations regarding evolution stellar mass loss during after most recent thermal pulse. Aim. We aim provide a new, independent measurement reducing absolute uncertainty estimate this source. Methods. Scl semi-regular pulsating star, surrounded by thin shell dust gas created pulse ≈ 2000 years ago. The light scattered particles in at radius 19″. variation amount dust-scattered with same period amplitude ratio, but phase lag that depends size shell. measured observing from five epochs between June-December 2016. By polarised light, we imaged plane sky, removing any due geometrical effects. gives shell, together directly Sculptoris. Results. variations 40.0 ± 4.0 days. be 19.″1 0.″7. Combined, an Sculptoris 361 44 pc. Conclusions. independently determined 12%. estimated consistent previous estimates, one distances source date. In future, using polarised, may offer possibility measure reliable stars.