9–10 Apr 2026
Monte Mario
Europe/Rome timezone

Determination of Classical Cepheids distances in the Magellanic Clouds using polarimetric analysis

10 Apr 2026, 14:40
20m
Sala Cimmino (Monte Mario)

Sala Cimmino

Monte Mario

Via del Parco Mellini, 84, 00136 Roma

Speaker

Erasmo Trentin (Istituto Nazionale di Astrofisica (INAF))

Description

Classical Cepheids (DCEPs) are the most important standard candles of the extragalactic distance scale thanks to the Leavitt Law, which is a relationship between period and luminosity (PL) of DCEPs.
Once calibrated using independent distances based on geometric methods such as trigonometric parallaxes, eclipsing binaries, and water masers, these relations constitute the first step in forming the cosmic distance scale, as they calibrate secondary distance indicators.
An alternative method of estimating distances is using a polarimetric analysis of light echoes produced by the dust nebula around long-period DCEPs.
In this talk, I will illustrate the scientific case and present a preliminary observational strategy for extending this technique to the Magellanic Clouds, already used as anchors of the cosmic distance scale, which host over 10,000 Classical Cepheids.
Current statistics indicate that more than 50 long-period DCEPs are promising candidates for polarimetric distance measurements. Geometric distances derived for these objects would provide robust results for the distance scale of the Large and Small Magellanic Clouds and, consequently, for the extragalactic distance ladder. Furthermore, the resulting absolute luminosities will offer valuable constraints on Cepheid pulsation and stellar evolution models.

Author

Erasmo Trentin (Istituto Nazionale di Astrofisica (INAF))

Presentation materials

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