Year: 2026
Type: article
Abstract: We present a multi-sector TESS photometric and spectral energy distribution analysis of the eclipsing binary CPD–82 291 (RX J0853.1–8244). Eight TESS sectors reveal well-defined eclipses and substantial, changing out-of-eclipse modulation. The asymmetries are reproduced by different surface-brightness configurations at different epochs, consistent with strong and evolving stellar activity, although the fitted circular regions are not unique maps of individual starspots. A detached-binary light-curve model yields an orbital inclination of i ≃ 82 . ° 1 and a photometric mass ratio of q phot ≃ 0.464. Without a spectroscopic radial-velocity orbit, the mass ratio and absolute parameters are model dependent rather than dynamical measurements. Combining the light-curve geometry with the SED radius scale and Gaia distance gives R 1 ≃ 1.25 R ⊙ and R 2 ≃ 3.70 R ⊙ ; the corresponding model-inferred masses remain substantially less secure than the dimensionless light-curve parameters. The stellar photospheres reproduce the observed SED from the optical region through WISE W4, with no statistically significant mid-infrared excess. The only positive long-wavelength deviation is a low-significance 60 μ m measurement, while the 90 μ m result is an upper limit. A cool circumbinary-dust model can reproduce this tentative signal, but such a component is not required by the photometry, and its inferred mass and radial extent are non-unique and strongly model dependent. Evolutionary tracks place the primary close to the zero-age main sequence and the secondary well above the main-sequence locus. However, the absence of radial velocities and spectroscopic youth indicators, together with Gaia astrometry inconsistent with Chamaeleon I membership, prevents a secure pre-main-sequence classification. CPD–82 291 is therefore best regarded as an active eclipsing binary with uncertain evolutionary status and only a marginal far-infrared indication that could be reproduced by cool circumstellar material.
Authors: Volkan Bakış, Gökhan Yücel
Institution: Akdeniz University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,325
OpenAlex ID: W7204199288