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| Main Authors: | , , , , , , , |
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| Format: | Preprint |
| Published: |
2026
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2604.24991 |
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| _version_ | 1866915962050052096 |
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| author | Casassus, Simon Carcamo, Miguel Dominguez-Jamett, Oriana Aoyama, Yuhiko Marleau, Gabriel-Dominique Chrenko, Ondrej Liu, Hauyu Baobab Ercolano, Barbar |
| author_facet | Casassus, Simon Carcamo, Miguel Dominguez-Jamett, Oriana Aoyama, Yuhiko Marleau, Gabriel-Dominique Chrenko, Ondrej Liu, Hauyu Baobab Ercolano, Barbar |
| contents | The radio emission mechanisms from accreting protoplanets, and their variability, link observations and physical properties. We revisit the variability of the ~343GHz (ALMA Band7) flux density from PDS70c (F_B7). The subtraction of the extended time-averaged signal may enable the measurement of the flux density from variable and embedded point sources. Visibility alignment and self-calibration yields close to thermal residuals in each execution block (EB) of ALMA observations, allowing the time-differential photometry of point-source in the visibility domain. The variability of PDS70c is checked against synthetic control point sources. In images of the 2017 ALMA dataset, with three ~1h EBs, PDS70c was detected only on 6 Dec. 2017, where F_B7 rose by 228%+-69% (3.3sigma). Time-differential photometry confirms a rise by 170%+-46% (3.7sigma). An application to ~2h EBs from the 2023 dataset resulted in constant flux densities, within a scatter of ~15%. However, F_B7(t) shows some scatter when splitting the deep 2023 EBs in 20min intervals, with a chi2 test significant at 2.6sigma, and an intrinsic dispersion of 49%21%. The radio variability of PDS70c, observed over hours but averaged out on longer timescales, is indeed expected if the signal is due to HI free-free from an accretion shock on a circum-planetary disk surface. A planet-to-environment mass ratio <1E-4 is required to avoid smoothing by radiative diffusion if the signal is due to thermal emission from the environment. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_24991 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Hourly radio variability of PDS70c from time-differential photometry Casassus, Simon Carcamo, Miguel Dominguez-Jamett, Oriana Aoyama, Yuhiko Marleau, Gabriel-Dominique Chrenko, Ondrej Liu, Hauyu Baobab Ercolano, Barbar Earth and Planetary Astrophysics The radio emission mechanisms from accreting protoplanets, and their variability, link observations and physical properties. We revisit the variability of the ~343GHz (ALMA Band7) flux density from PDS70c (F_B7). The subtraction of the extended time-averaged signal may enable the measurement of the flux density from variable and embedded point sources. Visibility alignment and self-calibration yields close to thermal residuals in each execution block (EB) of ALMA observations, allowing the time-differential photometry of point-source in the visibility domain. The variability of PDS70c is checked against synthetic control point sources. In images of the 2017 ALMA dataset, with three ~1h EBs, PDS70c was detected only on 6 Dec. 2017, where F_B7 rose by 228%+-69% (3.3sigma). Time-differential photometry confirms a rise by 170%+-46% (3.7sigma). An application to ~2h EBs from the 2023 dataset resulted in constant flux densities, within a scatter of ~15%. However, F_B7(t) shows some scatter when splitting the deep 2023 EBs in 20min intervals, with a chi2 test significant at 2.6sigma, and an intrinsic dispersion of 49%21%. The radio variability of PDS70c, observed over hours but averaged out on longer timescales, is indeed expected if the signal is due to HI free-free from an accretion shock on a circum-planetary disk surface. A planet-to-environment mass ratio <1E-4 is required to avoid smoothing by radiative diffusion if the signal is due to thermal emission from the environment. |
| title | Hourly radio variability of PDS70c from time-differential photometry |
| topic | Earth and Planetary Astrophysics |
| url | https://arxiv.org/abs/2604.24991 |