Saved in:
| Main Authors: | , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2502.08842 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866910858569842688 |
|---|---|
| author | Percy, John Szpigiel, Melanie |
| author_facet | Percy, John Szpigiel, Melanie |
| contents | At least a third of red giants show a long secondary period (LSP), 5 to 10 times longer than the pulsation period. There is strong evidence that the LSP is caused by eclipses of the red giant by a dust-enshrouded low-mass companion. We have used long-term AAVSO observations of 11 stars to study two aspects of the eclipse hypothesis: the relation between the LSP phase (eclipse) curve and the geometry of the eclipse, and the long-term (decades) changes in the LSP phenomenon in each star. The stars with the largest LSP amplitudes show evidence of a dust tail on the companion, but most of the 11 stars show only a small-amplitude sinusoidal phase curve. The LSP amplitudes of all the stars vary slowly by up to a factor of 8, suggesting that the amount of obscuring dust varies by that amount, but there is no strong evidence that the geometry of the system changes over many decades. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2502_08842 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Long Secondary Periods in Red Giants: AAVSO Observations and the Eclipse Hypothesis Percy, John Szpigiel, Melanie Solar and Stellar Astrophysics At least a third of red giants show a long secondary period (LSP), 5 to 10 times longer than the pulsation period. There is strong evidence that the LSP is caused by eclipses of the red giant by a dust-enshrouded low-mass companion. We have used long-term AAVSO observations of 11 stars to study two aspects of the eclipse hypothesis: the relation between the LSP phase (eclipse) curve and the geometry of the eclipse, and the long-term (decades) changes in the LSP phenomenon in each star. The stars with the largest LSP amplitudes show evidence of a dust tail on the companion, but most of the 11 stars show only a small-amplitude sinusoidal phase curve. The LSP amplitudes of all the stars vary slowly by up to a factor of 8, suggesting that the amount of obscuring dust varies by that amount, but there is no strong evidence that the geometry of the system changes over many decades. |
| title | Long Secondary Periods in Red Giants: AAVSO Observations and the Eclipse Hypothesis |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2502.08842 |