RECORD
UV variability and accretion dynamics in the young open cluster NGC 2264
Solar and Stellar Astrophysics · Submitted 23 Jun 2015
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim We conclude that for both accreting and non-accreting stars, the mid-term rotational modulation by spots is the leading timescale for a variability of up to several years.
The compiled record
The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
Open the compiled record
The abstract, sentence by sentence
We explore UV and optical variability signatures for several hundred members of NGC 2264 (3 Myr). We performed simultaneous u- and r-band monitoring over two full weeks with CFHT/MegaCam. About 750 young stars are probed; 40% of them are accreting. Statistically distinct variability properties are observed for accreting and non-accreting cluster members. The accretors exhibit a significantly higher level of variability than the non-accretors, especially in the UV. The amount of u-band variability correlates statistically with UV excess in disk-bearing objects, which suggests that accretion and star-disk interaction are the main sources of variability. Cool magnetic spots, several hundred degrees colder than the photosphere and covering from 5 to 30% of the stellar surface, appear to be the leading factor of variability for the non-accreting stars. In contrast, accretion spots, a few thousand degrees hotter than the photosphere and covering a few percent of the stellar surface, best reproduce the variability of accreting objects. The color behavior is also found to be different between accreting and non-accreting stars. Typical variability amplitudes for accreting members rapidly increase from r to u, which indicates a much stronger contrast at short wavelengths; a lower color dependence in the amplitudes is instead measured for diskless stars. We find that u-band variability on hour timescales is typically about 10% of the peak-to-peak variability on day timescales, while longer term (years) variability is consistent with amplitudes measured over weeks. We conclude that for both accreting and non-accreting stars, the mid-term rotational modulation by spots is the leading timescale for a variability of up to several years. In turn, this suggests that the accretion process is essentially stable over years, although it exhibits low-level shorter term variations in single accretion events.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We explore UV and optical variability signatures for several hundred members of NGC 2264 (3 Myr). | contribution 0.99 | 0.93 | 0.02 | asserted 0.80 |
| s1 | We performed simultaneous u- and r-band monitoring over two full weeks with CFHT/MegaCam. | method 1.00 | 0.97 | 0.01 | asserted 1.00 |
| s2 | About 750 young stars are probed; 40% of them are accreting. | result 0.60 | 0.92 | 0.02 | asserted 1.00 |
| s3 | Statistically distinct variability properties are observed for accreting and non-accreting cluster members. | result 1.00 | 0.92 | 0.16 | asserted 1.00 |
| s4 | The accretors exhibit a significantly higher level of variability than the non-accretors, especially in the UV. | result 1.00 | 0.93 | 0.22 | asserted 1.00 |
| s5 | The amount of u-band variability correlates statistically with UV excess in disk-bearing objects, which suggests that accretion and star-disk interaction are the main sources of variability. | interpretation 0.79 | 0.91 | 0.29 | hedged possibility 0.97 |
| s6 | Cool magnetic spots, several hundred degrees colder than the photosphere and covering from 5 to 30% of the stellar surface, appear to be the leading factor of variability for the non-accreting stars. | interpretation 0.61 | 0.85 | 0.07 | hedged possibility 0.93 |
| s7 | In contrast, accretion spots, a few thousand degrees hotter than the photosphere and covering a few percent of the stellar surface, best reproduce the variability of accreting objects. | interpretation 0.56 | 0.86 | 0.08 | hedged possibility 0.53 |
| s8 | The color behavior is also found to be different between accreting and non-accreting stars. | result 1.00 | 0.92 | 0.03 | asserted 1.00 |
| s9 | Typical variability amplitudes for accreting members rapidly increase from r to u, which indicates a much stronger contrast at short wavelengths; a lower color dependence in the amplitudes is instead measured for diskless stars. | result 0.98 | 0.95 | 0.06 | asserted 0.92 |
| s10 | We find that u-band variability on hour timescales is typically about 10% of the peak-to-peak variability on day timescales, while longer term (years) variability is consistent with amplitudes measured over weeks. | result 1.00 | 0.96 | 0.05 | asserted 0.98 |
| s11 | We conclude that for both accreting and non-accreting stars, the mid-term rotational modulation by spots is the leading timescale for a variability of up to several years. | result 0.58 | 0.92 | 0.54 | asserted 0.99 |
| s12 | In turn, this suggests that the accretion process is essentially stable over years, although it exhibits low-level shorter term variations in single accretion events. | interpretation 1.00 | 0.84 | 0.22 | hedged possibility 0.90 |
What was examined, and what was not
- arXiv listing abstract v1
- full text
- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
- S sections
- T body sentences
- C citations
- R cross-paper relations
The paper
Original abstract
We explore UV and optical variability signatures for several hundred members of NGC 2264 (3 Myr). We performed simultaneous u- and r-band monitoring over two full weeks with CFHT/MegaCam. About 750 young stars are probed; 40% of them are accreting. Statistically distinct variability properties are observed for accreting and non-accreting cluster members. The accretors exhibit a significantly higher level of variability than the non-accretors, especially in the UV. The amount of u-band variability correlates statistically with UV excess in disk-bearing objects, which suggests that accretion and star-disk interaction are the main sources of variability. Cool magnetic spots, several hundred degrees colder than the photosphere and covering from 5 to 30% of the stellar surface, appear to be the leading factor of variability for the non-accreting stars. In contrast, accretion spots, a few thousand degrees hotter than the photosphere and covering a few percent of the stellar surface, best reproduce the variability of accreting objects. The color behavior is also found to be different between accreting and non-accreting stars. Typical variability amplitudes for accreting members rapidly increase from r to u, which indicates a much stronger contrast at short wavelengths; a lower color dependence in the amplitudes is instead measured for diskless stars. We find that u-band variability on hour timescales is typically about 10% of the peak-to-peak variability on day timescales, while longer term (years) variability is consistent with amplitudes measured over weeks. We conclude that for both accreting and non-accreting stars, the mid-term rotational modulation by spots is the leading timescale for a variability of up to several years. In turn, this suggests that the accretion process is essentially stable over years, although it exhibits low-level shorter term variations in single accretion events.
Human review
Discussion
Know something about this paper? Leave a comment, or highlight any passage above to comment on it.