Rotation and accretion of very low mass objects in the SigmaOri cluster
| dc.creator | Scholz, Alexander | |
| dc.creator | Eisloeffel, Jochen | |
| dc.date | 2004-04-01 | |
| dc.date.accessioned | 2026-07-07T02:12:47Z | |
| dc.date.available | 2026-07-07T02:12:47Z | |
| dc.description | We report on two photometric monitoring campaigns of Very Low Mass (VLM) objects in the young open cluster around SigmaOrionis. Our targets were pre-selected with multi-filter photometry in a field of 0.36 sqdeg. For 23 of these objects, spanning a mass range from 0.03 to 0.7 MS, we detect periodic variability. Of these, 16 exhibit low-level variability, with amplitudes of less than 0.2 mag in the I-band, which is mostly well-approximated by a sine wave. These periodicities are probably caused by photospheric spots co-rotating with the objects. In contrast, the remaining variable targets show high-level variability with amplitudes ranging from 0.25 to 1.1 mag, consisting of a periodic light variation onto which short-term fluctuations are superimposed. This variability pattern is very similar to the photometric behaviour of solar-mass, classical T Tauri stars. Low-resolution spectra of a few of these objects reveal strong Halpha and Ca-triplet emission, indicative of ongoing accretion processes. This suggests that 5-7% of our targets still possess a circumstellar disk. In combination with previous results for younger objects, this translates into a disk lifetime of 3-4 Myr, significantly shorter than for solar mass stars. The highly variable objects rotate on average slower than the low-amplitude variables, which is expected in terms of a disk-locking scenario. There is a trend towards faster rotation with decreasing mass, which might be caused by shortening of the disk lifetimes or attenuation of magnetic fields. | |
| dc.description | 19 pages, 14 figures, A&A, in press | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0404014 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0404014 | |
| dc.identifier | Astron.Astrophys. 419 (2004) 249-267 | |
| dc.identifier | doi:10.1051/0004-6361:20034022 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/7576 | |
| dc.subject | Astrophysics | |
| dc.title | Rotation and accretion of very low mass objects in the SigmaOri cluster | |
| dc.type | text |