Mon. Not. R. Astron. Soc., 486, 4590-4611 (2019/July-2)
Determining the recurrence time-scale of long-lasting YSO outbursts.
CONTRERAS PENA C., NAYLOR T. and MORRELL S.
Abstract (from CDS):
We have determined the rate of large accretion events in Class I and II young stellar objects (YSOs) by comparing the all-sky digitized photographic plate surveys provided by SuperCOSMOS with the latest data release from Gaia (DR2). The long mean baseline of 55 yr along with a large sample of Class II YSOs (≃15 000) allows us to study approximately 1 million YSO-years. We find 139 objects with ΔR >= 1 mag, most of which are found at amplitudes between 1 and 3 mag. The majority of YSOs in this group show irregular variability or long-lasting fading events, which is best explained as hotspots due to accretion or by variable extinction. There is a tail of YSOs at ΔR >= 3 mag and they seem to represent a different population. Surprisingly many objects in this group show high-amplitude irregular variability over time-scales shorter than 10 yr, in contrast with the view that high-amplitude objects always have long outbursts. However, we find six objects that are consistent with undergoing large, long-lasting accretion events, three of them previously unknown. This yields an outburst recurrence time-scale of 112 kyr, with a 68 per cent confidence interval [74-180] kyr. This represents the first robust determination of the outburst rate in Class II YSOs and shows that YSOs in their planet-forming stage do in fact undergo large accretion events, and with time-scales of ≃100 000 yr. In addition, we find that outbursts in the Class II stage are ≃10 times less frequent than during the Class I stage.
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
stars: formation - stars: pre-main-sequence - stars: protostars - stars: variables: T Tauri, Herbig Ae/Be
VizieR on-line data:
<Available at CDS (J/MNRAS/486/4590): table2.dat table1.dat>
View the references in ADS
To bookmark this query, right click on this link: simbad:2019MNRAS.486.4590C and select 'bookmark this link' or equivalent in the popup menu