The many-faceted light curves of young disk-bearing stars in Upper Sco and $ρ$ Oph observed by $K2$ Campaign 2

Ann Marie Cody; Lynne A. Hillenbrand

doi:10.3847/1538-3881/aacead

paper

The many-faceted light curves of young disk-bearing stars in Upper Sco and $ρ$ Oph observed by $K 2$ Campaign 2

arXiv:1802.06409 · doi:10.3847/1538-3881/aacead

Abstract

The $K 2$ Mission has photometrically monitored thousands of stars at high precision and cadence in a series of $\sim$ 80-day campaigns focused on sections of the ecliptic plane. During its second campaign, $K 2$ targeted over 1000 young stellar objects (YSOs) in the $\sim$ 1-3 Myr $ρ$ Ophiuchus and 5-10 Myr Upper Scorpius regions. From this set, we have carefully vetted photometry from {\em WISE} and {\em Spitzer} to identify those YSOs with infrared excess indicative of primordial circumstellar disks. We present here the resulting comprehensive sample of 288 young disk-bearing stars from B through M spectral types and analysis of their associated $K 2$ light curves. Using statistics of periodicity and symmetry, we categorize each light curves into eight different variability classes, notably including "dippers" (fading events), "bursters" (brightening events), stochastic, and quasi-periodic types. Nearly all (96\%) of disk-bearing YSOs are identified as variable at 30-minute cadence with the sub-1\% precision of {\em K2}. Combining our variability classifications with (circum)stellar properties, we find that the bursters, stochastic sources, and the largest amplitude quasi-periodic stars have larger infrared colors, and hence stronger circumstellar disks. They also tend to have larger H $α$ equivalent widths, indicative of higher accretion rates. The dippers, on the other hand, cluster toward moderate infrared colors and low H $α$ . Using resolved disk observations, we further find that the latter favor high inclinations, apart from a few notable exceptions with close to face-on disks. These observations support the idea that YSO time domain properties are dependent on several factors including accretion rate and view angle.

Revised version: AJ in press. 54 pages (29 of which are light curves), 3 tables, 14 figures

The many-faceted light curves of young disk-bearing stars in Upper Sco and $ρ$ Oph observed by $K 2$ Campaign 2

Abstract

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Cited by in corpus (73)

The many-faceted light curves of young disk-bearing stars in Upper Sco and ρ Oph observed by K2 Campaign 2

Abstract

References in corpus (25)

Cited by in corpus (73)

The many-faceted light curves of young disk-bearing stars in Upper Sco and $ρ$ Oph observed by $K 2$ Campaign 2