Csi 2264: Characterizing Accretion-Burst Dominated Light Curves for Young Stars in NGC 2264

Stauffer, J. R.; Cody, Ann Marie; Baglin, A.; Alencar, S. H. P.; Rebull, L. M.; Hillenbrand, Lynne A.; Venuti, L.; Turner, Neal J.; Carpenter, John M.; Plavchan, Peter; Findeisen, K.; Carey, Sean; Terebey, S.; Morales-Calderón, M.; Bouvier, J.; Micela, G.; Flaccomio, E.; Song, Inseok; Gutermuth, R. A.; Hartmann, L.; Calvet, Nuria; Whitney, B. A.; Barrado, D.; Vrba, F. J.; Covey, Kevin R.; Herbst, W.; Fürész, Gábor; Aigrain, S.; Favata, F.

doi:10.1088/0004-6256/147/4/83

Cited by 129 publications

(191 citation statements)

References 53 publications

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“…This paper, and the others in this series Cody et al 2014;Stauffer et al 2014;McGinnis et al 2015) demonstrate how high cadence, long duration, sensitive, photometrically stable light curves can be used to infer physical properties of YSOs that are otherwise impossible to investigate. In this paper, we have identified a new YSO light curve class characterized by short-duration, shallow, periodic flux dips.…”

Section: Discussionmentioning

confidence: 59%

“…First results from our 2011-2012 intensive monitoring of NGC 2264 with CoRoT and Spitzer have been published in Cody et al (2014) and Stauffer et al (2014). While working on those papers, we noticed a small set of stars that shared some similarities but did not seem to fit into the primary groupings identified by Cody et al (2014).…”

Section: Identification and Initial Characterization Of Ysos With Shomentioning

confidence: 87%

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Csi 2264: Characterizing Young Stars in NGC 2264 With Short-Duration Periodic Flux Dips in Their Light Curves

Stauffer

Cody

McGinnis

et al. 2015

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We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical CoRoT light curves exhibiting short-duration, shallow periodic flux dips. All of these stars have infrared excesses that are consistent with their having inner disk walls near the Keplerian co-rotation radius. The repeating photometric dips have FWHMs generally less than 1 day, depths almost always less than 15%, and periods (3 < P < 11 days) consistent with dust near the Keplerian co-rotation period. The flux dips vary considerably in their depth from epoch to epoch, but usually persist for several weeks and, in two cases, were present in data collected in successive years. For several of these stars, we also measure the photospheric rotation period and find that the rotation and dip periods are the same, as predicted by standard "disk-locking" models. We attribute these flux dips to clumps of material in or near the inner disk wall, passing through our line of sight to the stellar photosphere. In some cases, these dips are also present in simultaneous Spitzer IRAC light curves at 3.6 and 4.5 microns. We characterize the properties of these dips, and compare the stars with light curves exhibiting this behavior to other classes of YSOs in NGC 2264. A number of physical mechanisms could locally increase the dust scale height near the inner disk wall, and we discuss several of those mechanisms; the most plausible mechanisms are either a disk warp due to interaction with the stellar magnetic field or dust entrained in funnel-flow accretion columns arising near the inner disk wall.

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Section: Discussionmentioning

confidence: 59%

Section: Identification and Initial Characterization Of Ysos With Shomentioning

confidence: 87%

Csi 2264: Characterizing Young Stars in NGC 2264 With Short-Duration Periodic Flux Dips in Their Light Curves

Stauffer

Cody

McGinnis

et al. 2015

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“…If the spectral lines are veiled by accretion activities, l W 6708 (Li) may (Calvet & Gullbring 1998), and the lifetime of hot spots created by the accreted materials may also be different for a different accretion rate. The intensive time series observations of some PMS stars in NGC 2264 show aperiodic or periodic brightening events in their light curves on a timescale of several hours to 30 days (Stauffer et al 2014(Stauffer et al , 2016. The aperiodic events are related to the variable mass accretion rate, and the rotational modulation of long-lived hot spots is responsible for the periodic light curves.…”

Section: The Effect Of Veiling On the LI L6708 Linementioning

confidence: 99%

A Constraint on the Formation Timescale of the Young Open Cluster NGC 2264: Lithium Abundance of Pre-Main Sequence Stars

Lim

Sung

Kim

et al. 2016

ApJ

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The timescale of cluster formation is an essential parameter in order to understand the formation process of star clusters. Pre-main sequence (PMS) stars in nearby young open clusters reveal a large spread in brightness. If the spread were considered to be a result of a real spread in age, the corresponding cluster formation timescale would be about 5-20 Myr. Hence it could be interpreted that star formation in an open cluster is prolonged for up to a few tens of Myr. However, difficulties in reddening correction, observational errors, and systematic uncertainties introduced by imperfect evolutionary models for PMS stars can result in an artificial age spread. Alternatively, we can utilize Li abundance as a relative age indicator of PMS star to determine the cluster formation timescale. The optical spectra of 134 PMS stars in NGC 2264 have been obtained with MMT/Hectochelle. The equivalent widths have been measured for 86 PMS stars with a detectable Li line (). Li abundance under the condition of local thermodynamic equilibrium (LTE) was derived using the conventional curve of growth method. After correction for non-LTE effects, we find that the initial Li abundance of NGC 2264 is. From the distribution of the Li abundances, the underlying age spread of the visible PMS stars is estimated to be about 3-4 Myr and this, together with the presence of embedded populations in NGC 2264, suggests that the cluster formed on a timescale shorter than 5 Myr.

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“…Accretion variability is common in young stellar objects, as 10% of CTTSs have similar bursty light curves (Findeisen et al 2013;Cody et al 2014Cody et al , 2017Stauffer et al 2014). The variable accretion process appears as changes in excess continuum and line emission above the photosphere (e.g., Alencar et al 2012;Fang et al 2013;Costigan et al 2014), and the corresponding changes in photometry (Venuti et al 2014;Sousa et al 2016;Stauffer et al 2016;Tofflemire et al 2017a) are driven by either unsteady star-disk connections (e.g., Romanova et al 2013) or changes in the disk density at the inner rim (Robinson et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Guo

Herczeg

Jose

et al. 2018

ApJ

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The variability of young stellar objects is mostly driven by star-disk interactions. In long-term photometric monitoring of the accreting T Tauri star GI Tau, we detect extinction events with typical depths of DṼ 2.5 mag that last for days to months and often appear to occur stochastically. In 2014-2015, extinctions that repeated with a quasi-period of 21 days over several months are the first empirical evidence of slow warps predicted by magnetohydrodynamic simulations to form at a few stellar radii away from the central star. The reddening is consistent with =  R 3.85 0.5 V and, along with an absence of diffuse interstellar bands, indicates that some dust processing has occurred in the disk. The 2015-2016 multiband light curve includes variations in spot coverage, extinction, and accretion, each of which results in different traces in color-magnitude diagrams. This light curve is initially dominated by a month-long extinction event and a return to the unocculted brightness. The subsequent light curve then features spot modulation with a 7.03 day period, punctuated by brief, randomly spaced extinction events. The accretion rate measured from U-band photometry ranges from´-1.3 10 8 to´-1.1 10 10 M e yr −1 (excluding the highest and lowest 5% of high-and low-accretion rate outliers), with an average of4.7 -10 9 M e yr −1 . A total of 50% of the mass is accreted during bursts of >´-12.8 10 9 M e yr -1, which indicates limitations on analyses of disk evolution using single-epoch accretion rates.

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Csi 2264: Characterizing Accretion-Burst Dominated Light Curves for Young Stars in NGC 2264

Cited by 129 publications

References 53 publications

Csi 2264: Characterizing Young Stars in NGC 2264 With Short-Duration Periodic Flux Dips in Their Light Curves

Csi 2264: Characterizing Young Stars in NGC 2264 With Short-Duration Periodic Flux Dips in Their Light Curves

A Constraint on the Formation Timescale of the Young Open Cluster NGC 2264: Lithium Abundance of Pre-Main Sequence Stars

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

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