Time Variability of Emission Lines for Four Active T Tauri Stars. I. October–december in 2010

Chou, Mei Yin; Takami, M.; Manset, N.; Beck, Tracy; Pyo, Tae‐Soo; Chen, Wen-Ping; Panwar, Neelam; Karr, J.; Shang, Hsien; Liu, Hauyu Baobab

doi:10.1088/0004-6256/145/4/108

Cited by 32 publications

(52 citation statements)

References 92 publications

(194 reference statements)

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“…Since RW Aur A has been spectrally monitored at different wavelengths in the past decade, in particular in the optical (Alencar et al 2005;Chou et al 2013;Petrov et al 2015;Takami et al 2016) and in the UV (France et al 2012(France et al , 2014McJunkin et al 2013 The solid vertical lines show the dates when the UVES and X-shooter (black) spectra were taken (colour legend for UVES spectra is in Table 1). The dashed vertical lines show the dates of the four optical spectra by Chou et al (2013), which overlap on the used scale. The brown and grey dashed-dotted lines show the dates of the two UV HST spectra by France et al (2012France et al ( , 2014.…”

Section: Resultsmentioning

confidence: 99%

“…by Chou et al (2013). Interestingly, Chou et al (2013) obtained four different spectra during the ingress time of the first dimming event.…”

Section: Equivalent Widths and Column Densitiesmentioning

confidence: 96%

“…Interestingly, Chou et al (2013) obtained four different spectra during the ingress time of the first dimming event. It is apparent that there is a very fast transition from a line profile similar to those in the UVES spectra presented here, and a line profile that closely resembles our X-shooter profile.…”

Section: Equivalent Widths and Column Densitiesmentioning

confidence: 99%

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Violent environment of the inner disk of RW Aurigae A probed by the 2010 and 2015 dimming events

Facchini

Manara

Schneider

et al. 2016

A&A

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Aims. The young binary system RW Aur shows strong signatures of a recent tidal encounter between the circumprimary disk and the secondary star. The primary star has recently undergone two major dimming events (∆mag ≈ 2 in V band) whose origin is still under debate. To shed light on the mechanism leading to the dimming events, we study the extinction properties, accretion variability, and gas kinematics using absorption lines from the material that is obscuring RW Aur A. Methods. We compared our moderate-resolution X-shooter spectra of the dim state of RW Aur A with other spectral observations. In particular, we analysed archival high-resolution UVES spectra obtained during the bright state of the system to track the evolution of the spectral properties across the second dimming event. Since the X-shooter spectrum is flux calibrated, we provide new synthetic photometry of RW Aur A during the dim state. Results. The spectrum obtained during the dim state shows narrow absorption lines in the Na and K optical doublets, where the former is saturated. With a velocity of −60 km s −1 , these lines indicate that during the dim state the disk wind is either enhanced or significantly displaced into the line of sight. The photometric evolution across the dimming event shows a grey extinction, and is correlated with a significant reduction of the EW of all photospheric lines. Emission lines that trace accretion do not vary significantly across the dimming. Conclusions. From comparing our observations with complementary results from the last years, we conclude that the dimming event is related to a major perturbation on the inner disk. We suggest that the inner disk is occulting (most of) the star and thus its photosphere, but does not occult the accretion regions within a few stellar radii. Since observations of the outer disk indicate that the disk is modestly inclined (45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60) • ), we propose that the inner disk might be warped by an as yet unseen (sub-) stellar companion, which may also explain the 2.77 day periodic variability of the spectral lines.

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Section: Resultsmentioning

confidence: 99%

“…by Chou et al (2013). Interestingly, Chou et al (2013) obtained four different spectra during the ingress time of the first dimming event.…”

Section: Equivalent Widths and Column Densitiesmentioning

confidence: 96%

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Violent environment of the inner disk of RW Aurigae A probed by the 2010 and 2015 dimming events

Facchini

Manara

Schneider

et al. 2016

A&A

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“…The photometric variability is complemented by highly variable emission line profiles and veiling (e.g. Chou et al 2013;Costigan et al 2014) including in stars with relatively low accretion rates such as TW Hya and V2129 Oph (Alencar & Batalha 2002;Alencar et al 2012).…”

Section: Introductionmentioning

confidence: 99%

A Continuum of Accretion Burst Behavior in Young Stars Observed by K2

Cody

Hillenbrand

David

et al. 2017

ApJ

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We present 29 likely members of the young ρ Oph or Upper Sco regions of recent star formation that exhibit "accretion burst" type light curves in K2 time series photometry. The bursters were identified by visual examination of their ∼80 day light curves, though all satisfy the M < −0.25 flux asymmetry criterion for burst behavior defined by Cody et al. (2014). The burst sources represent ≈9% of cluster members with strong infrared excess indicative of circumstellar material. Higher amplitude burster behavior is correlated with larger inner disk infrared excesses, as inferred from WISE W 1 − W 2 color. The burst sources are also outliers in their large Hα emission equivalent widths. No distinction between bursters and non-bursters is seen in stellar properties such as multiplicity or spectral type. The frequency of bursters is similar between the younger, more compact ρ Oph region, and the older, more dispersed Upper Sco region. The bursts exhibit a range of shapes, amplitudes (∼10-700%), durations (∼1-10 days), repeat time scales (∼3-80 days), and duty cycles (∼10-100%). Our results provide important input to models of magnetospheric accretion, in particular by elucidating the properties of accretion-related variability in the low state between major longer duration events such as EX Lup and FU Ori type accretion outbursts. We demonstrate the broad continuum of accretion burst behavior in young stars -extending the phenomenon to lower amplitudes and shorter timescales than traditionally considered in the theory of pre-main sequence accretion history.

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“…They attributed this drop to an occultation by part of a tidally disrupted disk as evidenced in Cabrit et al (2006) and noted that such a long-lasting event had not been observed before. Chou et al (2013) collected high-resolution spectra during the beginning of the minimum indicating that no significant changes in the emission line spectrum had occurred. Normally, the star fluctuates in brightness by sometimes more than one magnitude in the V band and on time scales of a few days.…”

Section: Introductionmentioning

confidence: 99%

Another deep dimming of the classical T Tauri star RW Aurigae A

Петров¹,

Gahm²,

Djupvik³

et al. 2015

A&A

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Context. RW Aur A is a classical T Tauri star (CTTS) with an unusually rich emission line spectrum. In 2014 the star faded by ∼3 mag in the V band and went into a long-lasting minimum. In 2010 the star underwent a similar fading, although less pronounced. These events in RW Aur A are very unusual among the CTTS, and have been attributed to occultations by passing dust clouds. Aims. We want to find out if any spectral changes took place after the last fading of RW Aur A with the intention of gathering more information on the occulting body and the cause of the phenomenon. Methods. We collected spectra of the two components of RW Aur. The photometry was performed before and during the minimum. Results. The overall spectral signatures reflecting emission from accretion flows from disk to star did not change after the fading. However, blue-shifted absorption components related to the stellar wind increased in strength in certain resonance lines, and the profiles and strengths but not the fluxes of forbidden lines became drastically different. Conclusions. The extinction through the obscuring cloud is grey indicating the presence of large dust grains. At the same time, there are no traces of related absorbing gas. The cloud occults the star and the interior part of the stellar wind, but not the wind or jet further out. The dimming in 2014 was not accompanied by changes in the accretion flows at the stellar surface. There is evidence that the structure and velocity pattern of the stellar wind did change significantly. The dimmings could be related to passing condensations in a tidally disrupted disk, as proposed earlier, but we also speculate that large dust grains have been stirred up from the inclined disk into the line of sight through the interaction with an enhanced wind.

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Time Variability of Emission Lines for Four Active T Tauri Stars. I. October–december in 2010

Cited by 32 publications

References 92 publications

Violent environment of the inner disk of RW Aurigae A probed by the 2010 and 2015 dimming events

Violent environment of the inner disk of RW Aurigae A probed by the 2010 and 2015 dimming events

A Continuum of Accretion Burst Behavior in Young Stars Observed by K2

Another deep dimming of the classical T Tauri star RW Aurigae A

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