The Line Profile Variability of SU Aurigae

Johns, Christopher; Basri, Gibor

doi:10.1086/176059

Cited by 102 publications

(131 citation statements)

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“…They restore most of the Balmer line features seen in CTTSs, such as the lack of redshifted absorption in the Ha line compared to the higher Balmer lines and the slightly blueshifted emission peak of the Balmer lines. However, Johns & Basri (1995a) note that the nearly symmetric proÐle and the full width at zero level of the average Ha emission of SU Aur cannot be reproduced in an accretion funnel alone. Instead, they claim that the bulk Ha emission is produced in an almost stationary zone close to the star and that turbulence, not the velocity Ðeld, broadens the line.…”

Section: Introductionmentioning

confidence: 93%

“…A single snapshot, at any spectral resolution, allows, at the most, a short glance at an intricate gas Ñow. On the contrary, time series analysis allows for the search for correlations among selected components of line proÐles among several line groups and between line and continuum Ñuxes of a given star (Bertout et al 1982 ;Giampapa et al 1993 ;Johns & Basri 1995a, 1995bPetrov et al 1996 ;Johns-Krull & Basri 1997 ;Hessman & Guenther 1997 ;Lago & Gameiro 1998). SU Aur has been a common target for such analyses (Giampapa et al 1993 ;Johns & Basri 1995a ;Petrov et al 1996).…”

Section: Introductionmentioning

confidence: 99%

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Variability of Southern T Tauri Stars. I. The Continuum and the Hβ Inverse P Cygni Profile of GQ Lupi

Batalha¹,

Lopes²,

Batalha³

2001

Astrophysical Journal

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We present time series spectrophotometric observations of GQ Lupi, a typical representative of the YY Orionis subgroup of T Tauri stars that show conspicuous inverse P Cygni proÐles. The data set consists of 32 exposures taken over Ðve and eight consecutive nights of 1998 May and July, respectively, and covers the spectral range of 3100The region redward and next to the Balmer jump A \ j \ 5100 A . varies signiÐcantly on a night-to-night basis, and the amplitude of such variability decreases sharply at j [ 4600 The Balmer continuum slope indicates that the spectral energy distribution is governed by a A . gas of temperature greater than that of the stellar photosphere. The variability of the Balmer continuum Ñux has the largest amplitude. Flux increases in the B band are accompanied by concurrent Ñux increases in the U band. The contrary is not always veriÐed.The excess of continuum emission (veiling) for each exposure is computed throughout the spectral format. We Ðnd a tight anticorrelation between the veiling and the observed Balmer jump. We report the largest inverse P Cygni proÐle ever observed at this resolution : the depth of the Hb absorption component is nearly twice the height of the peak emission. Surprisingly, this absorption vanishes a few nights later. The time series of the redward absorption component behaves similarly to the veiling time series : the progressive weakening of the redward absorption is closely followed by a similar weakening of the excess continuum emission. If the absorption component is deveiled, the correlation strengthens. Thus, large/small redward absorption \ large/small veiling \ small/large Balmer jump.We model the emitting region by a gas of uniform temperature and density, each of the 32 exposures acting as a snapshot of such a region for a given stellar rotational phase. We explore models of temperature greater than 5000 K and number of hydrogen atoms larger than 1013 cm~3, extending the N H gas spectral energy distribution up to the blackbody of a given temperature. The resulting models indicate that the gas densities and the respective temperatures are strongly anticorrelated. In addition, the model time series show that the increase in the gas density is mirrored by an increase of the projected emitting area (Ðlling factor). Large/small gas densities and Ðlling factors are characterized by high/low observed veiling. As the accretion rate fades from night to night, the observed veiling decreases, as does the gas density and the total projected emitting area.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Variability of Southern T Tauri Stars. I. The Continuum and the Hβ Inverse P Cygni Profile of GQ Lupi

Batalha¹,

Lopes²,

Batalha³

2001

Astrophysical Journal

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“…The total residual on either side of the line centre was then determined. This tactic was intended primarily as a search for an anticorrelation between red shifted absorption and blue shifted emission, as reported by previous authors (Johns & Basri 1995;Oliveira et al 2000). Figure 5 shows correlation plots of the total red residual versus the total blue residual.…”

Section: Time Series Behaviourmentioning

confidence: 99%

“…Analysis of line profiles at high resolution for SU Aur was made by Johns & Basri (1995). They reported evidence of both infalling and outflowing components, which seemed to vary periodically with a 180 • phase difference.…”

Section: Introductionmentioning

confidence: 99%

Infall variability in the Classical T Tauri system VZ Chamaeleonis

Smith

Lewis

Bonnell

et al. 2001

A&A

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Abstract. We present time series spectroscopy of the Classical T Tauri star VZ Cha. We follow spectral variations at intermediate resolution over five successive nights, or approximately two rotation periods. We see profile features which persist on timescales longer than the expected infall time from the inner disc, and we see expected evidence of rotational variations in the lines, but we also note that rotation alone cannot produce all the observed variability and some other mechanism must be invoked. The behaviour of Hα is observed to be markedly different from that of the other lines. In particular, the evidence of rotational effects is lacking at Hα, and the activity in the red and blue wings of the line is not significantly correlated, in contrast to the other Balmer lines.

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“…Current models can account for the relatively slow rotation of most CTTSs (Camenzind 1990;Königl 1991;Shu et al 1994;Paatz & Camenzind 1996). Studies of the spectroscopic and photometric variability of CTTSs often suggest magnetically controlled accretion (e.g., Bertout, Basri, & Bouvier 1988;Herbst, BailerJones, & Mundt 2001;Alencar, Johns-Krull, & Basri 2001) with the magnetic axis inclined to the rotation axis in some cases (e.g., Kenyon et al 1994;Johns & Basri 1995;Bouvier et al 1999). Models of high-resolution Balmer line profiles, computed in the context of magnetospheric accretion, reproduce many aspects of observed line profiles (Muzerolle, , Muzerolle et al 2000.…”

Section: Introductionmentioning

confidence: 99%

New Tests of Magnetospheric Accretion in T Tauri Stars

Johns–Krull

Gafford

2002

ApJ

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We examine three analytic theories of magnetospheric accretion onto classical T Tauri stars (CTTSs) under the assumption that the magnetic field strength does not vary appreciably from star to star. From these investigations we derive predicted relationships among the stellar mass, radius, rotation period, and disk accretion rate. Data from five studies of the accretion parameters of CTTSs are used to test the predicted correlations. We generally find that the data do not display the predicted correlations except for that predicted by the model of Shu et al. as detailed by Ostriker & Shu and extended here to include nondipole field topologies. Their identification of the trapped flux as an important quantity in the model appears to be critical for reconciling the observed data to the theory. While the data do generally support the extended Ostriker & Shu predictions, only one of the two studies for which the requisite data exist shows the highest correlation when considering all the relevant parameters. This suggests that great care must be taken when trying to use existing observations to test the theory.

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The Line Profile Variability of SU Aurigae

Cited by 102 publications

References 0 publications

Variability of Southern T Tauri Stars. I. The Continuum and the Hβ Inverse P Cygni Profile of GQ Lupi

Variability of Southern T Tauri Stars. I. The Continuum and the Hβ Inverse P Cygni Profile of GQ Lupi

Infall variability in the Classical T Tauri system VZ Chamaeleonis

New Tests of Magnetospheric Accretion in T Tauri Stars

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