Mid?Infrared Observations of T Tauri Stars: Probing the Star?Disk Connection in Rotational Evolution

Kundurthy, P.; Meyer, Michael; Robberto, M.; Beckwith, S.; Herbst, Tom

doi:10.1086/508607

Cited by 16 publications

(12 citation statements)

References 63 publications

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“…This indicates that a very efficient mechanism is at work to remove the angular momentum in these stars; the nature of this mechanism is still controversial. Kundurthy et al (2006), see also Edwards et al (1993), claimed that CTTS are slow rotators with circumstellar disks, while WTTS are fast rotators without accretion disks. However, the association of CTTS with slow rotators and WTTS with fast ones is not as yet observationally confirmed.…”

Section: The Angular Momentum Problem Observational Factsmentioning

confidence: 98%

Nonradial and nonpolytropic astrophysical outflows

Sauty

Méliani

Lima

et al. 2011

A&A

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Context. A large sample of T Tauri stars exhibits optical jets, approximately half of which rotate slowly, only at ten per cent of their breakup velocity. The disk-locking mechanism has been shown to be inefficient to explain this observational fact. Aims. We show that low mass accreting T Tauri stars may have a strong stellar jet component that can effectively brake the star to the observed rotation speed. Methods. By means of a nonlinear separation of the variables in the full set of the MHD equations we construct semi-analytical solutions describing the dynamics and topology of the stellar component of the jet that emerges from the corona of the star. Results. We analyze two typical solutions with the same mass loss rate but different magnetic lever arms and jet radii. The first solution with a long lever arm and a wide jet radius effectively brakes the star and can be applied to the visible jets of T Tauri stars such as RY Tau. The second solution with a shorter lever arm and a very narrow jet radius may explain why similar stars, either weak line T Tauri stars (WTTS) or classical T Tauri stars (CTTS) do not all have visible jets. For instance, RY Tau itself seems to have different phases that probably depend on the activity of the star. Conclusions. First, stellar jets seem to be able to brake pre-main sequence stars with a low mass accreting rate. Second, jets may be visible only part time owing to changes in their boundary conditions. We also suggest a possible scenario for explaining the dichotomy between CTTS and WTTS, which rotate faster and do not have visible jets.

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Section: The Angular Momentum Problem Observational Factsmentioning

confidence: 98%

Nonradial and nonpolytropic astrophysical outflows

Sauty

Méliani

Lima

et al. 2011

A&A

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“…(Continued) where N is the number of measurements, μ i are the reported magnitudes, and σ At longer infrared wavelengths, the SEDs shown in Figure 13(a) were collected primarily from Spitzer imaging surveys (Luhman et al 2010;Rebull et al 2010), the Wide-field Infrared Survey Explorer all-sky catalog (Wright et al 2010), the AKARI point source catalogs (Ishihara et al 2010), and the Infrared Astronomical Satellite (IRAS) point source catalog (Beichman et al 1988), with some additional ground-and space-based measurements (Strom et al 1989;Hillenbrand et al 1992;Malfait et al 1998 Metchev et al 2004;Pantin et al 2005;McCabe et al 2006McCabe et al , 2011Kundurthy et al 2006;Mariñas et al 2006;Bouy et al 2008;Monnier et al 2008;Ratzka et al 2009;Duchêne et al 2010;Honda et al 2010;Skemer et al 2010;Wahhaj et al 2010;Gräfe et al 2011;Harvey et al 2012). In addition to the new data presented here (see Table 1), integrated flux density measurements in the submillimeter-radio spectrum are compiled from various catalogs in the literature (Weintraub et al 1989;Adams et al 1990;Beckwith et al 1990;Beckwith & Sargent 1991;Altenhoff et al 1994;Jewitt 1994;Mannings & Emerson 1994;Jensen et al 1994;Koerner et al 1995;Osterloh & Beckwith 1995;…”

Section: Appendix a Spectral Energy Distributionsmentioning

confidence: 99%

The Mass Dependence Between Protoplanetary Disks and Their Stellar Hosts

Andrews

Rosenfeld

Kraus

et al. 2013

ApJ

662

1,029

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We present a substantial extension of the millimeter (mm) wave continuum photometry catalog for circumstellar dust disks in the Taurus star-forming region, based on a new "snapshot" λ = 1.3 mm survey with the Submillimeter Array. Combining these new data with measurements in the literature, we construct a mm-wave luminosity distribution, f (L mm ), for Class II disks that is statistically complete for stellar hosts with spectral types earlier than M8.5 and has a 3σ depth of roughly 3 mJy. The resulting census eliminates a longstanding selection bias against disks with late-type hosts, and thereby demonstrates that there is a strong correlation between L mm and the host spectral type. By translating the locations of individual stars in the Hertzsprung-Russell diagram into masses and ages, and adopting a simple conversion between L mm and the disk mass, M d , we confirm that this correlation corresponds to a statistically robust relationship between the masses of dust disks and the stars that host them. A Bayesian regression technique is used to characterize these relationships in the presence of measurement errors, data censoring, and significant intrinsic scatter: the best-fit results indicate a typical 1.3 mm flux density of ∼25 mJy for 1 M hosts and a power-law scaling L mm ∝ M 1.5−2.0 * . We suggest that a reasonable treatment of dust temperature in the conversion from L mm to M d favors an inherently linear M d ∝ M * scaling, with a typical disk-to-star mass ratio of ∼0.2%-0.6%. The measured rms dispersion around this regression curve is ±0.7 dex, suggesting that the combined effects of diverse evolutionary states, dust opacities, and temperatures in these disks imprint a full width at half-maximum range of a factor of ∼40 on the inferred M d (or L mm ) at any given host mass. We argue that this relationship between M d and M * likely represents the origin of the inferred correlation between giant planet frequency and host star mass in the exoplanet population, and provides some basic support for the core accretion model for planet formation. Moreover, we caution that the effects of incompleteness and selection bias must be considered in comparative studies of disk evolution, and illustrate that fact with statistical comparisons of f (L mm ) between the Taurus catalog presented here and incomplete subsamples in the Ophiuchus, IC 348, and Upper Sco young clusters.

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“…It has been suggested that during the pre-main-sequence phase of evolution, rotation is likely regulated by magnetic coupling to a circumstellar disk (e.g., Edwards et al 1993;Kundurthy et al 2006), although this mechanism is still a matter of debate (e.g., Stassun et al 1999;Nguyen et al 2009). Once the disk dissipates in ∼1-10 Myr , a star or VLM object will speed up due to its continued contraction.…”

Section: Intrinsic Rotational Velocity Differences?mentioning

confidence: 99%

Rotational Velocities of Individual Components in Very Low Mass Binaries

Konopacky

Ghez

Fabrycky

et al. 2012

ApJ

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We present rotational velocities for individual components of 11 very low mass (VLM) binaries with spectral types between M7 and L7.5. These results are based on observations taken with the near-infrared spectrograph, NIRSPEC, and the Keck II laser guide star adaptive optics system. We find that the observed sources tend to be rapid rotators (v sin i > 10 km s −1 ), consistent with previous seeing-limited measurements of VLM objects. The two sources with the largest v sin i, LP 349−25B and HD 130948C, are rotating at ∼30% of their break-up speed, and are among the most rapidly rotating VLM objects known. Furthermore, five binary systems, all with orbital semimajor axes 3.5 AU, have component v sin i values that differ by greater than 3σ . To bring the binary components with discrepant rotational velocities into agreement would require the rotational axes to be inclined with respect to each other, and that at least one component is inclined with respect to the orbital plane. Alternatively, each component could be rotating at a different rate, even though they have similar spectral types. Both differing rotational velocities and inclinations have implications for binary star formation and evolution. We also investigate possible dynamical evolution in the triple system HD 130948A−BC. The close binary brown dwarfs B and C have significantly different v sin i values. We demonstrate that components B and C could have been torqued into misalignment by the primary star, A, via orbital precession. Such a scenario can also be applied to another triple system in our sample, GJ 569A−Bab. Interactions such as these may play an important role in the dynamical evolution of VLM binaries. Finally, we note that two of the binaries with large differences in component v sin i, LP 349−25AB and 2MASS 0746+20AB, are also known radio sources.

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Mid?Infrared Observations of T Tauri Stars: Probing the Star?Disk Connection in Rotational Evolution

Cited by 16 publications

References 63 publications

Nonradial and nonpolytropic astrophysical outflows

Nonradial and nonpolytropic astrophysical outflows

The Mass Dependence Between Protoplanetary Disks and Their Stellar Hosts

Rotational Velocities of Individual Components in Very Low Mass Binaries

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