Probable Association of T Tauri Stars with the L 1014 Dense Core

Akimichi, Morita; Watanabe, Makoto; Sugitani, Koji; Itoh, Yoichi; Uehara, Mari; Nagashima, Chie; Ebizuka, Noboru; Hasegawa, Takashi; Kinugasa, K.; Tamura, Motohide

doi:10.1093/pasj/58.5.l41

Cited by 6 publications

(7 citation statements)

References 24 publications

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“…Young et al (2004) assumed a distance of 200 pc but noted the true distance was only strongly constrained to be less than 1 kpc based on a lack of foreground stars. Morita et al (2006) argued for a larger distance of 400−900 pc based on comparing the positions of three nearby T Tauri stars in color-magnitude space with stellar evolutionary models, although it is unclear if these three sources are truly associated with L1014, and if their results would change by comparing to stellar evolutionary models that include the effects of the early accretion history (e.g., Baraffe et al 2009;Hosokawa et al 2011;Baraffe et al 2012). Maheswar et al (2011) derived a distance of 258 ± 50 pc based on an analysis of A V vs. distance for stars detected by 2MASS, and we adopt this distance in this study.…”

Section: L1014mentioning

confidence: 99%

Molecular Outflows Driven by Low-Mass Protostars. I. Correcting for Underestimates When Measuring Outflow Masses and Dynamical Properties

Dunham

Arce

Mardones

et al. 2014

ApJ

118

183

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We present a survey of 28 molecular outflows driven by low-mass protostars, all of which are sufficiently isolated spatially and/or kinematically to fully separate into individual outflows. Using a combination of new and archival data from several single-dish telescopes, 17 outflows are mapped in 12 CO (2-1) and 17 are mapped in 12 CO (3-2), with 6 mapped in both transitions. For each outflow, we calculate and tabulate the mass (M flow ), momentum (P flow ), kinetic energy (E flow ), mechanical luminosity (L flow ), and force (F flow ) assuming optically thin emission in LTE at an excitation temperature, T ex , of 50 K. We show that all of the calculated properties are underestimated when calculated under these assumptions. Taken together, the effects of opacity, outflow emission at low velocities confused with ambient cloud emission, and emission below the sensitivities of the observations increase outflow masses and dynamical properties by an order of magnitude, on average, and factors of 50-90 in the most extreme cases. Different (and non-uniform) excitation temperatures, inclination effects, and dissociation of molecular gas will all work to further increase outflow properties. Molecular outflows are thus almost certainly more massive and energetic than commonly reported. Additionally, outflow properties are lower, on average, by almost an order of magnitude when calculated from the 12 CO (3-2) maps compared to the 12 CO (2-1) maps, even after accounting for different opacities, map sensitivities, and possible excitation temperature variations. It has recently been argued in the literature that the 12 CO (3-2) line is subthermally excited in outflows, and our results support this finding. Data ReductionLow-order polynomial baselines were subtracted from all of the raw data using the default software package for each telescope: Continuum and Line Analysis Singledish Software (CLASS 11 ) for APEX, CSO, SRAO, and SMT, NEWSTAR 12 for ASTE, and Starlink 13 for the JCMT. These packages were then used to combine together all observations of a particular source and write out FITS datacubes on grids of Nyquist sampled spatial pixels. Further analysis was performed using custom IDL procedures. RESULTS

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Section: L1014mentioning

confidence: 99%

Molecular Outflows Driven by Low-Mass Protostars. I. Correcting for Underestimates When Measuring Outflow Masses and Dynamical Properties

Dunham

Arce

Mardones

et al. 2014

ApJ

118

183

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“…For the previously published papers from the Cores to Disk Legacy group, a distance of 200 pc was assumed. Recent observation of T-Tauri stars, presumed to be associated with the L1014 dense core, indicate that the distance is greater than 400 pc and may be as large as 900 pc (Morita et al 2006). The association of the T Tauri stars with the dense core is not clear as L1014 is located in a region with multiple dark clouds within a few degrees.…”

Section: Water Maser Non-detectionsmentioning

confidence: 99%

“…This object has been classified as a VeLLO (Very Low-Luminosity Object) by the c2d team: an object with an internal protostellar luminosity ≤ 0.1L ⊙ that is directly associated with a dense molecular core. The recent study of Morita et al (2006) has suggested a revised distance estimate of 400 to 900 pc based on the possible age ranges of nearby T-Tauri stars that are spatially within 2 • of the L1014 dense core. However, it is not clear that these T-Tauri stars are directly associated with L1014.…”

Section: Introductionmentioning

confidence: 99%

The Detection and Characterization of Centimeter Radio Continuum Emission from the Low‐Mass Protostar L1014‐IRS

Shirley

Claussen²,

Bourke

et al. 2007

ApJ

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Observations by the Cores to Disk Legacy Team with the Spitzer Space Telescope have identified a low luminosity, mid-infrared source within the dense core, Lynds 1014, which was previously thought to harbor no internal source. Followup near-infrared and submillimeter interferometric observations have confirmed the protostellar nature of this source by detecting scattered light from an outflow cavity and a weak molecular outflow. In this paper, we report the detection of cm continuum emission with the VLA. The emission is characterized by a quiescent, unresolved 90 µJy 6 cm source within 0. ′′ 2 of the Spitzer source. The spectral index of the quiescent component is α = 0.37 ± 0.34 between 6 cm and 3.6 cm. A factor of two increase in 6 cm emission was detected during one epoch and circular polarization was marginally detected at the 5σ level with Stokes V/I = 48 ± 16% . We have searched for 22 GHz H 2 O maser emission toward L1014-IRS, but no masers were detected during 7 epochs of observations between June 2004 and December 2006. L1014-IRS appears to be a low-mass, accreting protostar which exhibits cm emission from a thermal jet or a wind, with a variable nonthermal emission component. The quiescent cm radio emission is noticeably above the correlation of 3.6 cm and 6 cm luminosity versus bolometric luminosity, indicating more radio emission than expected. In this paper, we characterize the cm continuum emission in terms of observations of other low-mass protostars, including updated correlations of centimeter continuum emission with bolometric luminosity and outflow force, and discuss the implications of recent larger distance estimates on the physical attributes of the protostar and dense molecular core.

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“…Ho et al (1978) adopted a distance of 200 pc for B362. Morita et al (2006) assigned a distance of 400-900 pc to L1014 by assuming that this cloud is associated with identified T Tauri stars with the cloud. No reliable estimate of distance to L1014-2 is available in the literature.…”

Section: L1014mentioning

confidence: 99%

“…For example, the authors who carried out studies on the VeLLO in L1014 have assumed a distance of 200 pc to the cloud . But recently, Morita et al (2006) have quoted a distance of 400-900 pc for L1014. Then the VeLLO, with luminosity of L ∼ 0.09L ⊙ (calculated using the assumed distance of 200 pc to the cloud), becomes 0.36−1.8L ⊙ and ceases to be a VeLLO.…”

Section: Introductionmentioning

confidence: 99%

Distances to dense cores that contain very low luminosity objects

Maheswar

Lee

Dib

2011

A&A

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Aims. We estimate the distances to dense molecular cores that harbour very low luminosity objects (VeLLOs) detected by the Spitzer Space Telescope and attempt to confirm their VeLLO nature. Methods. The cloud distances are estimated using a near-IR photometric method. We use a technique that performs a spectral classification of stars lying towards the fields containing the clouds as either main-sequence stars or giants. In this technique, the observed (J − H) and (H − K s ) colours are dereddened simultaneously using trial values of A V and a normal interstellar extinction law. The best fit of the dereddened colours to the intrinsic colours giving a minimum value of χ 2 then yields the corresponding spectral type and A V for the star. The main-sequence stars, thus classified, are then utilized in an A V versus distance plot to bracket the cloud distances. The typical error in the estimation of distances to the clouds are found to be ∼18%. Results. We estimate distances to seven cloud cores, IRAM 04191, L1521F, BHR 111, L328, L673-7, L1014, and L1148 using the above method. These clouds contain VeLLO candidates. The estimated distances to the cores are found to be 127 ± 25 pc (IRAM 04191), 136 ± 36 pc (L1521F), 355 ± 65 pc (BHR 111), 217 ± 30 pc (L328), 240 ± 45 pc (L673-7), 258 ± 50 pc (L1014), and 301 ± 55 pc (L1148). We re-evaluated the internal luminosities of the VeLLOs discovered in these seven clouds using the distances estimated from this work. Except for L1014−IRS (L int = 0.15 L ), all other VeLLO candidates are found to be consistent with the definition of a VeLLO (L int ≤ 0.1 L ). In addition to the cores that harbour VeLLO candidates, we also obtained distances to the clouds L323, L675, L676, CB 188, L1122, L1152, L1155, L1157, and L1158, which are located in the directions of the above seven cores. Towards L1521F and L1148, we found evidence of multiple dust layers.

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Probable Association of T Tauri Stars with the L 1014 Dense Core

Cited by 6 publications

References 24 publications

Molecular Outflows Driven by Low-Mass Protostars. I. Correcting for Underestimates When Measuring Outflow Masses and Dynamical Properties

Molecular Outflows Driven by Low-Mass Protostars. I. Correcting for Underestimates When Measuring Outflow Masses and Dynamical Properties

The Detection and Characterization of Centimeter Radio Continuum Emission from the Low‐Mass Protostar L1014‐IRS

Distances to dense cores that contain very low luminosity objects

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