Astrometry of H$_2$O Masers in Nearby Star-Forming Regions with VERA I. IRAS 16293$-$2422 in $\rho$ Oph East

Imai, Hiroshi; Nakashima, Kohichiro; Bushimata, Takeshi; Choi, Yoon Kyung; Hirota, Tomoya; Honma, Mareki; Horiai, K.; Inomata, Noritomo; Iwadate, Kenzaburo; Jike, Takaaki; Kameya, Osamu; Kamohara, Ryuichi; Kan-ya, Yukitoshi; Kawaguchi, Noriyuki; Kijima, Minoru; Kobayashi, Hideyuki; Kuji, Seisuke; Kurayama, Tomoharu; Manabe, S.; Miyaji, Takeshi; Nagayama, Tomonori; Nakagawa, Akiharu; Oh, Chung Sik; Omodaká, Toshihiro; Oyama, Tomoaki; Sakai, Satoshi; Sakakibara, Sei-ichiro; Sato, Katsuhisa; Sasao, Tetsuo; Shibata, Katsunori M.; Shimizu, Rie; Shintani, Motonobu; Sofue, Yoshiaki; Sora, Kasumi; Suda, Hiroshi; Tamura, Yoshiaki; Tsushima, Miyuki; Ueno, Yuji; Yamashita, K.

doi:10.1093/pasj/59.6.1107

Cited by 55 publications

(51 citation statements)

References 19 publications

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“…This suggests that the eastern streamer is about 10 pc farther than the core, although more parallax measurements of sources in Lynds 1689 would be required to confirm this. Interestingly, Imai et al (2007) have measured the parallax of water masers in the protostar IRAS16293-2422, located in the northern part of Lynds 1689, and found a value ϖ= -+ 6.5 0.5 1.5 mas, which is consistent within 1 sigma with our parallax estimate for Lynds 1689 ( Figure 14). Notice that we have not considered SFAM 87 in the previous analysis.…”

Section: The Distance To Ophiuchussupporting

confidence: 84%

The Gould’s Belt Distances Survey (Gobelins). I. Trigonometric Parallax Distances and Depth of the Ophiuchus Complex

Ortiz-León

Loinard

Kounkel

et al. 2017

ApJ

167

146

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We present the first results of the Gould's Belt Distances Survey (GOBELINS), a project aimed at measuring the proper motion and trigonometric parallax of a large sample of young stars in nearby regions using multi-epoch Very Long Baseline Array (VLBA) radio observations. Enough VLBA detections have now been obtained for 16 stellar systems in Ophiuchus to derive their parallax and proper motion. This leads to distance determinations for individual stars with an accuracy of 0.3 to a few percent. In addition, the orbits of six multiple systems were modelled by combining absolute positions with VLBA (and, in some cases, near-infrared) angular separations. Twelve stellar systems are located in the dark cloud Lynds1688; the individual distances for this sample are highly consistent with one another and yield a mean parallax for Lynds1688 of v =  7.28 0.06 mas, corresponding to a distance =  d 137.3 1.2 pc. This represents an accuracy greater than 1%. Three systems for which astrometric elements could be measured are located in the eastern streamer (Lynds 1689) and yield an estimate of v =  6.79 0.16 mas, corresponding to a distance =  d 147.3 3.4 pc. This suggests that the eastern streamer is located about 10 pc farther than the core, but this conclusion needs to be confirmed by observations of additional sources in the eastern streamer (currently being collected). From the measured proper motions, we estimate the one-dimensional velocity dispersion in Lynds 1688 to be 2.8±1.8 and 3.0±2.0km s −1 , in R.A. and decl., respectively; these are larger than, but still consistent within s 1 of, those found in other studies.

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Section: The Distance To Ophiuchussupporting

confidence: 84%

The Gould’s Belt Distances Survey (Gobelins). I. Trigonometric Parallax Distances and Depth of the Ophiuchus Complex

Ortiz-León

Loinard

Kounkel

et al. 2017

ApJ

167

146

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“…We note that a second peak is seen between Aa and Ab, which could be associated with the A1 or A2β radio sources ). Identification of this structure is unclear, however, given that no other (sub)millimeter study found a corresponding detection toward these radio sources and that the radio emission in the region has complicated motions from different ejecta (e.g., Imai et al 2007;Pech et al 2010).…”

Section: Continuum Resultsmentioning

confidence: 98%

Dust Polarization toward Embedded Protostars in Ophiuchus with ALMA. II. IRAS 16293-2422

Sadavoy

Myers

Stephens

et al. 2018

ApJ

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We present high-resolution (∼ 35 au) ALMA Band 6 1.3 mm dust polarization observations of IRAS 16293. These observations spatially resolve the dust polarization across the two protostellar sources and toward the filamentary structures between them. The dust polarization and inferred magnetic field have complicated structures throughout the region. In particular, we find that the magnetic field is aligned parallel to three filamentary structures. We characterize the physical properties of the filamentary structure that bridges IRAS 16293A and IRAS 16293B and estimate a magnetic field strength of 23-78 mG using the Davis-Chandrasekhar-Fermi method. We construct a toy model for the bridge material assuming that the young stars dominate the mass and gravitational potential of the system. We find that the expected gas flow to each star is of comparable order to the Alfvén speed, which suggests that the field may be regulating the gas flow. We also find that the bridging material should be depleted in ∼ 10 3 yr. If the bridge is part of the natal filament that formed the stars, then it must have accreted new material. Alternatively, the bridge could be a transient structure.Finally, we show that the 1.3 mm polarization morphology of the optically thick IRAS 16293B system is qualitatively similar to dust self-scattering. Based on similar polarization measurements at 6.9 mm, we propose that IRAS 16293B has produced a substantial population of large dust grains with sizes between 200 and 2000 µm. † Hubble Fellow

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“…Water masers detections have also been reported toward source A through very long baseline (VLBI) observations (Imai et al 2007). The milliarcsecond resolution data revealed a spot exactly over Aa and another one to the SW of it (see Fig.…”

Section: H 2 O Masers and The Sio/co Outflowsmentioning

confidence: 93%

The magnetic field of IRAS 16293-2422 as traced by shock-induced H₂O masers

Alves

Vlemmings

Girart

et al. 2012

A&A

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Context. Shock-induced H 2 O masers are important magnetic field tracers of very high density gas. Water masers are found in both high-and low-mass star-forming regions, and are a powerful tool for comparing magnetic field morphologies in both mass regimes. Aims. We present one of the first magnetic field determinations for the low-mass protostellar core IRAS 16293-2422 at volume densities as high as 10 8−10 cm −3 . Our goal is to determine wether the collapsing regime of this source is controlled by magnetic fields or other factors such as turbulence. Methods. We used the Very Large Array (VLA) to carry out spectropolarimetric observations of the 22 GHz Zeeman emission from H 2 O masers. From the Stokes V line profile, we are then able to estimate the magnetic field strength in the dense regions around the protostar. Results. A blend of at least three maser features can be inferred from our relatively high spatial resolution data set (∼0.1 ), which is reproduced as a clear non-Gaussian line profile. The emission is very stable in terms of polarization fraction and position angle across the channels. The maser spots are aligned with some components of the complex outflow configuration of IRAS 16293-2422, and are excited in zones of compressed gas produced by shocks. The post-shock particle density is in the range of 1−3 × 10 9 cm −3 , consistent with typical water-maser pumping densities. Zeeman emission is produced by a very strong line-of-sight magnetic field (B ∼ 113 mG). Conclusions. The magnetic field pressure derived from our data is comparable to the ram pressure of the outflow dynamics. This indicates that the magnetic field is energetically important to the dynamical evolution of IRAS 16293-2422.

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Astrometry of H$_2$O Masers in Nearby Star-Forming Regions with VERA I. IRAS 16293$-$2422 in $\rho$ Oph East

Cited by 55 publications

References 19 publications

The Gould’s Belt Distances Survey (Gobelins). I. Trigonometric Parallax Distances and Depth of the Ophiuchus Complex

The Gould’s Belt Distances Survey (Gobelins). I. Trigonometric Parallax Distances and Depth of the Ophiuchus Complex

Dust Polarization toward Embedded Protostars in Ophiuchus with ALMA. II. IRAS 16293-2422

The magnetic field of IRAS 16293-2422 as traced by shock-induced H₂O masers

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Astrometry of H$_2$O Masers in Nearby Star-Forming Regions with VERA I. IRAS 16293$-$2422 in $\rho$ Oph East

Cited by 55 publications

References 19 publications

The Gould’s Belt Distances Survey (Gobelins). I. Trigonometric Parallax Distances and Depth of the Ophiuchus Complex

The Gould’s Belt Distances Survey (Gobelins). I. Trigonometric Parallax Distances and Depth of the Ophiuchus Complex

Dust Polarization toward Embedded Protostars in Ophiuchus with ALMA. II. IRAS 16293-2422

The magnetic field of IRAS 16293-2422 as traced by shock-induced H2O masers

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The magnetic field of IRAS 16293-2422 as traced by shock-induced H₂O masers