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Post Info TOPIC: Bok Globule B335
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RE: Bok Globule B335
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Title: Discovery of a Hot Corino in the Bok Globule B335
Author: Muneaki Imai, Nami Sakai, Yoko Oya, Ana López-Sepulcre, Yoshimasa Watanabe, Cecilia Ceccarelli, Bertrand Lefloch, Emmanuel Caux, Charlotte Vastel, Claudine Kahane, Takeshi Sakai, Tomoya Hirota, Yuri Aikawa, Satoshi Yamamoto

We report the first evidence of a hot corino in a Bok globule. This is based on the ALMA observations in the 1.2 mm band toward the low-mass Class 0 protostar IRAS 19347+0727 in B335. Saturated complex organic molecules (COMs), CH3CHO, HCOOCH3, and NH2CHO, are detected in a compact region within a few 10 au around the protostar. Additionally, CH3OCH3, C2H5OH, C2H5CN, and CH3COCH3 are tentatively detected. Carbon-chain related molecules, CCH and c-C3H2, are also found in this source, whose distributions are extended over a few 100 au scale. On the other hand, sulfur-bearing molecules CS, SO, and SO2, have both compact and extended components. Fractional abundances of the COMs relative to H2 are found to be comparable to those in known hot-corino sources. Though the COMs lines are as broad as 5-8 km s^-1, they do not show obvious rotation motion in the present observation. Thus, the COMs mainly exist in a structure whose distribution is much smaller than the synthesized beam (0."58 x 0."52).

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Blobrana


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B 335 globule
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Title: A new method of determining distances to dark globules. The distance to B 335
Authors: Sven Olofsson, Göran Olofsson

We observed a test globule, B 335 in U, B, g, r, and I, and together with the 2MASS survey, this data set gives a well-defined spectral energy distribution (SED) of a large number of stars. The SED of each star depends on the interstellar extinction, the distance to the star, and its intrinsic SED. The method is based on the use of stellar atmospheric models to represent the intrinsic SEDs of the stars. Formally, it is then possible to determine the spectral class of each star and thereby its distance. For some of the stars we have optical spectra, allowing us to compare the photometric classification to the spectrometric.
We can identify one star at the front side of the globule. It has a photometric distance of 90 pc. The closest star behind the B 335 globule has a distance of only ~ 120 pc and we therefore determine the distance to B 335 as 90-120 pc. Our deep U image shows a relatively bright south-western rim of the globule, and we investigate whether it might be due to a local enhancement of the radiation field. A candidate source, located 1.5 arcminutes outside our field, would be the field star, HD 184982. This star has an entry in the Hipparcos Catalogue and its distance is 140-200 pc. However, we come to the conclusion that the bright SW rim is more likely due to the wing of the point-spread-function (PSF) of this star.

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Blobrana


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Posts: 131433
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RE: Bok Globule B335
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B335

B335 (object 335 in Barnards catalogue; also known as CB 199) is  an isolated, nearly spherical Bok globule at a distance of ~250pc.
It was the first Bok globule for which conclusive evidence of star formation was observed.

Position(2000): RA 19 37 00, Dec +07 34 28

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Title: Spitzer Observations of Bok Globule B335: Isolated Star Formation Efficiency and Cloud Structure
Authors: Amelia M. Stutz, Mark Rubin, Michael W. Werner, George H. Rieke, John H. Bieging, Jocelyn Keene, Miju Kang, Yancy L. Shirley, K. Y. L. Su, Thangasamy Velusamy, David J. Wilner

We present infrared and millimetre observations of Barnard 335, the prototypical isolated Bok globule with an embedded protostar. Using Spitzer data we measure the source luminosity accurately; we also constrain the density profile of the innermost globule material near the protostar using the observation of an 8.0 um shadow. HHT observations of 12CO 2 --> 1 confirm the detection of a flattened molecular core with diameter ~10000 AU and the same orientation as the circumstellar disk (~100 to 200 AU in diameter). This structure is probably the same as that generating the 8.0 um shadow and is expected from theoretical simulations of collapsing embedded protostars. We estimate the mass of the protostar to be only ~5% of the mass of the parent globule.

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