A Near-Infrared Spectroscopic Survey of Class I Protostars

Connelley, Michael S.; Greene, Thomas P.

doi:10.1088/0004-6256/140/5/1214

Cited by 138 publications

(199 citation statements)

References 67 publications

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“…Our targets do, however, span a wide range of millimeter fluxes (Motte & André 2001;Jørgensen et al 2009;Eisner 2012), so they should span a range of masses of circumstellar material. They also span a range of spectral types (M6-K4; White & Hillenbrand 2004;Doppmann et al 2005;Connelley & Greene 2010) and scattered light morphologies (e.g., Padgett et al 1999;Stark et al 2006;Gramajo et al 2010). …”

Section: Sample Selectionmentioning

confidence: 99%

“…The majority of the sources in our system are K-or M-type stars (White & Hillenbrand 2004;Doppmann et al 2005;Connelley & Greene 2010), so a temperature of 4000 K is a reasonable assumption. We may, however, explore varying the protostellar temperature in future works.…”

Section: Pre-main-sequence Starmentioning

confidence: 99%

“…As such, when comparing disk mass distributions, we must take care to ensure that our samples have similar stellar host properties; otherwise, our disk mass measurements may be biased. We have used spectral types measured for seven of our targets (Doppmann et al 2005;Connelley & Greene 2010) and a direct mass measurement of an eighth to estimate stellar host masses for our sample. We compare these masses with the Class II stellar masses using two-sample tests and find that = -p 0.1 0.19, indicating that we cannot distinguish between the stellar populations.…”

Section: Class I Versus Class Ii Disk Massesmentioning

confidence: 99%

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Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud

Sheehan

Eisner

2017

ApJ

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Class I protostars are thought to represent an early stage in the lifetime of protoplanetary disks, when they are still embedded in their natal envelope. Here we measure the disk masses of 10 Class I protostars in the Taurus Molecular Cloud to constrain the initial mass budget for forming planets in disks. We use radiative transfer modeling to produce synthetic protostar observations and fit the models to a multi-wavelength data set using a Markov Chain Monte Carlo fitting procedure. We fit these models simultaneously to our new Combined Array for Research in Millimeter-wave Astronomy 1.3 mm observations that are sensitive to the wide range of spatial scales that are expected from protostellar disks and envelopes so as to be able to distinguish each component, as well as broadband spectral energy distributions compiled from the literature. We find a median disk mass of  M 0.018 on average, more massive than the Taurus Class II disks, which have median disk mass of~ M 0.0025 . This decrease in disk mass can be explained if dust grains have grown by a factor of 75 in grain size, indicating that by the Class II stage, at a few Myr, a significant amount of dust grain processing has occurred. However, there is evidence that significant dust processing has occurred even during the Class I stage, so it is likely that the initial mass budget is higher than the value quoted here.

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Section: Sample Selectionmentioning

confidence: 99%

Section: Pre-main-sequence Starmentioning

confidence: 99%

Section: Class I Versus Class Ii Disk Massesmentioning

confidence: 99%

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Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud

Sheehan

Eisner

2017

ApJ

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“…Further, FU Orionis-like stars have not been observed to clearly show Br-γ emission. In this regard, Connelley & Greene (2010) speculate that the relationship between Br-γ emission line flux and mass accretion collapses at very high mass accretion rates. Hence, there is a possibility that S9 could be a post-outburst object with the spectrum showing features of transition to that of a later spectral type.…”

Section: Near-infrared Identification Of Cluster Membersmentioning

confidence: 97%

Dust and gas environment of the young embedded cluster IRAS 18511+0146

Vig

Testi

Walmsley

et al. 2017

A&A

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Context. Since massive and intermediate mass stars form in clusters, a comparative investigation of the environments of the young embedded cluster members can reveal significant information about the conditions under which stars form and evolve. Aims. IRAS 18511+0146 is a young embedded (proto)cluster located at 3.5 kpc surrounding what appears to be an intermediate mass protostar. In this paper, we investigate the nature of cluster members (two of which are believed to be the most massive and luminous) using imaging and spectroscopy in the near and mid-infrared. In particular, we examine the three brightest mid-infrared objects and two among these are believed to be most massive ones driving the luminosity of this region. Methods. Near-infrared spectroscopy of nine objects (bright in K bands) towards IRAS 18511+0146 has been carried out. Several cluster members have also been investigated in the mid-infrared using spectroscopic and imaging with VISIR on the VLT. Far-infrared images from the Herschel Hi-GAL survey have been used to construct the column density and temperature maps of the region. Results. The brightest point-like object associated with IRAS 18511+0146 is referred to as S7 in the present work (designated UGPS J185337.88+015030.5 in the UKIRT Galactic Plane survey). S7 is likely the most luminous object in the cluster as it is bright at all wavelengths ranging from the near-infrared to millimetre. Seven of the nine objects show rising spectral energy distributions (SED) in the near-infrared, with four objects showing Br-γ emission. Three members: S7, S10 (also UGPS J185338.37+015015.3) and S11 (also UGPS J185338.72+015013.5) are bright in mid-infrared with diffuse emission being detected in the vicinity of S11 in PAH bands. Silicate absorption is detected towards these three objects, with an absorption maximum between 9.6 and 9.7 µm, large optical depths (1.8 − 3.2), and profile widths of 1.6 − 2.1 µm. The silicate profiles of S7 and S10 are similar, in contrast to S11 (which has the largest width and optical depth). The cold dust emission peaks at S7, with temperature at 26 K and column density N(H 2 )∼ 7 × 10 22 cm −2 . The bolometric luminosity of IRAS 18511 region is L∼ 1.8 × 10 4 L ⊙ . S7 is the main contributor to the bolometric luminosity, with L (S7) 10 4 L ⊙ . Conclusions. S7 is a high mass protostellar object with ionised stellar winds, evident from the correlation between radio and bolometric luminosity as well as the asymmetric Br-γ profile. The differences in silicate profiles of S7 and S11 could be due to different radiation environment as we believe the former to be more massive and in an earlier phase than the latter.

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“…That is, sources satisfying K − [8.0] > 3.9 were regarded as Class I, 1.14 < K − [8.0] < 3.9 as Class II, and −0.26 < K − [8.0] < 1.14 as Class III. The JHK-bands magnitudes were taken from the 2MASS Catalog or additional references (Kraus et al 2007;Connelley & Greene 2010;Moneti & Zinnecker 1991;Chavarría et al 2000). For the sources lacking in the SED fitting (Section 4.1), the A V values for the color correlation were taken from previous studies (Furlan et al 2011;Kraus & Hillenbrand 2009a;Wahhaj et al 2010;Chavarría et al 2000;Evans et al 2009;McClure et al 2010;Currie & Sicilia-Aguilar 2011;Bontemps et al 2001).…”

Section: Our Sample Of Disk-bearing Starsmentioning

confidence: 99%

Study of infrared excess from circumstellar disks in binaries with Spitzer/IRAC

Itoh

Fukagawa

Shibai

et al. 2015

Publications of the Astronomical Society of Japan

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The presence of excess emission at 3.6-8.0 µm was investigated in a sample of 27 binary systems located in two nearby star-forming regions, Taurus and Ophiuchus, by using Spitzer/Infrared Array Camera (IRAC) archival data. Angular (Projected) separations for the binaries are greater than 2 ′′ (∼280 AU), which allowed us to perform spatially resolved photometry of individual primary and secondary sources. The measured occurrence of infrared excess suggests that binarity plays a role in the evolution of circumstellar disks, even at such wide binary separations. Most of the binaries have excess emission from both the circumprimary and circumsecondary disks, or show photospheric levels for both components at all four wavelengths of IRAC. On the other hand, four systems (17 +11 −8 %, designated by "mixed" systems) exhibit excess emission from a single binary component. This ratio is significantly smaller than that predicted by the random pairing of single stars, suggesting that circumprimary and circumsecondary disks are synchronously dispersed. In addition, the excess frequencies (EFs) of primary and secondary sources with a projected distance of a p ≃ 280-450 AU are 100 +0 −17 % and 91 +8 −18 %, respectively, and significantly higher than that of single stars (70 ± 5%). We made a simple model describing the EF distribution as a function of the disk outer radius, R out . Comparisons with observations using the Kolmogorov-Smirnov test show that the observational data are consistent with the model when the EF ≃ 1 region is found at R out ∼ 30-100 AU. This disk radius is smaller than that typically estimated for single stars. The high EF of circumstellar disks with these radii may indicate a prolonged lifetime of dust in binary systems possibly because smaller disks counteract mass loss by photoevaporation.

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A Near-Infrared Spectroscopic Survey of Class I Protostars

Cited by 138 publications

References 67 publications

Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud

Disk Masses for Embedded Class I Protostars in the Taurus Molecular Cloud

Dust and gas environment of the young embedded cluster IRAS 18511+0146

Study of infrared excess from circumstellar disks in binaries with Spitzer/IRAC

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