Herbig Ae/Be stars - Intermediate-mass stars surrounded by massive circumstellar accretion disks

Hillenbrand, Lynne A.; Strom, S. E.; Vrba, F. J.; Keene, J.

doi:10.1086/171819

Cited by 633 publications

(869 citation statements)

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“…Rapid disk evolution on <1 Myr timescales has produced a significant population of IMPS lacking inner dust disks, as predicted by PW10 and now revealed by their detected X-ray emission and lack of IR excess emission. This supports previous results that the disks around the intermediate-mass progenitors to Herbig Ae/Be stars are destroyed more quickly than those of their low-mass T Tauri analogs (Hillenbrand et al 1992;Haisch et al 2001). We find that the disk lifetime can be parameterized as a negative power-law function of stellar mass with an index d = 1.5.…”

Section: Science Discoveriessupporting

confidence: 91%

“…These values agree very well with reported Herbig Be disk lifetimes (Hillenbrand et al 1992) and massive YSO ages (Mottram et al 2011a), respectively. Hence the power-law parameterization of PW10appears to hold for YSOs across the range from intermediate to high masses.…”

Section: Total Stellar Populationsupporting

confidence: 91%

“…For the full PCM population in the ACIS FOV (Figure 6 Our Chandra observation of M17 SWex has identified a substantial population of very young IMPS with no IR excess. Clearly the inner disk lifetime for IMPS is shorter than the inner disk lifetime of~3 Myr for low-mass T Tauri stars, as numerous previous studies have reported (Hillenbrand et al 1992;Haisch et al 2001;Hernández et al 2007;Roccatagliata et al 2011). PW10 parameterized the disk lifetime t m d ( ) for IMPS in terms of a disk fraction with a power-law mass dependence,…”

Section: Total Stellar Populationmentioning

confidence: 99%

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RAPID CIRCUMSTELLAR DISK EVOLUTION AND AN ACCELERATING STAR FORMATION RATE IN THE INFRARED DARK CLOUD M17 SWex

Povich

Townsley

Robitaille

et al. 2016

ApJ

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We present a catalog of 840 X-ray sources and first results from a 100 ks Chandra X-ray Observatory imaging study of the filamentary infrared (IR) dark cloud G014.225-00.506, which forms the central regions of a larger cloud complex known as the M17 southwest extension (M17 SWex). In addition to the rich population of protostars and young stellar objects with dusty circumstellar disks revealed by archival data from the Spitzer Space Telescope, we discover a population of X-ray-emitting, intermediate-mass pre-main-sequence stars that lack IR excess emission from circumstellar disks. We model the IR spectral energy distributions of this source population to measure its mass function and place new constraints on the destruction timescales for the inner dust disk for 2-8 M ☉ stars. We also place a lower limit on the star formation rate (SFR) and find that it is quite high (  M 0.007 M ☉ yr −1 ), equivalent to several Orion Nebula Clusters in G14.225-0.506 alone, and likely accelerating. The cloud complex has not produced a population of massive, O-type stars commensurate with its SFR. This absence of very massive (20 M ☉ ) stars suggests that either (1) M17 SWex is an example of a distributed mode of star formation that will produce a large OB association dominated by intermediate-mass stars but relatively few massive clusters, or (2) the massive cores are still in the process of accreting sufficient mass to form massive clusters hosting O stars.

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Section: Science Discoveriessupporting

confidence: 91%

Section: Total Stellar Populationsupporting

confidence: 91%

Section: Total Stellar Populationmentioning

confidence: 99%

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RAPID CIRCUMSTELLAR DISK EVOLUTION AND AN ACCELERATING STAR FORMATION RATE IN THE INFRARED DARK CLOUD M17 SWex

Povich

Townsley

Robitaille

et al. 2016

ApJ

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“…The stellar parameters of R CrA are still rather uncertain, ranging from a spectral type of F5 (Hillenbrand et al 1992;Natta et al 1993;Garcia Lopez et al 2006), A5 (Herbig & Bell 1988;Chen et al 1997) to B8 (Bibo et al 1992;Hamaguchi et al 2005). For the distance, we adopt the commonly assumed value of 130 pc (Marraco & Rydgren 1981).…”

Section: Earlier Studies On R Cramentioning

confidence: 99%

Revealing the sub-AU asymmetries of the inner dust rim in the disk around the Herbig Ae star R Coronae Austrinae

Kraus¹,

Hofmann²,

Malbet

et al. 2009

A&A

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Context. Unveiling the structure of the disks around intermediate-mass pre-main-sequence stars (Herbig Ae/Be stars) is essential for our understanding of the star and planet formation process. In particular, models predict that in the innermost AU around the star, the dust disk forms a "puffed-up" inner rim, which should result in a strongly asymmetric brightness distribution for disks seen under intermediate inclination.Aims. Our aim is to constrain the sub-AU geometry of the inner disk around the Herbig Ae star R CrA and search for the predicted asymmetries. Methods. Using the VLTI/AMBER long-baseline interferometer, we obtained 24 near-infrared (H-and K-band) spectrointerferometric observations on R CrA. Observing with three telescopes in a linear array configuration, each data set samples three equally spaced points in the visibility function, providing direct information about the radial intensity profile. In addition, the observations cover a wide position angle range (∼97 • ), also probing the position angle dependence of the source brightness distribution. Results. In the derived visibility function, we detect the signatures of an extended (Gaussian FWHM ∼ 25 mas) and a compact component (Gaussian FWHM ∼ 5.8 mas), with the compact component contributing about two-thirds of the total flux (both in H-and K-band). The brightness distribution is highly asymmetric, as indicated by the strong closure phases (up to ∼40 • ) and the detected position angle dependence of the visibilities and closure phases. To interpret these asymmetries, we employ various geometric as well as physical models, including a binary model, a skewed ring model, and a puffed-up inner rim model with a vertical or curved rim shape. For the binary and vertical rim model, no acceptable fits could be obtained. On the other hand, the skewed ring model and the curved puffed-up inner rim model allow us to simultaneously reproduce the measured visibilities and closure phases. From these models we derive the location of the dust sublimation radius (∼0.4 AU), the disk inclination angle (∼35 • ), and a north-south disk orientation (PA ∼ 180−190 • ). Our curved puffed-up rim model can reproduce reasonably well the interferometric observables and the SED and suggests a luminosity of ∼29 L and the presence of relatively large ( > ∼ 1.2 μm) Silicate dust grains. Our study also reveals discrepancies between the measured interferometric observables and the puffed-up inner rim models, providing important constraints for future refinements of these theoretical models. Perpendicular to the disk, two bow shock-like structures appear in the associated reflection nebula NGC 6729, suggesting that the detected sub-AU size disk is the driving engine of a large-scale outflow. Conclusions. Detecting, for the first time, strong non-localized asymmetries in the inner regions of a Herbig Ae disk, our study supports the existence of a puffed-up inner rim in YSO disks.

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“…It is illuminated by the Herbig Ae/Be star V 380 Ori, a multiple system with a circumsystem disk where the primary is a 100 L B9 star exhibiting strong emission lines (e.g., Leinert et al 1997;Hillenbrand et al 1992;Alecian et al 2009). NGC 1999 features a compact (20-30 ) dark patch (see Fig.…”

Section: Introductionmentioning

confidence: 99%

Hier ist wahrhaftig ein Loch im Himmel

Stanke¹,

Stutz

Tobin

et al. 2010

A&A

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The NGC 1999 reflection nebula features a dark patch with a size of ∼10 000 AU, which has been interpreted as a small, dense foreground globule and possible site of imminent star formation. We present Herschel PACS far-infrared 70 and 160 μm maps, which reveal a flux deficit at the location of the globule. We estimate the globule mass needed to produce such an absorption feature to be a few tenths to a few M . Inspired by this Herschel observation, we obtained APEX LABOCA and SABOCA submillimeter continuum maps, and Magellan PANIC near-infrared images of the region. We do not detect a submillimer source at the location of the Herschel flux decrement; furthermore our observations place an upper limit on the mass of the globule of ∼2.4 × 10 −2 M . Indeed, the submillimeter maps appear to show a flux depression as well. Furthermore, the near-infrared images detect faint background stars that are less affected by extinction inside the dark patch than in its surroundings. We suggest that the dark patch is in fact a hole or cavity in the material producing the NGC 1999 reflection nebula, excavated by protostellar jets from the V 380 Ori multiple system.

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Herbig Ae/Be stars - Intermediate-mass stars surrounded by massive circumstellar accretion disks

Cited by 633 publications

References 0 publications

RAPID CIRCUMSTELLAR DISK EVOLUTION AND AN ACCELERATING STAR FORMATION RATE IN THE INFRARED DARK CLOUD M17 SWex

RAPID CIRCUMSTELLAR DISK EVOLUTION AND AN ACCELERATING STAR FORMATION RATE IN THE INFRARED DARK CLOUD M17 SWex

Revealing the sub-AU asymmetries of the inner dust rim in the disk around the Herbig Ae star R Coronae Austrinae

Hier ist wahrhaftig ein Loch im Himmel

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