Nanodiamonds around HD 97048 and Elias 1

Kerckhoven, C. van; Tielens, A. G. G. M.; Waelkens, Christoffel

doi:10.1051/0004-6361:20011814

Cited by 102 publications

(111 citation statements)

References 60 publications

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“…We note, however, that we are probing different spatial scales and that, overall, the brightness asymmetry in east-west direction is mostly confined to radial distances >0.5 in the PAH filters and not to the MIR continuum (Doucet et al 2007;van Boekel et al 2004;Mariñas et al 2011). Habart et al (2004) showed that emission features at 3.43 and 3.53 μm, which were attributed to hydrogenated diamonds (Van Kerckhoven et al 2002;Habart et al 2004;Guillois et al 1999, and references therein), as well as the nearby continuum emission was slightly extended and most likely arising from the innermost 15 AU of a circumstellar disk seen face-on. Doering et al (2007) used HST/ACS to image the circumstellar surrounding of HD 97048 in the F606W (broad V) filter.…”

Section: Hd 97048 Resolved In Pah Continuum and Gas Emissionmentioning

confidence: 62%

Resolving the inner regions of the HD 97048 circumstellar disk with VLT/NACO polarimetric differential imaging

Quanz

Birkmann

Apai

et al. 2012

A&A

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Context. Circumstellar disks are the cradles of planetary systems and their physical and chemical properties directly influence the planet formation process. Because most planets supposedly form in the inner disk regions, i.e., within a few tens of AU, it is crucial to study circumstellar disks on these scales to constrain the conditions for planet formation. Aims. Our aims are to characterize the inner regions of the circumstellar disk around the young Herbig Ae/Be star HD 97048 in polarized light. Methods. We used VLT/NACO to observe HD 97048 in polarimetric differential imaging (PDI) mode in the H and K s band. This technique offers high-contrast capabilities at very small inner working angles and probes the dust grains on the surface layer of the disk that act as the scattering surface. Results. We spatially resolve the disk around HD 97048 in polarized flux in both filters on scales between ∼0.1 -1.0 corresponding to the inner ∼16-160 AU. Fitting isophots to the flux calibrated H-band image between 13-14 mag/arcsec 2 and 14-15 mag/arcsec 2 , we derive an apparent disk inclination angle of 34 • ± 5 • and 47 • ± 2 • , respectively. The disk position angle in both brightness regimes is almost identical and roughly 80 • . Along the disk major axis the surface brightness of the polarized flux drops from ∼11 mag/arcsec 2 at ∼0.1 (∼16 AU) to ∼15.3 mag/arcsec 2 at ∼1.0 (∼160 AU). The brightness profiles along the major axis are fitted with power-laws falling off as ∝r −1.78±0.02 in H and ∝r −2.34±0.04 in K s . Because the surface brightness decreases more rapidly in K s compared to H, the disks becomes relatively bluer at larger separations, possibly indicating changing dust grain properties as a function of radius. Conclusions. We imaged for the first time the inner ∼0.1 -1.0 (∼16-160 AU) of the surface layer of the HD 97048 circumstellar disk in scattered light, which demonstrates the power of ground-based imaging polarimetry. Our data fill an important gap in a large collection of existing data that include resolved thermal dust and polycyclic aromatic hydrocarbon (PAH) emission and also resolved gas emission lines. HD 97048 therefore is an ideal test case for sophisticated models of circumstellar disks and a prime target for future high-contrast imaging observations.

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Section: Hd 97048 Resolved In Pah Continuum and Gas Emissionmentioning

confidence: 62%

Resolving the inner regions of the HD 97048 circumstellar disk with VLT/NACO polarimetric differential imaging

Quanz

Birkmann

Apai

et al. 2012

A&A

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“…Consequently, they could become visible in emission, if the nano-diamonds would be separated from other grains. In the case of the diamond emission bands seen in the Herbig Ae/Be objects, it has been possible to derive an abundance of the diamonds which, however, is very low (1 part per billion relative to hydrogen, van Kerckhoven et al 2002). This abundance value, however, may reflect only a population of diamond grains in a narrow size range which allows both the stochastic heating process and the presence of well-ordered surfaces.…”

Section: Discussionmentioning

confidence: 99%

“…So far, the only strong observational evidence for the presence of diamonds in other astrophysical environments comes from the identification of the infrared emission bands of hydrogen-saturated diamond surfaces at 3.43 and 3.53 µm in certain Herbig-AeBe objects as well as in the post-AGB star HR 4049 (Guillois et al 1999;van Kerckhoven et al 2002). The earlier identification by Allamandola et al (1992), who suggested nano-diamonds as the source of a 3.47 µm absorption feature seen in dense molecular clouds (protostars), now seems untenable (Brooke et al 1996(Brooke et al , 1999.…”

Section: Introductionmentioning

confidence: 99%

Optical data of meteoritic nano-diamonds from far-ultraviolet to far-infrared wavelengths

Mutschke

Andersen

Jäger

et al. 2004

A&A

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Abstract.We have used different spectroscopic techniques to obtain a consistent quantitative absorption spectrum of a sample of meteoritic nano-diamonds in the wavelength range from the vacuum ultraviolet (0.12 µm) to the far infrared (100 µm). The nano-diamonds have been isolated by a chemical treatment from the Allende meteorite (Braatz et al. 2000, Meteorit. Planet. Sci., 35, 75). Electron energy loss spectroscopy (EELS) extends the optical measurements to higher energies and allows the derivation of the optical constants (n & k) by Kramers-Kronig analysis. The results can be used to restrain observations and to improve current models of the environment where the nano-diamonds are expected to have formed. We also show that the amount of nano-diamond which can be present in space is higher than previously estimated by Lewis et al. (1989, Nature, 339, 117).

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“…They attribute this feature to the presence of crystalline silicate but it could also be a PAH band. References: (1) Van Kerckhoven et al (2002); (2) Meeus et al (2001); (3) Brooke et al (1993); (4) From the spectrum of Tokunaga et al (1991) and Hanner et al (1992) for the 3.3 and 11.3 µm feature, respectively.…”

Section: Summary Of the Observationsmentioning

confidence: 99%

“…d Hanner et al (1994). References: (1) Meeus et al (2001) and references therein; (2) Van Kerckhoven et al (2002) and references therein; (3) for astrophysical parameters Hillenbrand et al (1992) (except for BD+46 • 3471 see Berrilli et al (1992) and for VV Ser see Testi et al (1998)); for PAH emission extension and AIBs detection Brooke et al (1993); for silicate emission features detection Berrilli et al (1992); (4) Ressler & Barsony (2003) and references therein.…”

Section: Introductionmentioning

confidence: 99%

PAHs in circumstellar disks around Herbig Ae/Be stars

Habart

Natta

Krügel

2004

A&A

134

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Abstract. We investigate the presence and properties of PAHs on the surface of circumstellar disks around Herbig Ae/Be stars by comparing the predictions of disk models with observations. We present results of a radiation transfer code for disks heated by the central star, in hydrostatic equilibrium in the vertical direction (flared disks). The dust is a mixture of large grains in thermal equilibrium, transiently heated small grains and PAHs. Special attention is given to the influence of the stellar, disk and PAH properties on the strength of the PAH emission lines and their spatial distribution. The models predict an infrared SED showing PAH features at 3.3, 6.2, 7.7, and 11.3 µm clearly visible above the continuum, and with some of them very strong. The PAH emission, spatially extended, comes mostly from the outer disk region (R ∼ 100 AU) while the continuum emission at similar wavelengths, mostly due to warm large grains, is confined to the innermost disk regions (R ∼ few AU). We compare the model results to infrared observations from ISO and ground-based telescopes of some thirty Herbig Ae/Be stars. Most of the observed PAH features in objects with spectral type later than B9 are well described by our disk models and we discuss in some detail the PAH characteristics one can derive from the existing data. Objects with strong radiation field (generally earlier than about B9) have the 3.3 µm feature (often the only one observed) much weaker than predicted, and we discuss possible explanations (dissipation of the disk, photoevaporation or modification of the PAH properties).

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Nanodiamonds around HD 97048 and Elias 1

Cited by 102 publications

References 60 publications

Resolving the inner regions of the HD 97048 circumstellar disk with VLT/NACO polarimetric differential imaging

Resolving the inner regions of the HD 97048 circumstellar disk with VLT/NACO polarimetric differential imaging

Optical data of meteoritic nano-diamonds from far-ultraviolet to far-infrared wavelengths

PAHs in circumstellar disks around Herbig Ae/Be stars

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