The Distribution of Dust Clouds in the Interstellar Medium

Dring, A. R.; Murthy, Jayant; Henry, R. C.; Walker, H. J.

doi:10.1086/176771

Cited by 9 publications

(13 citation statements)

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“…To FIG. 2.ÈComparison of the angular radius of cirrus hot spots for stars in common between Dring et al (1996) and Gaustad & Van Buren (1993). If agreement was perfect, all the points would fall along the dashed line.…”

Section: Cirrus Hot Spots?mentioning

confidence: 90%

“…During such an encounter, as is currently occurring in the Pleiades (Jura 1977 ;White & Bally 1993), there is enhanced infrared emission in the direction of the star. Gaustad & van Buren (1993) have found that about 15% of O and B stars illuminate nearby dust sufficiently to be detected in IRAS scans as cirrus hot spots ; Dring et al (1996) derive a smaller Ðlling factor of about 2%. Although there is disagreement about the frequency of the e †ect because the infrared colors of the excesses resemble those of the cirrus hot spots, the result that 8% of all luminosity class III red giants possess at least some small infrared excess (Plets et al 1997) might be explained as cirrus hot spots.…”

Section: Cirrus Hot Spots?mentioning

confidence: 99%

“…In Figure 2, we show a comparison between the angular radius of the cirrus hot spot measured by Dring et al (1996) and Gaustad & Van Buren (1993) for the stars that are in common in both lists. While the two groups usually agree to better than a factor of 2, there is substantial scatter.…”

Section: Fig 4èfor the Same Stars As Inmentioning

confidence: 99%

“…In this paper we examine the data for the nearest, best established examples of red giants with circumstellar dust in order to decide which, if either, proposed model is more likely to be correct. We also examine a third possibility, that the dust infrared excesses around at least some of the red giants is the result of a cirrus hot spot that can be produced when a star happens to lie near an interstellar dust cloud, a phenomenon that has been investigated for O and B type stars (Murthy, Walker, & Henry 1992 ;Gaustad & Van Buren 1993 ;Dring et al 1996) as well as for a few very luminous red giants on the asymptotic giant branch (Le Bertre et al 1998). In°2 we describe the properties of the best examples of red giant stars with circumstellar dust.…”

Section: Introductionmentioning

confidence: 99%

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Dust around First‐Ascent Red Giants

Jura

1999

ApJ

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We examine models for the physical conditions in the dust envelopes around the closest and most conspicuous examples of luminosity class III red giants with infrared excesses such as d And.(1) It has been previously suggested that the dust is sporadically ejected from the stars, but for most such stars, this model seems unlikely. (2) Another possibility is that in some cases we might be witnessing emission from interstellar dust that happens to be near the star, a "" cirrus hot spot. ÏÏ Since 70% of the red giants with infrared excesses lie within 100 pc of the Galactic plane where this phenomenon must sometimes occur, many of the excesses might be explained by this e †ect. However, a difficulty with this model for at least a few bright sources is that if the clouds have a uniform density, we expect sizes at 60 km that are about a factor of 10 larger than found for the best studied examples. It seems likely that some class III giants do possess circumstellar dust. (3) The inferred mass of dust around some class III red giants is larger than 1026 g, more matter than would be expected when a Vega-type star evolves o † the main sequence. Because the dust is inferred to be more than 100 AU from the star, we hypothesize that the large inferred dust masses is the result of the disintegration of comets. This model can be tested by using the Space Infrared Telescope Facility to measure the 60 km sizes.

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Section: Cirrus Hot Spots?mentioning

confidence: 90%

Section: Cirrus Hot Spots?mentioning

confidence: 99%

Section: Fig 4èfor the Same Stars As Inmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dust around First‐Ascent Red Giants

Jura

1999

ApJ

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“…The results obtained differ, and independent of these differences, the scattering varies tremendously from place to place in the galaxy. We refer the reader to Dring et al (1996) and references therein for a discussion of these results.…”

Section: Thermal Infraredmentioning

confidence: 94%

The 1997 reference of diffuse night sky brightness

Leinert

Bowyer

Haikala

et al. 1998

Astron. Astrophys. Suppl. Ser.

450

436

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Abstract. In the following we present material in tabular and graphical form, with the aim to allow the nonspecialist to obtain a realistic estimate of the diffuse night sky brightness over a wide range of wavelengths from the far UV longward of Lyα to the far-infrared. At the same time the data are to provide a reference for cases in which background brightness has to be discussed, including the planning for space observations and the issue of protection of observatory sites. We try to give a critical presentation of the status at the beginning of 1997.

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The λ Bootis phenomenon: interaction between a star and a diffuse interstellar cloud

Kamp¹,

Paunzen²

2002

Monthly Notices of the Royal Astronomical Society

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The λ Bootis stars, a group of late B to early F-type population I stars, have surface abundances that resemble the general metal depletion pattern found in the interstellar medium. Inspired by the recent result that the fundamental parameters of these peculiar stars differ in no respect from a comparison sample of normal stars, the hypothesis of an interaction between a star and a diffuse interstellar cloud is considered as a possible explanation of the peculiar abundance pattern. It is found that such a scenario is able to explain the selective accretion of interstellar gas depleted in condensable elements as well as the spectral range of the λ Bootis phenomenon.

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The Distribution of Dust Clouds in the Interstellar Medium

Cited by 9 publications

References 0 publications

Dust around First‐Ascent Red Giants

Dust around First‐Ascent Red Giants

The 1997 reference of diffuse night sky brightness

The λ Bootis phenomenon: interaction between a star and a diffuse interstellar cloud

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