E-Print Archive

There are 4291 abstracts currently viewable.


Advanced Search
Main Page Add New E-Print Submitter
News Help/FAQ About Preferences
Manage Key Phrase
* News 04/04/20 * The archive is using a new backend database. This has thrown up a few SQL errors in the last few days. If you have any issues please email adavey@nso.edu with either the number of eprint you are trying to edit or a link to your preprint.


John C Brown   Submitted: 2015-07-22 13:27

Motivated by recent data on comets in the low corona, we discuss destruction of "sun-impacting" comets in the dense lower atmosphere. Perihelion distances q ≲ R; and masses Mo ≫ 1012 g are required to reach such depths. Extending earlier work on planetary atmosphere impacts to solar conditions, we evaluate the mechanisms and distribution of nucleus mass and energy loss as functions of Mo and q, and of parameter X = 2Q/ CH νo2. Q is the total specific energy for ablative mass-loss, CH the bow-shock heat-transfer efficiency, and νo the solar escape speed (619 km s-1). We discuss factors affecting Q and CH and conclude that, for solar νo , X is most likely < 1 and solar-impactors mostly ablated before decelerating. Sun-impacting comets have energies Moνo2/2 ∼ 2 x 1030 x (Mo/1015 g) erg, (comparable to magnetic flares ∼1029-33). This is released as a localized explosive airburst within a few scale heights H ≃ 200 km of the photosphere, depending weakly on Mo, q and X. For X = 10-2 and Mo = 1015 g, a shallow incidence (e.g., polar ϑ ~ cos-1(0.01)) Kreutz comet airburst occurs at atmospheric density n ~ 3 x 1015 cm-3 x a height of 700 km (3.5 H) above the photosphere (where n = no = 1017 cm-3). The airburst n scales as ~(Mo X cos3 ϑ)1/2 (while height z ( km) = 200 ln(no /n)) so n increases 1000 x (700 km deeper) for vertical entry. Such airbursts drive flare-like phenomena including prompt radiation, hot rising plumes, and photospheric ripples, the observability and diagnostic value of which we discuss.

Authors: John C Brown, Robert W Carlson, Mark P Toner
Projects: SDO-AIA

Publication Status: ApJ (in press)
Last Modified: 2015-07-22 14:53
Go to main E-Print page  Edit Entry  Download Preprint  Submitter's Homepage Delete Entry 

Go to main E-Print pageGo to main E-Print page.
Download PreprintDownload Preprint.
Submitter's HomepageSubmitters Homepage.
Edit EntryEdit Entry.
Delete AbstractDelete abstract.

Abstracts by Author

Related Pages
MSU Solar Physics.
Max Millennium Science Mail Archive.
Max Millennium Message of the Day Mail Archive.
Max Millennium Flare Catalog

Archive Maintainer
Alisdair Davey

© 2000-2020 Solar Physics Group - Montana State University