Formation of jets in Comet 19P/Borrelly by subsurface geysers

Roger Yelle, Laurence A. Soderblom, J. Randy Jokipii

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Observations of the inner coma of Comet 19P/Borrelly with the camera on the Deep Space 1 spacecraft revealed several highly collimated dust jets emanating from the nucleus. The observed jets can be produced by acceleration of evolved gas from a subsurface cavity through a narrow orifice to the surface. As long as the cavity is larger than the orifice, the pressure in the cavity will be greater than the ambient pressure in the coma and the flow from the geyser will be supersonic. The gas flow becomes collimated as the sound speed is approached and dust entrainment in the gas flow creates the observed jets. Outside the cavity, the expanding gas loses its collimated character, but the density drops rapidly decoupling the dust and gas, allowing the dust to continue in a collimated beam. The hypothesis proposed here can explain the jets seen in the inner coma of Comet 1P/Halley as well, and may be a primary mechanism for cometary activity.

Original languageEnglish (US)
Pages (from-to)30-36
Number of pages7
JournalIcarus
Volume167
Issue number1
DOIs
StatePublished - Jan 2004

Fingerprint

geysers
comets
comet
coma
cavity
dust
cavities
orifices
gas flow
gases
gas
geyser
Halley's comet
deep space
entrainment
decoupling
spacecraft
cameras
nuclei
acoustics

Keywords

  • Comae
  • Comets
  • Jets

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Formation of jets in Comet 19P/Borrelly by subsurface geysers. / Yelle, Roger; Soderblom, Laurence A.; Jokipii, J. Randy.

In: Icarus, Vol. 167, No. 1, 01.2004, p. 30-36.

Research output: Contribution to journalArticle

Yelle, Roger ; Soderblom, Laurence A. ; Jokipii, J. Randy. / Formation of jets in Comet 19P/Borrelly by subsurface geysers. In: Icarus. 2004 ; Vol. 167, No. 1. pp. 30-36.
@article{c0841dfed8734484a8c787e68a4c0e73,
title = "Formation of jets in Comet 19P/Borrelly by subsurface geysers",
abstract = "Observations of the inner coma of Comet 19P/Borrelly with the camera on the Deep Space 1 spacecraft revealed several highly collimated dust jets emanating from the nucleus. The observed jets can be produced by acceleration of evolved gas from a subsurface cavity through a narrow orifice to the surface. As long as the cavity is larger than the orifice, the pressure in the cavity will be greater than the ambient pressure in the coma and the flow from the geyser will be supersonic. The gas flow becomes collimated as the sound speed is approached and dust entrainment in the gas flow creates the observed jets. Outside the cavity, the expanding gas loses its collimated character, but the density drops rapidly decoupling the dust and gas, allowing the dust to continue in a collimated beam. The hypothesis proposed here can explain the jets seen in the inner coma of Comet 1P/Halley as well, and may be a primary mechanism for cometary activity.",
keywords = "Comae, Comets, Jets",
author = "Roger Yelle and Soderblom, {Laurence A.} and Jokipii, {J. Randy}",
year = "2004",
month = "1",
doi = "10.1016/j.icarus.2003.08.020",
language = "English (US)",
volume = "167",
pages = "30--36",
journal = "Icarus",
issn = "0019-1035",
publisher = "Academic Press Inc.",
number = "1",

}

TY - JOUR

T1 - Formation of jets in Comet 19P/Borrelly by subsurface geysers

AU - Yelle, Roger

AU - Soderblom, Laurence A.

AU - Jokipii, J. Randy

PY - 2004/1

Y1 - 2004/1

N2 - Observations of the inner coma of Comet 19P/Borrelly with the camera on the Deep Space 1 spacecraft revealed several highly collimated dust jets emanating from the nucleus. The observed jets can be produced by acceleration of evolved gas from a subsurface cavity through a narrow orifice to the surface. As long as the cavity is larger than the orifice, the pressure in the cavity will be greater than the ambient pressure in the coma and the flow from the geyser will be supersonic. The gas flow becomes collimated as the sound speed is approached and dust entrainment in the gas flow creates the observed jets. Outside the cavity, the expanding gas loses its collimated character, but the density drops rapidly decoupling the dust and gas, allowing the dust to continue in a collimated beam. The hypothesis proposed here can explain the jets seen in the inner coma of Comet 1P/Halley as well, and may be a primary mechanism for cometary activity.

AB - Observations of the inner coma of Comet 19P/Borrelly with the camera on the Deep Space 1 spacecraft revealed several highly collimated dust jets emanating from the nucleus. The observed jets can be produced by acceleration of evolved gas from a subsurface cavity through a narrow orifice to the surface. As long as the cavity is larger than the orifice, the pressure in the cavity will be greater than the ambient pressure in the coma and the flow from the geyser will be supersonic. The gas flow becomes collimated as the sound speed is approached and dust entrainment in the gas flow creates the observed jets. Outside the cavity, the expanding gas loses its collimated character, but the density drops rapidly decoupling the dust and gas, allowing the dust to continue in a collimated beam. The hypothesis proposed here can explain the jets seen in the inner coma of Comet 1P/Halley as well, and may be a primary mechanism for cometary activity.

KW - Comae

KW - Comets

KW - Jets

UR - http://www.scopus.com/inward/record.url?scp=1642461611&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=1642461611&partnerID=8YFLogxK

U2 - 10.1016/j.icarus.2003.08.020

DO - 10.1016/j.icarus.2003.08.020

M3 - Article

AN - SCOPUS:1642461611

VL - 167

SP - 30

EP - 36

JO - Icarus

JF - Icarus

SN - 0019-1035

IS - 1

ER -