Abstract
Spatial profiles of C2, CN, NH2, and O(1D) in comet P/Halley taken on 1986 March 1.54 and 2.55 and April 14.32 and 15.30 clearly show the effect of the 7 day periodic variation seen in photometric observations. With a time-dependent model based upon the light curve and employing standard scale lengths for each species reduced to the appropriate heliocentric distance, we are able to reproduce the highly variable profiles for all species. We computed the phase lag and amplitude correction between the actual gas production at the nucleus and the temporal/spatial filter imposed by the finite aperture photometry. For early March we find a phase lag and amplitude correction of 12 hr and -9%, respectively, whereas in mid-April the values are 6 hr and -27%. The same phase lag and amplitude correction work equally well for all four species despite their wide variation in photochemical lifetimes for production and decay. The same model integrated over circular apertures is able to reproduce the entire published March and April photometric light curves for C2. Our results require the use of the 7.60 day period for the March data as opposed to the 7.37 day period that is relevant for the April data, in agreement with the published analysis of the photometric data. Our results will help to reconcile the placement of active areas on the surface of Halley's comet with various remote observations and spacecraft images of the nucleus.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 790-797 |
| Number of pages | 8 |
| Journal | Astrophysical Journal |
| Volume | 409 |
| Issue number | 2 |
| State | Published - 1993 |
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Keywords
- Comets: Individual (Halley)
- Molecular processes
ASJC Scopus subject areas
- Space and Planetary Science
Cite this
P/Halley : Effects of time-dependent production rates on spatial emission profiles. / Combi, Michael R.; Fink, Uwe -.
In: Astrophysical Journal, Vol. 409, No. 2, 1993, p. 790-797.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - P/Halley
T2 - Effects of time-dependent production rates on spatial emission profiles
AU - Combi, Michael R.
AU - Fink, Uwe -
PY - 1993
Y1 - 1993
N2 - Spatial profiles of C2, CN, NH2, and O(1D) in comet P/Halley taken on 1986 March 1.54 and 2.55 and April 14.32 and 15.30 clearly show the effect of the 7 day periodic variation seen in photometric observations. With a time-dependent model based upon the light curve and employing standard scale lengths for each species reduced to the appropriate heliocentric distance, we are able to reproduce the highly variable profiles for all species. We computed the phase lag and amplitude correction between the actual gas production at the nucleus and the temporal/spatial filter imposed by the finite aperture photometry. For early March we find a phase lag and amplitude correction of 12 hr and -9%, respectively, whereas in mid-April the values are 6 hr and -27%. The same phase lag and amplitude correction work equally well for all four species despite their wide variation in photochemical lifetimes for production and decay. The same model integrated over circular apertures is able to reproduce the entire published March and April photometric light curves for C2. Our results require the use of the 7.60 day period for the March data as opposed to the 7.37 day period that is relevant for the April data, in agreement with the published analysis of the photometric data. Our results will help to reconcile the placement of active areas on the surface of Halley's comet with various remote observations and spacecraft images of the nucleus.
AB - Spatial profiles of C2, CN, NH2, and O(1D) in comet P/Halley taken on 1986 March 1.54 and 2.55 and April 14.32 and 15.30 clearly show the effect of the 7 day periodic variation seen in photometric observations. With a time-dependent model based upon the light curve and employing standard scale lengths for each species reduced to the appropriate heliocentric distance, we are able to reproduce the highly variable profiles for all species. We computed the phase lag and amplitude correction between the actual gas production at the nucleus and the temporal/spatial filter imposed by the finite aperture photometry. For early March we find a phase lag and amplitude correction of 12 hr and -9%, respectively, whereas in mid-April the values are 6 hr and -27%. The same phase lag and amplitude correction work equally well for all four species despite their wide variation in photochemical lifetimes for production and decay. The same model integrated over circular apertures is able to reproduce the entire published March and April photometric light curves for C2. Our results require the use of the 7.60 day period for the March data as opposed to the 7.37 day period that is relevant for the April data, in agreement with the published analysis of the photometric data. Our results will help to reconcile the placement of active areas on the surface of Halley's comet with various remote observations and spacecraft images of the nucleus.
KW - Comets: Individual (Halley)
KW - Molecular processes
UR - http://www.scopus.com/inward/record.url?scp=12044253187&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=12044253187&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:12044253187
VL - 409
SP - 790
EP - 797
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
ER -