HST mid-ultraviolet spectroscopy of comet 46P/Wirtanen during its approach to perihelion in 1996-1997

Details HST mid-ultraviolet spectroscopy of comet 46P/Wirtanen during its approach to perihelion in 1996-1997 HST mid-ultraviolet spectroscopy of comet 46P/Wirtanen during its approach to perihelion in 1996-1997

Jul 1998

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998a%26a...335l..30s&link_type=abstract

Astronomy and Astrophysics, v.335, p.L30-L36 (1998)

Astronomy and Astrophysics

Astrophysics

17

Comets: General, Comets: Individual: Wirtanen, Ultraviolet: Solar System

Scientific paper

We have used the Hubble Space Telescope Faint Object Spectrograph to observe the mid-UV spectrum of the ROSETTA mission target comet, 46P/Wirtanen, on three dates during the comet's apparition in 1996 and early 1997. During this time the comet moved inward from a heliocentric distance near 2.7 AU to 1.3 AU. The first measurement (22.7 July 1996) detected only reflected solar continuum; based on these measurements, we set an upper limit on the nuclear radius of 1.45 km. A second measurement (25.9 Aug 1996) detected this reflected continuum, as well as weak OH (0-0) emission; the third measurement (15.2 Jan 1997) detected three OH bands at high signal-to-noise (the 0-0, the 1-0, and the 1-1), along with emission features from the CS radical and the CO_2(+) ion; upper limits on their emission brightness and production rate of C_2 was set. Our key findings are as follows: The data indicate that Q(H_2O) varies like R(-4.9+/-0.25) inside 2.5 AU, and that the CS_2/H_2O production ratio at 1.3 AU is close to 3*E(-4) . We also found that the 2600-3200 Angstroms mid-UV coma color slope is more neutral ( ~ 25%/1000 Angstroms) than typical comets ( ~ 40-70%/1000 Angstroms, but is steeper than Wirtanen's own visible-wavelength color slope. Wirtanen's CS_2/H_2O production ratio is near the low end of the range observed to date. Afrho was estimated from the data as a measure of dust production; we found Afrho (2950 Angstroms) values of 15, 18, and 15 cm, respectively, for the three FOS datasets, after correction for the estimated flux contribution of the nucleus. Interestingly, we found that production of dust, to which the UV is sensitive, did not appear to vary by more than a factor of about two with heliocentric distance over the 2.7 to 1.3 AU range, despite a factor of 50 variation in the production of H_2O. Wirtanen appears to be a small, but relatively normal comet. However, Wirtanen's ratio of dust (i.e., Afrho ) to H_2O production is smaller than in >90% of the 85 comets in A'Hearn et al.'s (1995) large sample.

Affiliated with

Also associated with

No associations

Rating

HST mid-ultraviolet spectroscopy of comet 46P/Wirtanen during its approach to perihelion in 1996-1997 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with HST mid-ultraviolet spectroscopy of comet 46P/Wirtanen during its approach to perihelion in 1996-1997, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and HST mid-ultraviolet spectroscopy of comet 46P/Wirtanen during its approach to perihelion in 1996-1997 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1341197