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Proposal Identification No.:

A2324

Date Received:

2007-Apr-03 14:17:15

Technical Page
Proposal Type: General Category: Sub-Category: Observation Category: Total Time Requested: Minimum Useful Time: Prop osal Title: ABSTRACT: Urgent Astronomy Spectroscopy Solar System 12 Hours 1 hour

Arecibo OH Observations of C/2007 E2 Lovejoy

We propose to observe recently discovered C/2007 E2 Lovejoy in April 2007. This comet is already quite bright (Mv =11) and is at perihelion on 27 March 2007. It becomes visible to the Arecibo telescope on 21 April, with predicted OH line strength between 3-8 mJy. However, comets frequently have outbursts, and brighten on short timescales, so the line could be stronger than predicted. We plan to map the 18-cm OH lines in the cometary coma in a hexagonal pattern around the nucleus position. The line flux gives a measure of the OH production rate, and thus the production of water from the nucleus. The ratio of the nucleus-centered line strength to the off-center coma positions is sensitive to the amount of collisional quenching. The line width is a direct measure of the outflow velocity, which we have measured in 16 comets to date. The velocity depends on the heliocentric distance, overall gas production rate, and varys widely among different comets. The outflow velocity frequently changes at heliocentric distance of 1 AU, so we will be observing this comet at the transition distance.

Name Ellen Howell

Institution NAIC

E-mail ehowell@naic.edu

Phone

Student

Remote Observing Request

X

Observer will travel to AO Remote Observing In Absentia (instructions to operator)

Instrument Setup
L-wide Atmospheric Observation Instruments:

Sp ecial Equipment or setup:

none 1


RFI Considerations Frequency Ranges Planned
1612-1667 MHz

2