Comet Observation during the Advent Semester of 2007 Matt Greenwood

Outline Background to Comets Background to Comets “Observing”/Analyzing Comets “Observing”/Analyzing Comets Observed Comets Observed Comets Comet 17P/Holmes Comet 17P/Holmes

Background History History Religious Significance— Messenger of Doom/Omen Religious Significance— Messenger of Doom/Omen Aristotle ( B.C.) Aristotle ( B.C.) 1577—Tycho Brahe 1577—Tycho Brahe ( ) ( )

Background History History Sir Isaac Newton ( ) Edmund Halley ( ) Comet of 1682

Background Composition Composition H, N, O, CH 4, NH 3, CO 2, H 2 O, Silicates (Varies) H, N, O, CH 4, NH 3, CO 2, H 2 O, Silicates (Varies) Structure Structure Nucleus Nucleus Coma Coma Hydrogen Envelope Hydrogen Envelope Tail/s Tail/s Gas (Ion) Tail Gas (Ion) Tail Dust Tail Dust Tail Source:

Background Comet Nomenclature Comet Nomenclature P/—Periodic Comet ex. 1P/1682 Q1(Halley) P/—Periodic Comet ex. 1P/1682 Q1(Halley) C/—Non-Periodic Comet ex. C/1995 O1(Hale- Bopp) C/—Non-Periodic Comet ex. C/1995 O1(Hale- Bopp) X/—No Reliable Orbit X/—No Reliable Orbit D/—Broken Up/Lost Comet D/—Broken Up/Lost Comet A/—Mistakenly Identified Comet A/—Mistakenly Identified Comet Proper Name vs. Formal Name Proper Name vs. Formal Name

Background Orbit Orbit Elliptical path Perihelion vs. Aphelion Long-period vs. Short-period Long-period vs. Short-period

Background Source:

Background

Background The Solar and Heliospheric Observatory (SOHO) The Solar and Heliospheric Observatory (SOHO) 1,373 Comets 1,373 Comets 190 Short Period 190 Short Period Source:

Background Comet P/2007 R5 (SOHO) Comet P/2007 R5 (SOHO) Comet P/2007 R5Comet P/2007 R5 or Comet P/2007 R5Comet P/2007 R5

Background Porous/Active Nucleus Porous/Active Nucleus Sunlit Side Sunlit Side Intermittent “Activity” Intermittent “Activity” Altering Orbits Altering Orbits Perturbations Perturbations

Background Stardust Stardust 89P/ Wild 2 89P/ Wild 2 Predicted Composition vs. Observed Composition Predicted Composition vs. Observed Composition

Background Origins Origins Kuiper Belt Kuiper Belt Oort Cloud Oort Cloud Source:

Observing/Analyzing Comets Minor Planet Center (MPC) Minor Planet Center (MPC) Desired Observations/Updated Orbits Desired Observations/Updated Orbits Right Ascension and Declination Right Ascension and Declination Magnitude and Velocity Magnitude and Velocity

Observing/Analyzing Comets

12inch LX200 (2) 12inch LX200 (2) 12inch LX200R (2) 12inch LX200R (2) 14inch RCX400 14inch RCX400

Observing/Analyzing Comets Astrometrica Astrometrica Input of Coordinates Input of Coordinates Inspection of Comet and Position Inspection of Comet and Position Guide Star vs. Manual Adjustments Guide Star vs. Manual Adjustments Time/Image Intervals Time/Image Intervals

Observing/Analyzing Comets Processing Processing Dark Field Flat Field Stacking Images “Blinking” C/2006 M4

Observed Comets P/2007 T2 (Kowalski) P/2007 T2 (Kowalski) Semi-major Axis: 3.11 AU Semi-major Axis: 3.11 AU Eccentricity: 0.77 Eccentricity: 0.77 Inclination: 9.92° Inclination: 9.92°

Observed Comets P/2007 R3 (Gibbs) P/2007 R3 (Gibbs) Semi-major Axis: 4.83 AU Semi-major Axis: 4.83 AU Eccentricity: 0.55 Eccentricity: 0.55 Inclination: 3.17° Inclination: 3.17°

Observed Comets P/2007 T4 (Gibbs) P/2007 T4 (Gibbs) Semi-major Axis: 5.09 AU Semi-major Axis: 5.09 AU Eccentricity: 0.61 Eccentricity: 0.61 Inclination: 23.86° Inclination: 23.86°

Observed Comets C/2007 T5 (Gibbs) C/2007 T5 (Gibbs) Perihelion: 4.19 AU Perihelion: 4.19 AU Eccentricity: 1.0 Eccentricity: 1.0 Inclination: 45.26° Inclination: 45.26°

Observed Comets P/2007 T6 (Catalina) P/2007 T6 (Catalina) Semi-major Axis: 4.49 AU Semi-major Axis: 4.49 AU Eccentricity: 0.50 Eccentricity: 0.50 Inclination: 22.15° Inclination: 22.15°

Observed Comets C/2007 W1 (Boattini) C/2007 W1 (Boattini) Perihelion: 0.84 AU Perihelion: 0.84 AU Eccentricity: 0.99 Eccentricity: 0.99 Inclination: 9.89° Inclination: 9.89°

Observed Comets P/2007 W2 (LINEAR) P/2007 W2 (LINEAR) Semi-major Axis: 4.01 AU Semi-major Axis: 4.01 AU Eccentricity: 0.57 Eccentricity: 0.57 Inclination: 11.11° Inclination: 11.11°

Observed Comets C/2007 U1 (LINEAR) C/2007 U1 (LINEAR) Perihelion: 3.33 AU Perihelion: 3.33 AU Eccentricity: 1.00 Eccentricity: 1.00 Inclination: ° Inclination: °

Comet 17P/Holmes Source:

Comet 17P/Holmes November 6, 1892 November 6, 1892 Previous Outbursts Previous Outbursts Dust Avalanche Dust Avalanche

Comet 17P/Holmes

Observation Date: October,

Comet 17P/Holmes Observation Date: October 31, 2007

Comet 17P/Holmes Observation Date: November 2, 2007

Comet 17P/Holmes Observation Date: November 3, 2007

Comet 17P/Holmes Source: Seiichi Yoshida

Comet 17P/Holmes Measuring/Calculating Size of Coma(s) Measuring/Calculating Size of Coma(s) Width of Coma(s) in Pixels: Width of Coma(s) in Pixels: (X 2 -X 1 ) 2 + (Y 2 -Y 1 ) 2 = L 2 (X 2 -X 1 ) 2 + (Y 2 -Y 1 ) 2 = L 2 Angular Size in Pixels: Angular Size in Pixels: Pixel Resolution(") = (206,265 x Pixel Dimension)/Focal Length Pixel Resolution(") = (206,265 x Pixel Dimension)/Focal Length Angular Size(") = Pixel Resolution x L Angular Size(") = Pixel Resolution x L

Comet 17P/Holmes Angular Size  Physical Size Angular Size  Physical Size Physical Size(km) = (Angular Size x Distance from Earth)/206,265 Physical Size(km) = (Angular Size x Distance from Earth)/206,265 Physical Size→ Relative Size Physical Size→ Relative Size Relative Size(km) = Physical Size/12,756 km Relative Size(km) = Physical Size/12,756 km Date Physical Size (km) (Outer Coma) Physical Size (km) (Inner Coma) Relative Size 26-Oct233, / Oct576, , / Oct666, , / Oct766, , / Nov917, , / Nov964, , / Nov964, , /16.65

Comet 17P/Holmes Calculating Expansion Velocity Calculating Expansion Velocity V = ∆x/∆t V = ∆x/∆t DateVelocity (m/s) 10/26-10/291, /301, /30-10/ /31-11/ /02-11/ /03-11/040.00

Comet 17P/Holmes Measuring/Calculating Nuclei Separation Measuring/Calculating Nuclei Separation Separation of Nuclei in Pixels: Separation of Nuclei in Pixels: (X 2 -X 1 ) 2 + (Y 2 -Y 1 ) 2 = L 2 (X 2 -X 1 ) 2 + (Y 2 -Y 1 ) 2 = L 2 Angular Distance in Pixels: Angular Distance in Pixels: Pixel Resolution(") = (206,265 x Pixel Dimension)/Focal Length Pixel Resolution(") = (206,265 x Pixel Dimension)/Focal Length Angular Distance(") = Pixel Resolution x L Angular Distance(") = Pixel Resolution x L

Comet 17P/Holmes Angular Distance  Physical Distance Angular Distance  Physical Distance Physical Distance(km) = (Angular Distance x Distance from Earth)/206,265 Physical Distance(km) = (Angular Distance x Distance from Earth)/206,265 DatePhysical Distance (km) 26-Oct10, Oct36, Oct51, Oct55, Nov81, Nov97, Nov103,751.34

Comet 17P/Holmes Calculating Separation Velocity Calculating Separation Velocity V = ∆x/∆t V = ∆x/∆t DateVelocity (m/s) 10/26-10/ / /30-10/ /31-11/ /02-11/ /03-11/

Special Thanks to Dr. Durig Questions?