+

Criteria for CandidatesAltitude > 40°; Apparent Magnitude

> 14; Available Distance and Angular Radius; Available Spectra

IntroductionPlanetary nebulae are crucial in

returning heavier metals into the interstellar medium, influencing later star and galaxy formation

(Aller & Keyes, 87).

Project Goals-Identify emission lines

-Identify ionization potentials-Determine Density, Volume and Mass

Purpose To find a correlation between mass and ionization potentials as well as to see if mass affects elements expelled into interstellar

medium

Pictures of Candidates and Spectra from Williams (from top) NGC 7662; IC 1747; IC 289; M1-4; M2-2; NGC

7008; NGC 7534

Chart is a template that was used to determine spectral lines.

Probable chemical composition for planetary nebula.

Knowledge Base

Literature Review-C. Szyka, JR Walsh et al determined

the highest ionization potential of planetary nebula NGC 6302 by use of

spectral analysis. They also calculated temperature.

- K. Hermann et al determined the mass of several planetary nebulae

and found distance using the luminosity function.

- B Webster studied emissions of magellanic clouds as determined

approximated distances.

Figure 1 Stratification of ions: higher near core, lower farther from star

Arnold, Jacob (2008)

Results• Spectra reveal lighter chemical elements

Most massive overall- Ar• Significant direct correlation found between mass and highest ionization potential value, r=0.944 and p=0.01 (Graph 1)• Age (youngest to oldest) vs. average density: significant direct inverse relationship, younger nebulae are more dense than older, r=-0.926 and p=0.037 (Graph 2)

Discussion• Goals: identify element, calculate ionization potentials/mass, find correlation, relate to age and evolution• supports findings of Harrington (1969), Szyszka et. al (2009)• Direct correlation: more massive PN, greater value of highest ionization potential• Chemicals returned to interstellar medium lighter

PNe and central stars same composition Future star formation- same present elements

• Relative ages determined: heavier elements found in older PNe due to nuclear fusion over time

Grouped and compared to average density, inverse relationship found- older nebulae have lower densities due to less massive chemicals present and ionized

Conclusion• Mass and highest ionization potentials have correlation: greater mass related to larger ionization potential values• Less massive chemicals returned to interstellar medium and compose central stars and PNe• PNe relatively old in age

only light elements present, nuclear fusion did not create heavier elements yet

older PNe, less dense• Predict stellar evolution

Future Studies• Harrington (1969)- temperature and luminosities calculated from ionization potentials, help place nebulae along H-R diagram• Relation to mass, density, age

Limitations• Possible discrepancies in identification of emission lines

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