Criteria for Candidates

1. Introduction Planetary nebulae are crucial in returning heavier metals into the interstellar medium, influencing later star and galaxy formation (Aller & Keyes, 87). Criteria for Candidates Altitude > 40°; Apparent Magnitude > 14; Available Distance and Angular Radius; Available Spectra Knowledge Base + Figure 1: Probable chemical composition for planetary nebula. H-R Diagram depicts where planetary nebulae are in spectral class. Figure Three: Chart is a template that was used to determine spectral lines. Figure Four: This chart shows the ionization potentials for each element. • Literature Review • -Czyszka et. al (2009) NGC 6302, found ionization potentials, then used to find the temperature of the central star. This was then plotted on the H-R Diagram. • Copetti (2000) found comparison among electron density estimates for PNe based on different emission line ratios. The electron density needed to characterize planetary nebulae in order to derive chemical abundances, calculate the mass of the total ionized gas and to estimate the distance of the object. • Harrington (1969) ionization stratification and chemical abundances in the planetary nebula NGC 7662 (candidate chosen in this study itself). Distance calculated by measuring the rate of angular expansion in correspondence to the gas velocity. • Arnold (2008) suggested of the structure of PNe. Hot stars provide UV photons, and a typical nebula spectrum will have very little continuum, producing much of its flux in various emission lines Figure 5 Stratification of ions: higher near core, lower farther from star Arnold, Jacob (2008) Purpose To find a correlation between mass and ionization potentials as well as to see if mass affects elements expelled into interstellar medium and relate to age and density. Project Goals -Identify emission lines -Identify ionization potentials -Determine Density, Volume and Mass

2. 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 • Limitations • Possible discrepancies in identification of emission lines • 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 Bibliography Aller & Keyes, et al. “A Spectroscopic Survey of 51 Planetary Nebulae.” 19871. Arnold, Jacob. “Planetary Nebulae. AY 230, Fall 2008. Canright, Shelley. “Stellar Evolution - The Birth, Life, and Death of a Star.” NASA. 10 April 2009. <http://www.nasa.gov/ audience/forstudents/912/features/stellar_evol_feat_912.html> Ciardullo, Robin. “The Planetary Nebula Luminosity Function.” Astrophysical Journal. 14 July 2004. Covington, Michael A. “Processing DSLR Raw Images with MaxDSLR and MaxIm DL.” 25 December 2006. http://www.covingtoninnovations.com/dslr/MaxDSLR/index.html#top Guerrero, Martin A. “Physical Structure of Planetary Nebulae. II. NGC 7662.” The Astronomical Journal, American Astronomical Society. October 2004. Flower, D.R. “The Ionization Structure of Planetary Nebulae-VII:The Heavy Elements.” Royal Astronomical Society, Vol. 146, pg 171. 24 July 1969. Herrmann, Kimberly A. “Planetary Nebulae in Face-On Spiral Galaxies. II. Planetary Nebula Spectroscopy.” Astrophysical Journal. 4 August 2009. Jacoby, George et al. “A Library of Stellar Spectra.” Astrophysical Journal. October 1984. Kelusa, Craig. “What is Spectroscopy?” University of Arizona. 14 Feb 1997. <http://loke.as.arizona.edu/~ckulesa/camp/spectroscopy_intro.html> Kwitter, Karen B. “Gallery of Planetary Nebulae Spectra.” Williams College.<http://oit.williams.edu/nebulae/Exercise1.html> 2006. Lee, Kevin. “Spectral Classification of Stars.” 2005. <http://astro.unl.edu/naap/hr/hr_background1.html> Lestition, Kathy. “Stellar Evolution.” Chandra X-Ray Observatory. NASA. 24 September 2008. <http://chandra.harvard.edu/edu/formal/stellar_ev/> National Optical Astronomy Observatory. “Spectral Analysis for the RV Tau Star R Sct.”RBSE. 2008. Ransom, R. R. et al. “Probing the Magnetized Interstellar Medium Surrounding the Planetary Nebula SH 2-216.” AstrophysicalJournal. 9 June 2008. Sabbadin, F. “Planetary Nebulae at Known Distance.” Astronomy and Astrophysics Supplement Series Vol. 64, No. 3. June 1986. Sandin, Christopher et. al. “Spatially Resolved Spectroscopy of Planetary Nebulae and their Halos.” Astronomy & Astrophysics Institute Potsdam, Germany. 4 July 2008. Santa Barbara Instrument Group. “DSS-7: Deep Space Spectrograph.” 20 March 2006. <http://www.sbig.com/sbwhtmls/online.htm> Seeds, Michael A. Foundations of Astronomy. Brooks/Cole. 2005. Sloan Digital Sky Survey. “The Hertzsprung-Russell Diagram.” 2007.<http://cas.sdss.org/dr7/en/proj/advanced/hr/> Stanghellini, Letizie. “The Magellanic Cloud Calibration of the Galactic Planetary Nebula Scale.” Astrophysical Journal. 7 July 2008. Szyszka C. et al. “Detection of the Central Star of the Planetary Nebula NGC 6302.” Astrophysical Journal. 21 October 2009. Webster, Louise B. “The Masses and Galactic Distribution of Southern Planetary Nebulae.” Royal Astronomical Society. 11 April 1968.