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A Comparison of Protostars in Diverse Star-Forming Environments

Kryukova, Erin
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1321652769

Abstract Details

2011, Doctor of Philosophy, University of Toledo, Physics.
Star formation occurs in a variety of environments, from massive star forming clouds like Orion, to low-mass clouds like Ophiuchus, and in more clustered and more distributed regions within clouds as well. It is not yet well understood how the environment (the density and temperature of the surrounding gas) in which a star forms a¿¿¿¿¿¿¿ects the properties i.e. mass, multiplicity, of the resulting star. This work investigates the youngest stars, which exist at or very near their birthplace, and examines the question, “How does Environment A¿¿¿¿¿¿¿ect Protostar Luminosity?” To assess this question, protostar candidates are identified in eleven tar-forming clouds, particularly clouds within 1 kpc of the sun including the relatively nearby regions of Serpens, Perseus, Ophiuchus, Chamaeleon, Lupus, Taurus, Orion, Cep OB3, and Mon R2, which combined host over 500 protostar candidates, and the massive star forming region Cygnus-X at a distance of 1.4kpc, which hosts over 2000 protostar candidates. Mid-infrared photometry from the Two-Micron All Sky Survey (2MASS) J, H, and Ks bands and Spitzer 3.6, 4.5, 5.8, 8.0, and 24 micron bands are used to identify the protostar candidates. In the nearby clouds (within 1 kpc) sources saturated at 24 micron are fit using a modified point-spread function (PSF) ¿¿¿¿¿¿¿ux extraction technique. The photometry of these sources is used to create spectral energy distributions (SEDs) from 1 - 24 microns. A new technique is developed to estimate the bolometric luminosities of protostars from their 1-24 micron photometry. Estimations of the bolometric luminosities for protostar candidates are combined to create luminosity functions for each cloud. Contamination due to edge-on disks, reddened Class II sources, and galaxies are considered and removed from luminosity functions. The luminosity functions of the clouds which form high-mass stars (Orion, Cep OB3, Mon R2, and Cygnus-X) peak near 1 Lsun and have a tail that extends to luminosities above 100 Lsun. The luminosity functions of the clouds which do not form high-mass stars do not show a common trend and many do not have significant peaks above the completeness limit. The low and high mass clouds show distinctly di¿¿¿¿¿¿¿erent protostellar luminosity functions. Luminosity functions are compared for populations of protostars in clustered and more dispersed regions within each cloud. In Orion and Cygnus-X, the two clouds with the largest samples of protostars, luminosity functions of protostars in crowded regions are significantly di¿¿¿¿¿¿¿erent from luminosity functions of protostars in more distributed regions. Additionally, the most luminous protostars in both of these clouds are in more clustered environments. The di¿¿¿¿¿¿¿erences between the luminosity functions of clustered and distributed protostar ensembles may indicate di¿¿¿¿¿¿¿erences in the emerging initial mass functions (IMFs) of the stars in these two environments.
S.T. Megeath, PhD (Advisor)
Rupali Chandar, PhD (Committee Member)
Bo Gao, PhD (Committee Member)
Lawrence Anderson-Huang, PhD (Committee Chair)
Judy Pipher, PhD (Committee Member)
137 p.
Astronomy
Star Formation; protostars; Luminosity Functions

Recommended Citations

Citations

  • Kryukova, E. (2011). A Comparison of Protostars in Diverse Star-Forming Environments [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1321652769

    APA Style (7th edition)

  • Kryukova, Erin. A Comparison of Protostars in Diverse Star-Forming Environments. 2011. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1321652769.

    MLA Style (8th edition)

  • Kryukova, Erin. "A Comparison of Protostars in Diverse Star-Forming Environments." Doctoral dissertation, University of Toledo, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1321652769

    Chicago Manual of Style (17th edition)

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© 2011, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.