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Clues to the Evolution of R Coronae Borealis Stars

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Clues to the Evolution of R Coronae Borealis Stars Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 2016 Circumstellar Dust Shells: Clues to the Evolution of R Coronae Borealis Stars Edward Joseph Montiel Louisiana State University and Agricultural and Mechanical College, [email protected] Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_dissertations Part of the Physical Sciences and Mathematics Commons Recommended Citation Montiel, Edward Joseph, "Circumstellar Dust Shells: Clues to the Evolution of R Coronae Borealis Stars" (2016). LSU Doctoral Dissertations. 3683. https://digitalcommons.lsu.edu/gradschool_dissertations/3683 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Doctoral Dissertations by an authorized graduate school editor of LSU Digital Commons. For more information, please [email protected]. CIRCUMSTELLAR DUST SHELLS: CLUES TO THE EVOLUTION OF R CORONAE BOREALIS STARS A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Physics and Astronomy by Edward Joseph Montiel B.S., The University of Arizona, 2010 M.S., Louisiana State University, 2015 August 2016 For Lynne, Ida, and Michael ii Acknowledgements \If I have seen further it is by standing on the shoulders of giant" is an expression that Isaac Newton used in a letter to Robert Hooke to describe how his successes were only possible due to the previous work of others. I have also been extremely fortunate to stand on the shoulders of some incredible giants during the pursuit of my Ph.D. I would like to start by thanking my mother, Lynne Montiel, Bubby, Ida Weintraub, and younger brother, Michael Montiel. Their combined love and support have carried me throughout this entire process. I would also like to thank, on an equal level, my advisor, Geoffrey Clayton. There is no way that I would be finishing in four years without your incomparable skill to rein me in whenever I started to stray too far from or too long on any one task. I want to thank Jarita Holbrook for all of the mentorship she has provided me ever since I showed up at her office in Tucson as a wide{eyed freshman. To Jay Lockman, thank you for being so patient in teaching me how to be a radio astronomer. To the other members of the RCB community: Tom Geballe, Warrick Lawson, Patrick Tisserand, and Doug Welch, thank you for all of the feedback and encouragement you have provided. I would like to acknowledge all of the exceptional research mentors I have had the privilege of working with over my very short career: Gina Brissenden, Heather Morrison, Paul Smith, Kenneth Mighell, Charles Engelbracht, Joannah Hinz, Karl Misselt, Kate Su, and Margaret Meixner. I'm forever indebted that you took a chance on working with me, for making me a better astronomer and person, and for continuing to support me in the form of countless letters of recommendations. Further, I would like to say to Charles Engelbracht, who passed away much too soon, that I miss you everyday. I would also like to thank the numerous friends that I have made over the years. You are simply too many to list and I hope that you will not take any omission as a slight. To Chris Johnson, thank you for being the best \comrade{in{arms", from the start of graduate school to the finish it has been a great adventure. To every- one that made my stay in Louisiana one of the best experiences of my life: Alison Dreyfuss, Robert Baker, Jon Brown, Robin Cobb, Jon Cripe, Elissa DeLoach, Zach Edwards, Aaron Grocholski, Brittany Fortmayer, Anton Joe, Kundan Kadam, Mar- ianne Konikoff, Kelsie Krafton, Amber Lauer, Amy LeBleu, Ishita Maity, Dominic Marcello, Ischelle Martin, Noah Morris, Kat Munley, Jonny Olson, D. J. Pleshinger, Alison Schreckengast, Paige Thibodeaux, Zhichao Xue, Julia Yarbrough. To Rachelle Baker, Sean Cronin, Jeremy Disque, Jason Dittmann, Shannon Macke, Colin Meyers, Drew Milsom, Rita Morris, Leigh Moyer, Trevor Olson, Jesse Ross, Chris Stanley, Sarah Wiersma, Chris Wittoesch thank you likewise for all of the wonderful experi- ences in Tucson and beyond. iii Table of Contents Acknowledgements . iii List of Tables . vi List of Figures . vii Abstract . ix 1. Introduction . 1 1.1 R Coronae Borealis Variables . 1 1.2 Single vs. Double Degenerate Origins . 2 1.2.1 Stellar Mass & Multiplicity . 3 1.2.2 Elemental Abundances . 5 1.2.3 Diffuse Dust Shells . 6 1.3 Goals . 8 2. Observations and Analysis . 9 2.1 Observations . 9 2.1.1 Ultraviolet Data . 10 2.1.2 Optical Monitoring . 13 2.1.3 Near Infrared Monitoring . 14 2.1.4 Two Micron All Sky Survey . 14 2.1.5 Infrared Space Observatory . 14 2.1.6 Spitzer Space Telescope . 15 2.1.7 Wide-field Infrared Survey Explorer . 15 2.1.8 AKARI . 15 2.1.9 Infrared Astronomical Satellite . 16 2.1.10 Herschel Space Observatory . 16 2.1.11 Radio . 17 2.2 Spectral Energy Distribution Modeling . 17 2.2.1 Photometry . 17 2.2.2 MOCASSIN . 20 3. What is the Shell Around R Coronae Borealis? . 23 3.1 Origin of the R CrB Dust Shell . 23 3.1.1 The R CrB Dust Shell . 23 3.1.2 A Planetary Nebula Shell? . 23 iv 3.1.3 Mass Loss from a White Dwarf Merger? . 26 3.1.4 RCB Phase Mass Loss? . 27 3.2 Chapter Summary . 28 4. The Circumstellar Shells of R Coronae Borealis Stars . 29 4.1 MV Sgr . 29 4.1.1 Image Inspection . 29 4.1.2 Radiative Transfer Modeling . 30 4.2 R CrB . 33 4.2.1 Image Inspection . 33 4.2.2 Radiative Transfer Modeling . 35 4.3 RY Sgr . 38 4.3.1 Image Inspection . 38 4.3.2 Radiative Transfer Modeling . 41 4.4 SU Tau . 44 4.4.1 Image Inspection . 44 4.4.2 Radiative Transfer Modeling . 48 4.5 UW Cen . 51 4.5.1 Image Inspection . 51 4.5.2 Radiative Transfer Modeling . 52 4.6 V854 Cen . 55 4.6.1 Image Inspection . 55 4.6.2 Radiative Transfer Modeling . 56 4.7 V CrA . 59 4.7.1 Image Inspection . 59 4.7.2 Radiative Transfer Modeling . 61 4.8 Sample Properties . 63 4.8.1 CSM Morphology . 63 4.8.2 Envelope Masses & Decline Activity . 66 4.8.3 Comparison to an HdC Star & FF Object . 68 4.9 MCRT Model Summary . 74 5. Discussion & Conclusions . 76 Bibliography . 81 Appendix. Permission to Reproduce Copyrighted Material . 90 A.1 Copyright Agreement with AAS . 90 A.2 Permission to use Figure 1.2 . 90 A.3 Permission to use Figure 1.3 . 91 A.4 Permission to use Figure 1.4 . 91 A.5 Permission to use Figure 1.5 . 91 A.6 Permission to use Figure 4.20 . 92 Vita . 93 v List of Tables 2.1 Stellar Properties and New Observations of Sample RCB Stars . 9 3.1 Model Results . 27 3.2 Shell Types . 27 4.1 MV Sgr Photometry . 31 4.2 R CrB Photometry . 36 4.3 RY Sgr Photometry . 42 4.4 SU Tau Photometry . 49 4.5 UW Cen Photometry . 53 4.6 V854 Cen Photometry . 57 4.7 V CrA Photometry . 62 4.8 V605 Aql Photometry . 69 4.9 HD 173409 Photometry . 72 5.1 Derived MOCASSIN Properties and Measured Outer Radii . 78 vi List of Figures 1.1 AAVSO Lightcurve of UW Cen from 1975 to 2005 . 2 1.2 RCB Mass Determination via Pulsation Analysis . 4 1.3 NIR Spectra of RCB stars showing 18O................. 5 1.4 Optical Spectra of RCB stars showing 19F ............... 6 1.5 IRAS 100 µm Contour Map of the R CrB Shell . 7 2.1 AAVSO Light Curves of R CrB & RY Sgr . 10 2.2 AAVSO Light curves of SU Tau & UW Cen . 11 2.3 AAVSO Light Curves of V854 Cen & V CrA . 12 2.4 AAVSO Light Curve of MV Sgr . 13 2.5 Cartoon of Aperture Photometry . 18 2.6 Spitzer=MIPS PSFs . 19 2.7 Herschel=PACS PSFs . 19 2.8 Herschel=SPIRE PSFs . 20 2.9 MOCASSIN Dust Grid Accounting for Spherical Symmetry . 21 2.10 MOCASSIN Dust Grid for a Full Sphere . 22 3.1 L{band Observation of the Field containing R CrB . 24 3.2 Background{Subtracted Temperature vs. HI Velocity of Field around RCrB................................... 25 4.1 Spitzer Observations of MV Sgr . ..
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