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The Slow Demise Of The Long-Lived Sn 2005ip, Ori D. Fox, Claes Fransson, Nathan Smith, Jennifer Andrews, K. Azalee Bostroem, Thomas G. Brink, S. Bradley Cenko, Geoffrey C. Clayton, Alexei V. Filippenko, Wen Fai Fong, Joseph S. Gallagher, Patrick L. Kelly, Charles D. Kilpatrick, Jon C. Mauerhan, Adam M. Miller, Edward Montiel, Maximilian D. Stritzinger, Tamás Szalai, Schuyler D. Van Dyk
The Slow Demise Of The Long-Lived Sn 2005ip, Ori D. Fox, Claes Fransson, Nathan Smith, Jennifer Andrews, K. Azalee Bostroem, Thomas G. Brink, S. Bradley Cenko, Geoffrey C. Clayton, Alexei V. Filippenko, Wen Fai Fong, Joseph S. Gallagher, Patrick L. Kelly, Charles D. Kilpatrick, Jon C. Mauerhan, Adam M. Miller, Edward Montiel, Maximilian D. Stritzinger, Tamás Szalai, Schuyler D. Van Dyk
Faculty Publications
The Type IIn supernova (SN IIn) 2005ip is one of the most well-studied and long-lasting examples of an SN interacting with its circumstellar environment. The optical light curve plateaued at a nearly constant level for more than five years, suggesting ongoing shock interaction with an extended and clumpy circumstellar medium (CSM). Here, we present continued observations of the SN from ∼1000 to 5000 d post-explosion at all wavelengths, including X-ray, ultraviolet, near-infrared (NIR), and mid-infrared. The UV spectra probe the pre-explosion mass loss and show evidence for CNO processing. From the bolometric light curve, we find that the total radiated …
The Infrared View Of Dust And Molecules Around V4334 Sgr (Sakurai's Object): A 20-Yr Retrospective, A. Evans, R. D. Gehrz, C. E. Woodward, D. P.K. Banerjee, T. R. Geballe, G. C. Clayton, P. J. Sarre, S. Starrfield, K. Hinkle, R. R. Joyce, Foteini Lykou, L. A. Helton, S. P.S. Eyres, H. Worters, E. J. Montiel, T. Liimets, A. Zijlstra, M. Richter, J. Krautter
The Infrared View Of Dust And Molecules Around V4334 Sgr (Sakurai's Object): A 20-Yr Retrospective, A. Evans, R. D. Gehrz, C. E. Woodward, D. P.K. Banerjee, T. R. Geballe, G. C. Clayton, P. J. Sarre, S. Starrfield, K. Hinkle, R. R. Joyce, Foteini Lykou, L. A. Helton, S. P.S. Eyres, H. Worters, E. J. Montiel, T. Liimets, A. Zijlstra, M. Richter, J. Krautter
Faculty Publications
We present an analysis of the evolution of circumstellar dust and molecules in the environment of the very late thermal pulse object V4334 Sgr (Sakurai's object) over an ∼20-yr period, drawing on ground-, airborne-, and space-based infrared photometry and spectroscopy. The dust emission, which started in 1997, resembles a blackbody that cooled from ∼1200 K in 1998 August to ∼180 K in 2016 July. The dust mass, assuming amorphous carbon, was ∼5 × 10-10M⊙ in 1998 August, and we estimate that the total dust mass was ∼2 × 10-5M⊙ by ∼2016. The appearance of a near-infrared excess in 2008 suggests …
High-Resolution Spectroscopy Of Boyajian's Star During Optical Dimming Events, M. J. Martínez González, C. González-Fernández, A. Asensio Ramos, H. Socas-Navarro, C. Westendorp Plaza, T. S. Boyajian, J. T. Wright, A. Collier Cameron, J. I. González Hernández, G. Holgado, G. M. Kennedy, T. Masseron, E. Molinari, J. Saario, S. Simón-Díaz, B. Toledo-Padrón
High-Resolution Spectroscopy Of Boyajian's Star During Optical Dimming Events, M. J. Martínez González, C. González-Fernández, A. Asensio Ramos, H. Socas-Navarro, C. Westendorp Plaza, T. S. Boyajian, J. T. Wright, A. Collier Cameron, J. I. González Hernández, G. Holgado, G. M. Kennedy, T. Masseron, E. Molinari, J. Saario, S. Simón-Díaz, B. Toledo-Padrón
Faculty Publications
Boyajian's star is an apparently normal main-sequence F-type star with a very unusual light curve. The dipping activity of the star, discovered during the Kepler mission, presents deep, asymmetric, and aperiodic events. Here we present high-resolution spectroscopic follow-up during some dimming events recorded post-Kepler observations, from ground-based telescopes. We analyse data from the HERMES, HARPS-N, and FIES spectrographs to characterize the stellar atmosphere and to put some constraints on the hypotheses that have appeared in the literature concerning the occulting elements. The star's magnetism, if existing, is not extreme. The spots on the surface, if present, would occupy 0.02 per …
Supernova 2017eaw: Molecule And Dust Formation From Infrared Observations, Samaporn Tinyanont, Mansi M. Kasliwal, Kelsie Krafton, Ryan Lau, Jeonghee Rho, Douglas C. Leonard, Kishalay De, Jacob Jencson, Dimitri Mawet, Maxwell Millar-Blanchaer, Ricky Nilsson, Lin Yan, Robert D. Gehrz, George Helou, Schuyler D. Van Dyk, Eugene Serabyn, Ori D. Fox, Geoffrey Clayton
Supernova 2017eaw: Molecule And Dust Formation From Infrared Observations, Samaporn Tinyanont, Mansi M. Kasliwal, Kelsie Krafton, Ryan Lau, Jeonghee Rho, Douglas C. Leonard, Kishalay De, Jacob Jencson, Dimitri Mawet, Maxwell Millar-Blanchaer, Ricky Nilsson, Lin Yan, Robert D. Gehrz, George Helou, Schuyler D. Van Dyk, Eugene Serabyn, Ori D. Fox, Geoffrey Clayton
Faculty Publications
We present infrared (IR) photometry and spectroscopy of the Type II-P SN 2017eaw and its progenitor in the nearby galaxy NGC 6946. Progenitor observations in the Ks band in four epochs from 1 yr to 1 day before the explosion reveal no significant variability in the progenitor star greater than 6% that lasts longer than 200 days. SN 2017eaw is a typical SN II-P with near-IR and mid-IR photometric evolution similar to those of SNe 2002hh and 2004et, other normal SNe II-P in the same galaxy. Spectroscopic monitoring during the plateau phase reveals a possible high-velocity He i 1.083 μm …
The Double Dust Envelopes Of R Coronae Borealis Stars, Edward J. Montiel, Geoffrey C. Clayton, B. E.K. Sugerman, A. Evans, D. A. Garcia-Hernández, N. Kameswara Rao, M. Matsuura, P. Tisserand
The Double Dust Envelopes Of R Coronae Borealis Stars, Edward J. Montiel, Geoffrey C. Clayton, B. E.K. Sugerman, A. Evans, D. A. Garcia-Hernández, N. Kameswara Rao, M. Matsuura, P. Tisserand
Faculty Publications
The study of extended, cold dust envelopes surrounding R Coronae Borealis (RCB) stars began with their discovery by the Infrared Astronomical Satellite. RCB stars are carbon-rich supergiants characterized by their extreme hydrogen deficiency and their irregular and spectacular declines in brightness (up to 9 mag). We have analyzed new and archival Spitzer Space Telescope and Herschel Space Observatory data of the envelopes of seven RCB stars to examine the morphology and investigate the origin of these dusty shells. Herschel, in particular, has revealed the first-ever bow shock associated with an RCB star with its observations of SU Tauri. These data …
Extinction And The Dimming Of Kic 8462852, Huan Y.A. Meng, George Rieke, Franky Dubois, Grant Kennedy, Massimo Marengo, Michael Siegel, Kate Su, Nicolas Trueba, Mark Wyatt, Tabetha Boyajian, C. M. Lisse, Ludwig Logie, Steve Rau, Sigfried Vanaverbeke
Extinction And The Dimming Of Kic 8462852, Huan Y.A. Meng, George Rieke, Franky Dubois, Grant Kennedy, Massimo Marengo, Michael Siegel, Kate Su, Nicolas Trueba, Mark Wyatt, Tabetha Boyajian, C. M. Lisse, Ludwig Logie, Steve Rau, Sigfried Vanaverbeke
Faculty Publications
To test alternative hypotheses for the behavior of KIC 8462852, we obtained measurements of the star over a wide wavelength range from the UV to the mid-infrared from 2015 October through 2016 December, using Swift, Spitzer and AstroLAB IRIS. The star faded in a manner similar to the long-term fading seen in Kepler data about 1400 days previously. The dimming rate for the entire period reported is 22.1 ±9.7 mmag yr-1 in the Swift wavebands, with amounts of 21.0 ±4.5 mmag in the ground-based B measurements, 14.0 ±4.5 mmag in V, and 13.0 ±4.5 in R, and a rate of …
Early Dust Formation And A Massive Progenitor For Sn 2011ja?, J. E. Andrews, Kelsie M. Krafton, Geoffrey C. Clayton, E. Montiel, R. Wesson, Ben E.K. Sugerman, M. J. Barlow, M. Matsuura, H. Drass
Early Dust Formation And A Massive Progenitor For Sn 2011ja?, J. E. Andrews, Kelsie M. Krafton, Geoffrey C. Clayton, E. Montiel, R. Wesson, Ben E.K. Sugerman, M. J. Barlow, M. Matsuura, H. Drass
Faculty Publications
SN 2011ja was a bright (I=-18.3) Type II supernova occurring in the nearby edge on spiral galaxy NGC 4945. Flat-topped and multipeaked Ha and H β spectral emission lines appear between 64 and 84 d post-explosion, indicating interaction with a disc-like circumstellar medium inclined ~45° from edge-on. After day 84, an increase in the H- and K-band flux along with heavy attenuation of the red wing of the emission lines are strong indications of early dust formation, likely located in the cool dense shell created between the forward shock of the SN ejecta and the reverse shock created as the …
What Powers The 3000-Day Light Curve Of Sn 2006gy?, Ori D. Fox, Nathan Smith, S. Mark Ammons, Jennifer Andrews, K. Azalee Bostroem, S. Bradley Cenko, Geoffrey C. Clayton, Eli Dwek, Alexei V. Filippenko, Joseph S. Gallagher, Patrick L. Kelly, Jon C. Mauerhan, Adam A. Miller, Schuyler D. Van Dyk
What Powers The 3000-Day Light Curve Of Sn 2006gy?, Ori D. Fox, Nathan Smith, S. Mark Ammons, Jennifer Andrews, K. Azalee Bostroem, S. Bradley Cenko, Geoffrey C. Clayton, Eli Dwek, Alexei V. Filippenko, Joseph S. Gallagher, Patrick L. Kelly, Jon C. Mauerhan, Adam A. Miller, Schuyler D. Van Dyk
Faculty Publications
SN 2006gy was the most luminous supernova (SN) ever observed at the time of its discovery and the first of the newly defined class of superluminous supernovae (SLSNe). The extraordinary energetics of SN 2006gy and all SLSNe (>1051 erg) require either atypically large explosion energies (e.g. pair-instability explosion) or the efficient conversion of kinetic into radiative energy (e.g. shock interaction). The mass-loss characteristics can therefore offer important clues regarding the progenitor system. For the case of SN 2006gy, both a scattered and thermal light echo from circumstellar material (CSM) have been reported at later epochs (day ~800), ruling out …
What Is The Shell Around R Coronae Borealis?, Edward J. Montiel, Geoffrey C. Clayton, Dominic C. Marcello, Felix J. Lockman
What Is The Shell Around R Coronae Borealis?, Edward J. Montiel, Geoffrey C. Clayton, Dominic C. Marcello, Felix J. Lockman
Faculty Publications
The hydrogen-deficient, carbon-rich R Coronae Borealis (RCB) stars are known for being prolific producers of dust which causes their large iconic declines in brightness. Several RCB stars, including R Coronae Borealis (R CrB), itself, have large extended dust shells seen in the far-infrared. The origin of these shells is uncertain but they may give us clues to the evolution of the RCB stars. The shells could form in three possible ways. (1) They are fossil Planetary Nebula (PN) shells, which would exist if RCB stars are the result of a final, helium-shell flash, (2) they are material left over from …
Dusty Disks Around Central Stars Of Planetary Nebulae, Geoffrey C. Clayton, Orsola De Marco, Jason Nordhaus, Joel Green, Thomas Rauch, Klaus Werner, You Hua Chu
Dusty Disks Around Central Stars Of Planetary Nebulae, Geoffrey C. Clayton, Orsola De Marco, Jason Nordhaus, Joel Green, Thomas Rauch, Klaus Werner, You Hua Chu
Faculty Publications
Only a few percent of cool, old white dwarfs (WDs) have infrared excesses interpreted as originating in small hot disks due to the infall and destruction of single asteroids that come within the star's Roche limit. Infrared excesses at 24 μm were also found to derive from the immediate vicinity of younger, hot WDs, most of which are still central stars of planetary nebulae (CSPNe). The incidence of CSPNe with this excess is 18%. The Helix CSPN, with a 24 μm excess, has been suggested to have a disk formed from collisions of Kuiper belt-like objects (KBOs). In this paper, …
Kic 9406652: An Unusual Cataclysmic Variable In The Kepler Field Of View, Douglas R. Gies, Zhao Guo, Steve B. Howell, Martin D. Still, Tabetha S. Boyajian, Abe J. Hoekstra, Kian J. Jek, Daryll Lacourse, Troy Winarski
Kic 9406652: An Unusual Cataclysmic Variable In The Kepler Field Of View, Douglas R. Gies, Zhao Guo, Steve B. Howell, Martin D. Still, Tabetha S. Boyajian, Abe J. Hoekstra, Kian J. Jek, Daryll Lacourse, Troy Winarski
Faculty Publications
KIC 9406652 is a remarkable variable star in the Kepler field of view that shows both very rapid oscillations and long term outbursts in its light curve. We present an analysis of the light curve over quarters 1-15 and new spectroscopy that indicates that the object is a cataclysmic variable with an orbital period of 6.108 hr. However, an even stronger signal appears in the light curve periodogram for a shorter period of 5.753 hr, and we argue that this corresponds to the modulation of flux from the hot spot region in a tilted, precessing disk surrounding the white dwarf …
Evolution Of The 1919 Ejecta Of V605 Aquilae, Geoffrey C. Clayton, Howard E. Bond, Lindsey A. Long, Paul I. Meyer, Ben E.K. Sugerman, Edward Montiel, William B. Sparks, M. G. Meakes, O. Chesneau, O. De Marco
Evolution Of The 1919 Ejecta Of V605 Aquilae, Geoffrey C. Clayton, Howard E. Bond, Lindsey A. Long, Paul I. Meyer, Ben E.K. Sugerman, Edward Montiel, William B. Sparks, M. G. Meakes, O. Chesneau, O. De Marco
Faculty Publications
New imaging of V605 Aql, was obtained in 2009 with HST/WFPC2, which had a nova-like outburst in 1919, and is located at the center of the planetary nebula (PN), A58. This event has long been ascribed to a final helium shell flash, but it has been suggested recently that it may instead have been an ONe nova. The new images provide an 18 yr baseline for the expansion of the ejecta from the 1919 event. In addition, the central star has been directly detected in the visible for the first time since 1923, when it faded from sight due to …
Optical And Infrared Analysis Of Type Ii Sn 2006bc, Joseph S. Gallagher, B. E.K. Sugerman, Geoffrey C. Clayton, J. E. Andrews, J. Clem, M. J. Barlow, B. Ercolano, J. Fabbri, M. Otsuka, R. Wesson, M. Meixner
Optical And Infrared Analysis Of Type Ii Sn 2006bc, Joseph S. Gallagher, B. E.K. Sugerman, Geoffrey C. Clayton, J. E. Andrews, J. Clem, M. J. Barlow, B. Ercolano, J. Fabbri, M. Otsuka, R. Wesson, M. Meixner
Faculty Publications
We present nebular phase optical imaging and spectroscopy and near/mid-IR imaging of the Type II SN 2006bc. Observations reveal the central wavelength of the symmetric Hα line profile to be redshifted with respect to the host galaxy Hα emission by day 325. Such a phenomenon has been argued to result from an asymmetric explosion in the iron-peak elements resulting in a larger mass of 56Ni and higher excitation of hydrogen on the far side of the supernova (SN) explosion. We also observe a gradual blueshifting of this Hα peak which is indicative of dust formation in the ejecta. Although showing …
Thirty Years Of Sn 1980k: Evidence For Light Echoes, Ben E.K. Sugerman, Jennifer E. Andrews, Michael J. Barlow, Geoffrey C. Clayton, Barbara Ercolano, Parviz Ghavamian, Robert C. Kennicutt, Oliver Krause, Margaret Meixner, Masaaki Otsuka
Thirty Years Of Sn 1980k: Evidence For Light Echoes, Ben E.K. Sugerman, Jennifer E. Andrews, Michael J. Barlow, Geoffrey C. Clayton, Barbara Ercolano, Parviz Ghavamian, Robert C. Kennicutt, Oliver Krause, Margaret Meixner, Masaaki Otsuka
Faculty Publications
We report optical and mid-infrared photometry of SN 1980K between 2004 and 2010, which shows slow monotonic fading consistent with previous spectroscopic and photometric observations made 8-17yr after outburst. The slow rate of change over two decades suggests that this evolution may result from scattered and thermal light echoes off of extended circumstellar material. We present a semi-analytic dust radiative-transfer model that uses an empirically corrected effective optical depth to provide a fast and robust alternative to full Monte Carlo radiative-transfer modeling for homogenous dust at low to intermediate optical depths. We find that unresolved echoes from a thin circumstellar …
The Effects Of Dust On The Optical And Infrared Evolution Of Sn 2004et, J. Fabbri, M. Otsuka, M. J. Barlow, Joseph S. Gallagher, R. Wesson, B. E.K. Sugerman, Geoffrey C. Clayton, M. Meixner, J. E. Andrews, D. L. Welch, B. Ercolano
The Effects Of Dust On The Optical And Infrared Evolution Of Sn 2004et, J. Fabbri, M. Otsuka, M. J. Barlow, Joseph S. Gallagher, R. Wesson, B. E.K. Sugerman, Geoffrey C. Clayton, M. Meixner, J. E. Andrews, D. L. Welch, B. Ercolano
Faculty Publications
We present an analysis of multi-epoch observations of the Type II-P supernova SN 2004et. New and archival optical spectra of SN 2004et are used to study the evolution of the Hα and [Oi] 6300-Å line profiles between days 259 and 646. Mid-infrared imaging with Michelle on Gemini-North and with all three instruments of the Spitzer Space Telescope was carried out between 2004 and 2010, supplemented by archival Spitzer data. We include Spitzer'warm' mission photometry at 3.6 and 4.5μm obtained on days 1779, 1931 and 2151, along with ground-based and Hubble Space Telescope (HST) optical and near-infrared observations obtained between days …
Spectroscopic Hα And Hγ Survey Of Field Be Stars: 2004-2009, Erika D. Grundstrom, Douglas R. Gies, Christina Aragona, Tabetha S. Boyajian, E. Victor Garcia, Amber N. Marsh, M. Virginia Mcswain, Rachael M. Roettenbacher, Stephen J. Williams, David W. Wingert
Spectroscopic Hα And Hγ Survey Of Field Be Stars: 2004-2009, Erika D. Grundstrom, Douglas R. Gies, Christina Aragona, Tabetha S. Boyajian, E. Victor Garcia, Amber N. Marsh, M. Virginia Mcswain, Rachael M. Roettenbacher, Stephen J. Williams, David W. Wingert
Faculty Publications
Massive O- and B-type stars are "cosmic engines" in the Universe and can be the dominant source of luminosity in a galaxy. The class of Be stars are rapidly rotating B-type stars that lose mass in an equatorial, circumstellar disk (Porter & Rivinius 2003) and cause Balmer and other line emission. Currently, we are unsure as to why these stars rotate so quickly but three scenarios are possible: they may have been born as rapid rotators, spun up by binary mass transfer, or spun up during the main-sequence evolution of B stars. In order to investigate these scenarios for this …
The 2011 Outburst Of The Recurrent Nova T Pyxidis. Evidence For A Face-On Bipolar Ejection, O. Chesneau, A. Meilland, D. P.K. Banerjee, J. B. Le Bouquin, H. Mcalister, F. Millour, S. T. Ridgway, A. Spang, T. Ten Brummelaar, M. Wittkowski, N. M. Ashok, M. Benisty, J. P. Berger, T. Boyajian, Ch Farrington, P. J. Goldfinger, A. Merand, N. Nardetto, R. Petrov, Th Rivinius, G. Schaefer, Y. Touhami, G. Zins
The 2011 Outburst Of The Recurrent Nova T Pyxidis. Evidence For A Face-On Bipolar Ejection, O. Chesneau, A. Meilland, D. P.K. Banerjee, J. B. Le Bouquin, H. Mcalister, F. Millour, S. T. Ridgway, A. Spang, T. Ten Brummelaar, M. Wittkowski, N. M. Ashok, M. Benisty, J. P. Berger, T. Boyajian, Ch Farrington, P. J. Goldfinger, A. Merand, N. Nardetto, R. Petrov, Th Rivinius, G. Schaefer, Y. Touhami, G. Zins
Faculty Publications
Aims.T Pyx is the first recurrent nova ever historically studied. It was seen in outburst six times between 1890 and 1966 and then not for 45 years. We report on near-IR interferometric observations of the recent outburst of 2011. Methods.We obtained near-IR observations of T Pyx at dates ranging from t = 2.37 d to t = 48.2 d after the outburst, with the CLASSIC recombiner located at the CHARA array and with the PIONIER and AMBER recombiners located at the VLTI array. These data are supplemented with near-IR photometry and spectra obtained at Mount Abu, India. We compare expansion …
Herschel Observations Of A Newly Discovered Ux Ori Star In The Large Magellanic Cloud, Geoffrey C. Clayton, B. Sargent, M. L. Boyer, B. A. Whitney, Jacco Th Van Loon, M. Meixner, P. Tisserand, C. Engelbracht, S. Hony, R. Indebetouw, K. A. Misselt, K. Okumura, P. Panuzzo, J. Roman-Duval, M. Sauvage, J. M. Oliveira, M. Sewiło, E. Churchwell
Herschel Observations Of A Newly Discovered Ux Ori Star In The Large Magellanic Cloud, Geoffrey C. Clayton, B. Sargent, M. L. Boyer, B. A. Whitney, Jacco Th Van Loon, M. Meixner, P. Tisserand, C. Engelbracht, S. Hony, R. Indebetouw, K. A. Misselt, K. Okumura, P. Panuzzo, J. Roman-Duval, M. Sauvage, J. M. Oliveira, M. Sewiło, E. Churchwell
Faculty Publications
The LMC star, SSTISAGE1C J050756.44-703453.9, was first noticed during a survey of EROS-2 light curves for stars with large irregular brightness variations typical of the R Coronae Borealis (RCB) class. However, the visible spectrum showing emission lines including the Balmer and Paschen series as well as many Fe ii lines is emphatically not that of an RCB star. This star has all of the characteristics of a typical UX Ori star. It has a spectral type of approximately A2 and has excited an Hii region in its vicinity. However, if it is an LMC member, then it is very luminous …
Cold Dust In Three Massive Evolved Stars In The Lmc, M. L. Boyer, B. Sargent, J. Th Van Loon, S. Srinivasan, G. C. Clayton, F. Kemper, L. J. Smith, M. Matsuura, Paul M. Woods, M. Marengo, M. Meixner, C. Engelbracht, K. D. Gordon, S. Hony, R. Indebetouw, K. Misselt, K. Okumura, P. Panuzzo, D. Riebel, J. Roman-Duval, M. Sauvage, G. C. Sloan
Cold Dust In Three Massive Evolved Stars In The Lmc, M. L. Boyer, B. Sargent, J. Th Van Loon, S. Srinivasan, G. C. Clayton, F. Kemper, L. J. Smith, M. Matsuura, Paul M. Woods, M. Marengo, M. Meixner, C. Engelbracht, K. D. Gordon, S. Hony, R. Indebetouw, K. Misselt, K. Okumura, P. Panuzzo, D. Riebel, J. Roman-Duval, M. Sauvage, G. C. Sloan
Faculty Publications
Massive evolved stars can produce large amounts of dust, and far-infrared (IR) data are essential for determining the contribution of cold dust to the total dust mass. Using Herschel, we search for cold dust in three very dusty massive evolved stars in the Large Magellanic Cloud: R71 is a luminous blue variable, HD 36402 is a Wolf-Rayet triple system, and IRAS05280-6910 is a red supergiant. We model the spectral energy distributions using radiative transfer codes and find that these three stars have mass-loss rates up to 10-3 Modot; yr-1, suggesting that high-mass stars are important contributors to the life-cycle of …
The Destruction And Survival Of Dust In The Shell Around Sn 2008s, R. Wesson, M. J. Barlow, B. Ercolano, J. E. Andrews, Geoffrey C. Clayton, J. Fabbri, Joseph S. Gallagher, M. Meixner, B. E.K. Sugerman, D. L. Welch, D. J. Stock
The Destruction And Survival Of Dust In The Shell Around Sn 2008s, R. Wesson, M. J. Barlow, B. Ercolano, J. E. Andrews, Geoffrey C. Clayton, J. Fabbri, Joseph S. Gallagher, M. Meixner, B. E.K. Sugerman, D. L. Welch, D. J. Stock
Faculty Publications
SN 2008S erupted in early 2008 in the grand design spiral galaxy NGC 6946. The progenitor was detected by Prieto et al. in Spitzer Space Telescope images taken over the four years prior to the explosion, but was not detected in deep optical images, from which they inferred a self-obscured object with a mass of about 10 M⊙. We obtained Spitzer observations of SN MTSY.-1.circledot 2008S 5 days after its discovery, as well as coordinated Gemini and Spitzer optical and infrared observations 6 months after its outburst. We have constructed radiative transfer dust models for the object before and after …
Sn 2007od: A Type Iip Supernova With Circumstellar Interaction, J. E. Andrews, J. S. Gallagher, Geoffrey C. Clayton, B. E.K. Sugerman, J. P. Chatelain, J. Clem, D. L. Welch, M. J. Barlow, B. Ercolano, J. Fabbri, R. Wesson, M. Meixner
Sn 2007od: A Type Iip Supernova With Circumstellar Interaction, J. E. Andrews, J. S. Gallagher, Geoffrey C. Clayton, B. E.K. Sugerman, J. P. Chatelain, J. Clem, D. L. Welch, M. J. Barlow, B. Ercolano, J. Fabbri, R. Wesson, M. Meixner
Faculty Publications
SN 2007od exhibits characteristics that have rarely been seen in a Type IIP supernova (SN). Optical V-band photometry reveals a very steep brightness decline between the plateau and nebular phases of 4.5mag, likely due to SN 2007od containing a low mass of 56Ni. The optical spectra show an evolution from normal Type IIP with broad Hα emission, to a complex, four-component Hα emission profile exhibiting asymmetries caused by dust extinction after day 232. This is similar to the spectral evolution of the Type IIn SN 1998S, although no early-time narrow (200kms-1) Hα component was present in SN 2007od. In both …
Dust Around Red Supergiants In The Magellanic Clouds, Geoffrey C. Clayton, W. Freeman, S. Bright, P. Massey, K. D. Gordon, E. Levesque, B. Plez, K. Olsen, J. Nordhaus
Dust Around Red Supergiants In The Magellanic Clouds, Geoffrey C. Clayton, W. Freeman, S. Bright, P. Massey, K. D. Gordon, E. Levesque, B. Plez, K. Olsen, J. Nordhaus
Faculty Publications
It is both surprising and exciting to find that young galaxies at high redshift contain large dust masses. For galaxies at z > 5, after only 1 Gyr, there has not been time for low-mass stars to have evolved to the AGB phase and produce dust. In such galaxies, Type II SNe and red supergiants (RSGs) may even dominate the dust production rate. It has long been known that RSG atmospheres produce dust, but little is known about it. We are pursuing three parallel studies to better understand RSG dust. First, we are using optical spectra and JHK photometry to characterize …
Long-Term Optical/Infrared Variability In The Quiescent X-Ray Transient V404 Cyg, C. Zurita, J. Casares, R. I. Hynes, T. Shahbaz, P. A. Charles, E. P. Pavlenko
Long-Term Optical/Infrared Variability In The Quiescent X-Ray Transient V404 Cyg, C. Zurita, J. Casares, R. I. Hynes, T. Shahbaz, P. A. Charles, E. P. Pavlenko
Faculty Publications
We present the results of optical and infrared photometry of the quiescent X-ray transient V404 Cyg during the period 1992-2003. The ellipsoidal modulations extracted from the most complete data bases (years 1992, 1998 and 2001) show unequal maxima and minima with relative strength varying from year to year although their peak-to-peak amplitudes remain roughly constant at 0.24 ± 0.01 mag. Fast optical variations superimposed on the double-humped ellipsoidal modulation of the secondary star were detected every year with a mean amplitude of ∼0.07 mag. We have not found significant changes in the activity during this decade which indicates that this …
Dust Formation Above Cool Magnetic Spots In Evolved Stars, Noam Soker, Geoffrey C. Clayton
Dust Formation Above Cool Magnetic Spots In Evolved Stars, Noam Soker, Geoffrey C. Clayton
Faculty Publications
We examine the structure of cool magnetic spots in the photospheres of evolved stars, specifically asymptotic giant branch (AGB) stars and R Coronae Borealis (RCB) stars. We find that the photosphere of a cool magnetic spot will be above the surrounding photosphere of AGB stars, which is the opposite of the situation in the Sun. This results from the behaviour of the opacity, which increases with decreasing temperature, which again is the opposite of the behaviour of the opacity near the effective temperature of the Sun. We analyse the formation of dust above the cool magnetic spots, and suggest that …