168 results on '"Howard, E"'
Search Results
2. The Orbit and Dynamical Mass of Polaris: Observations with the CHARA Array
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Nancy Remage Evans, Gail H. Schaefer, Alexandre Gallenne, Guillermo Torres, Elliott P. Horch, Richard I. Anderson, John D. Monnier, Rachael M. Roettenbacher, Fabien Baron, Narsireddy Anugu, James W. Davidson Jr., Pierre Kervella, Garance Bras, Charles Proffitt, Antoine Mérand, Margarita Karovska, Jeremy Jones, Cyprien Lanthermann, Stefan Kraus, Isabelle Codron, Howard E. Bond, and Giordano Viviani
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Cepheid variable stars ,Stellar masses ,Astrophysics ,QB460-466 - Abstract
The 30 yr orbit of the Cepheid Polaris has been followed with observations by the Center for High Angular Resolution Astronomy (CHARA) Array from 2016 through 2021. An additional measurement has been made with speckle interferometry at the Apache Point Observatory. Detection of the companion is complicated by its comparative faintness—an extreme flux ratio. Angular diameter measurements appear to show some variation with pulsation phase. Astrometric positions of the companion were measured with a custom grid-based model-fitting procedure and confirmed with the CANDID software. These positions were combined with the extensive radial velocities (RVs) discussed by Torres to fit an orbit. Because of the imbalance of the sizes of the astrometry and RV data sets, several methods of weighting are discussed. The resulting mass of the Cepheid is 5.13 ± 0.28 M _⊙ . Because of the comparatively large eccentricity of the orbit (0.63), the mass derived is sensitive to the value found for the eccentricity. The mass combined with the distance shows that the Cepheid is more luminous than predicted for this mass from evolutionary tracks. The identification of surface spots is discussed. This would give credence to the identification of a radial velocity variation with a period of approximately 120 days as a rotation period. Polaris has some unusual properties (rapid period change, a phase jump, variable amplitude, and unusual polarization). However, a pulsation scenario involving pulsation mode, orbital periastron passage, and low pulsation amplitude can explain these characteristics within the framework of pulsation seen in Cepheids.
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- 2024
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3. Spectroscopic Survey of Faint Planetary-nebula Nuclei. V. The EGB 6-type Central Star of Abell 57
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Howard E. Bond, Akshat S. Chaturvedi, Robin Ciardullo, Klaus Werner, Gregory R. Zeimann, and Michael H. Siegel
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Planetary nebulae nuclei ,Planetary nebulae ,White dwarf stars ,Infrared sources ,Circumstellar dust ,Post-asymptotic giant branch stars ,Astrophysics ,QB460-466 - Abstract
During our spectroscopic survey of central stars of faint planetary nebulae (PNe), we found that the nucleus of Abell 57 exhibits strong nebular emission lines. Using synthetic narrowband images, we show that the emission arises from an unresolved compact emission knot (CEK) coinciding with the hot (90,000 K) central star. Thus Abell 57 belongs to the rare class of “EGB 6-type” PNe, characterized by dense emission cores. Photometric data show that the nucleus exhibits a near-infrared excess, due to a dusty companion body with the luminosity of an M0 dwarf but a temperature of ∼1800 K. Emission-line analysis reveals that the CEK is remarkably dense (electron density ∼ 1.6 × 10 ^7 cm ^−3 ), and has a radius of only ∼4.5 au. The CEK suffers considerably more reddening than the central star, which itself is more reddened than the surrounding PN. These puzzles may suggest an interaction between the knot and central star; however, Hubble Space Telescope imaging of EGB 6 itself shows that its CEK lies more than ∼125 au from the PN nucleus. We discuss a scenario in which a portion of the asymptotic giant branch wind that created the PN was captured into a dust cloud around a distant stellar companion; this cloud has survived to the present epoch, and has an atmosphere photoionized by radiation from the hot central star. However, in this picture EGB 6-type nuclei should be relatively common, yet they are actually extremely rare; thus they may arise from a different transitory phenomenon. We suggest future observations of Abell 57 that may help unravel its mysteries.
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- 2024
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4. Erratum: 'Hubble Space Telescope Snapshot Survey for Resolved Companions of Galactic Cepheids: Final Results' (2020, ApJ, 905, 81)
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Nancy Remage Evans, H. Moritz Günther, Howard E. Bond, Gail H. Schaefer, Brian D. Mason, Margarita Karovska, Evan Tingle, Scott Wolk, Scott Engle, Edward Guinan, Ignazio Pillitteri, Charles Proffitt, Pierre Kervella, Alexandre Gallenne, Richard I. Anderson, and Maxwell Moe
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Astrophysics ,QB460-466 - Published
- 2024
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5. Spectroscopic Survey of Faint Planetary-nebula Nuclei. IV. The A35-type Central Star of Pa 27
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Howard E. Bond and Gregory R. Zeimann
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Planetary nebulae ,Planetary nebulae nuclei ,Starspots ,Stellar rotation ,Detached binary stars ,Astrophysics ,QB460-466 - Abstract
We present optical spectroscopy of the 12th-magnitude central star of the planetary nebula (PN) Patchick 27 (Pa 27), obtained during a survey of faint PN nuclei (PNNs) with the Low-Resolution Spectrograph of the Hobby–Eberly Telescope. The optical spectrum of Pa 27 is that of a K0 III red giant with rotationally broadened lines. However, the star is detected in the near-ultraviolet (near-UV) with GALEX, showing that a hot binary component is also present. The spectral-energy distribution from the near-UV to the mid-infrared can be fitted with a combination of the K0 III giant and a hot PNN with an effective temperature of about 50,000 K. Photometric observations of Pa 27, both ground-based and from TESS, show a low-amplitude sinusoidal variation with a period of 7.36 days, probably due to starspots on a rotating and magnetically active cool giant. Pa 27 is a new member of the rare class of “A35-type central stars,” which are binary PNNs consisting of a spotted late-type star and a hot pre–white dwarf. They are likely the result of a situation where an asymptotic-giant-branch (AGB) star ejects its outer layers in a dense wind, part of which is captured by a distant companion, spinning up its rotation by accretion of material and angular momentum. We suggest several useful follow-up observations.
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- 2024
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6. AT 2019qyl in NGC 300: Internal Collisions in the Early Outflow from a Very Fast Nova in a Symbiotic Binary* †
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Jacob E. Jencson, Jennifer E. Andrews, Howard E. Bond, Viraj Karambelkar, David J. Sand, Schuyler D. van Dyk, Nadejda Blagorodnova, Martha L. Boyer, Mansi M. Kasliwal, Ryan M. Lau, Shazrene Mohamed, Robert Williams, Patricia A. Whitelock, Rachael C. Amaro, K. Azalee Bostroem, Yize Dong, Michael J. Lundquist, Stefano Valenti, Samuel D. Wyatt, Jamie Burke, Kishalay De, Saurabh W. Jha, Joel Johansson, César Rojas-Bravo, David A. Coulter, Ryan J. Foley, Robert D. Gehrz, Joshua Haislip, Daichi Hiramatsu, D. Andrew Howell, Charles D. Kilpatrick, Frank J. Masci, Curtis McCully, Chow-Choong Ngeow, Yen-Chen Pan, Craig Pellegrino, Anthony L. Piro, Vladimir Kouprianov, Daniel E. Reichart, Armin Rest, Sofia Rest, and Nathan Smith
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- 2021
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7. An Isolated Stellar-mass Black Hole Detected through Astrometric Microlensing*
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Sahu, Kailash C., primary, Anderson, Jay, additional, Casertano, Stefano, additional, Bond, Howard E., additional, Udalski, Andrzej, additional, Dominik, Martin, additional, Calamida, Annalisa, additional, Bellini, Andrea, additional, Brown, Thomas M., additional, Rejkuba, Marina, additional, Bajaj, Varun, additional, Kains, Noé, additional, Ferguson, Henry C., additional, Fryer, Chris L., additional, Yock, Philip, additional, Mróz, Przemek, additional, Kozłowski, Szymon, additional, Pietrukowicz, Paweł, additional, Poleski, Radek, additional, Skowron, Jan, additional, Soszyński, Igor, additional, Szymański, Michał K., additional, Ulaczyk, Krzysztof, additional, Wyrzykowski, Łukasz, additional, Barry, Richard K., additional, Bennett, David P., additional, Bond, Ian A., additional, Hirao, Yuki, additional, Silva, Stela Ishitani, additional, Kondo, Iona, additional, Koshimoto, Naoki, additional, Ranc, Clément, additional, Rattenbury, Nicholas J., additional, Sumi, Takahiro, additional, Suzuki, Daisuke, additional, Tristram, Paul J., additional, Vandorou, Aikaterini, additional, Beaulieu, Jean-Philippe, additional, Marquette, Jean-Baptiste, additional, Cole, Andrew, additional, Fouqué, Pascal, additional, Hill, Kym, additional, Dieters, Stefan, additional, Coutures, Christian, additional, Dominis-Prester, Dijana, additional, Bennett, Clara, additional, Bachelet, Etienne, additional, Menzies, John, additional, Albrow, Michael, additional, Pollard, Karen, additional, Gould, Andrew, additional, Yee, Jennifer C., additional, Allen, William, additional, Almeida, Leonardo A., additional, Christie, Grant, additional, Drummond, John, additional, Gal-Yam, Avishay, additional, Gorbikov, Evgeny, additional, Jablonski, Francisco, additional, Lee, Chung-Uk, additional, Maoz, Dan, additional, Manulis, Ilan, additional, McCormick, Jennie, additional, Natusch, Tim, additional, Pogge, Richard W., additional, Shvartzvald, Yossi, additional, Jørgensen, Uffe G., additional, Alsubai, Khalid A., additional, Andersen, Michael I., additional, Bozza, Valerio, additional, Novati, Sebastiano Calchi, additional, Burgdorf, Martin, additional, Hinse, Tobias C., additional, Hundertmark, Markus, additional, Husser, Tim-Oliver, additional, Kerins, Eamonn, additional, Longa-Peña, Penelope, additional, Mancini, Luigi, additional, Penny, Matthew, additional, Rahvar, Sohrab, additional, Ricci, Davide, additional, Sajadian, Sedighe, additional, Skottfelt, Jesper, additional, Snodgrass, Colin, additional, Southworth, John, additional, Tregloan-Reed, Jeremy, additional, Wambsganss, Joachim, additional, Wertz, Olivier, additional, Tsapras, Yiannis, additional, Street, Rachel A., additional, Bramich, D. M., additional, Horne, Keith, additional, and Steele, Iain A., additional
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- 2022
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8. Yellow Post-asymptotic-giant-branch Stars as Standard Candles. I. Calibration of the Luminosity Function in Galactic Globular Clusters
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Ciardullo, Robin, primary, Bond, Howard E., additional, Davis, Brian D., additional, and Siegel, Michael H., additional
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- 2022
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9. Hubble Space Telescope Imaging of Luminous Extragalactic Infrared Transients and Variables from the Spitzer Infrared Intensive Transients Survey*
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Bond, Howard E., primary, Jencson, Jacob E., additional, Whitelock, Patricia A., additional, Adams, Scott M., additional, Bally, John, additional, Cody, Ann Marie, additional, Gehrz, Robert D., additional, Kasliwal, Mansi M., additional, and Masci, Frank J., additional
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- 2022
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10. A Census of Above-horizontal-branch Stars in Galactic Globular Clusters*
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Davis, Brian D., primary, Bond, Howard E., additional, Siegel, Michael H., additional, and Ciardullo, Robin, additional
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- 2022
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11. Hubble Space Telescope Astrometry of the Procyon System
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Bond, Howard E, Gilliland, Ronald L, Schaefer, Gail H, Demarque, Pierre, Girard, Terrence M, Holberg, Jay B, Gudehus, Donald, Mason, Brian D, Kozhurina-Platais, Vera, and Burleigh, Matthew R
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Astronomy - Abstract
The nearby star Procyon is a visual binary containing the F5 IV-V subgiant Procyon A, orbited in a 40.84-year period by the faint DQZ white dwarf (WD) Procyon B. Using images obtained over two decades with the Hubble Space Telescope, and historical measurements back to the 19th century, we have determined precise orbital elements. Combined with measurements of the parallax and the motion of the A component, these elements yield dynamical masses of 1.478 plus or minus 0.012M and 0.592 plus or minus 0.006M for A and B, respectively. The mass of Procyon A agrees well with theoretical predictions based on asteroseismology and its temperature and luminosity. Use of a standard core-overshoot model agrees best for a surprisingly high amount of core overshoot. Under these modeling assumptions, Procyon A's age is approximately 2.7 Gyr. Procyon B's location in the H-R diagram is in excellent agreement with theoretical cooling tracks for WDs of its dynamical mass. Its position in the mass-radius plane is also consistent with theory, assuming a carbon-oxygen core and a helium-dominated atmosphere. Its progenitor's mass was 1.9-2.2M, depending on its amount of core overshoot. Several astrophysical puzzles remain. In the progenitor system, the stars at periastron were separated by only approximately AU, which might have led to tidal interactions and even mass transfer; yet there is no direct evidence that these have occurred. Moreover the orbital eccentricity has remained high (approximately 0.40). The mass of Procyon B is somewhat lower than anticipated from the initial-to-final-mass relation seen in open clusters. The presence of heavy elements in its atmosphere requires ongoing accretion, but the place of origin is uncertain.
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- 2015
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12. AT 2019qyl in NGC 300: Internal Collisions in the Early Outflow from a Very Fast Nova in a Symbiotic Binary* †
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Jencson, Jacob E., primary, Andrews, Jennifer E., additional, Bond, Howard E., additional, Karambelkar, Viraj, additional, Sand, David J., additional, van Dyk, Schuyler D., additional, Blagorodnova, Nadejda, additional, Boyer, Martha L., additional, Kasliwal, Mansi M., additional, Lau, Ryan M., additional, Mohamed, Shazrene, additional, Williams, Robert, additional, Whitelock, Patricia A., additional, Amaro, Rachael C., additional, Bostroem, K. Azalee, additional, Dong, Yize, additional, Lundquist, Michael J., additional, Valenti, Stefano, additional, Wyatt, Samuel D., additional, Burke, Jamie, additional, De, Kishalay, additional, Jha, Saurabh W., additional, Johansson, Joel, additional, Rojas-Bravo, César, additional, Coulter, David A., additional, Foley, Ryan J., additional, Gehrz, Robert D., additional, Haislip, Joshua, additional, Hiramatsu, Daichi, additional, Howell, D. Andrew, additional, Kilpatrick, Charles D., additional, Masci, Frank J., additional, McCully, Curtis, additional, Ngeow, Chow-Choong, additional, Pan, Yen-Chen, additional, Pellegrino, Craig, additional, Piro, Anthony L., additional, Kouprianov, Vladimir, additional, Reichart, Daniel E., additional, Rest, Armin, additional, Rest, Sofia, additional, and Smith, Nathan, additional
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- 2021
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13. The Stars of the HETDEX Survey. I. Radial Velocities and Metal-Poor Stars from Low-Resolution Stellar Spectra
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Karl Gebhardt, Keith Hawkins, Christopher Sneden, Dustin Davis, Barbara G. Castanheira, Donald P. Schneider, Caitlin M. Casey, Andreas Kelz, J. Craig Wheeler, Steven L. Finkelstein, Daniel J. Farrow, Gary J. Hill, Erin Mentuch Cooper, Andreia Carrillo, Howard E. Bond, Robin Ciardullo, Greg Zeimann, Matthias Steinmetz, Matthew Shetrone, Chenxu Liu, Else Starkenburg, and Astronomy
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Physics ,010308 nuclear & particles physics ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Segue ,01 natural sciences ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Astronomical spectroscopy ,Spectral line ,law.invention ,LAMOST ,Telescope ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,13. Climate action ,Space and Planetary Science ,law ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Dark energy ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) - Abstract
The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is an unbiased, massively multiplexed spectroscopic survey, designed to measure the expansion history of the universe through low-resolution ($R\sim750$) spectra of Lyman-Alpha Emitters. In its search for these galaxies, HETDEX will also observe a few 10$^{5}$ stars. In this paper, we present the first stellar value-added catalog within the internal second data release of the HETDEX Survey (HDR2). The new catalog contains 120,571 low-resolution spectra for 98,736 unique stars between $10 < G < 22$ spread across the HETDEX footprint at relatively high ($b\sim60^\circ$) Galactic latitudes. With these spectra, we measure radial velocities (RVs) for $\sim$42,000 unique FGK-type stars in the catalog and show that the HETDEX spectra are sufficient to constrain these RVs with a 1$��$ precision of 28.0 km/s and bias of 3.5 km/s with respect to the LAMOST surveys and 1$��$ precision of 27.5 km/s and bias of 14.0 km/s compared to the SEGUE survey. Since these RVs are for faint ($G\geq16$) stars, they will be complementary to Gaia. Using t-Distributed Stochastic Neighbor Embedding (t-SNE), we also demonstrate that the HETDEX spectra can be used to determine a star's T${\rm{eff}}$, and log g and its [Fe/H]. With the t-SNE projection of the FGK-type stars with HETDEX spectra we also identify 416 new candidate metal-poor ([Fe/H] $< -1$~dex) stars for future study. These encouraging results illustrate the utility of future low-resolution stellar spectroscopic surveys., 18 Pages, 11 Figures, 2 Tables. Accepted to ApJ
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- 2021
14. A Census of Above-horizontal-branch Stars in Galactic Globular Clusters*
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Brian D. Davis, Howard E. Bond, Michael H. Siegel, and Robin Ciardullo
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Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,FOS: Physical sciences ,Astronomy and Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) - Abstract
We have carried out a search for above-horizontal-branch (AHB) stars--objects lying above the horizontal branch (HB) and blueward of the asymptotic giant branch (AGB) in the color-magnitude diagram--in 97 Galactic and seven Magellanic Cloud globular clusters (GCs). We selected AHB candidates based on photometry in the $uBVI$ system, which is optimized for detection of low-gravity stars with large Balmer jumps, in the color range $-0.05\le(B-V)_0\le1.0$. We then used $Gaia$ astrometry and Gaussian-mixture modeling to confirm cluster membership and remove field interlopers. Our final catalog contains 438 AHB stars, classified and interpreted in the context of post-HB evolution as follows: (1) AHB1: 280 stars fainter than $M_V=-0.8$, evolving redward from the blue HB (BHB) toward the base of the AGB. (2) Post-AGB (PAGB): 13 stars brighter than $M_V\simeq-2.75$, departing from the top of the AGB and evolving rapidly blueward. (3) AHB2: 145 stars, with absolute magnitudes between those of the AHB1 and PAGB groups. This last category includes a mixture of objects leaving the extreme BHB and evolving toward the AGB, and brighter ones moving back from the AGB toward higher temperatures. Among the AHB1 stars are 59 RR Lyrae interlopers, observed by chance in our survey near maximum light. PAGB and AHB2 stars (including W Virginis Cepheids) overwhelmingly belong to GCs containing BHB stars, in accordance with predictions of post-HB evolutionary tracks. We suggest that most W Vir variables are evolving toward lower temperatures and are in their first crossings of the instability strip. Non-variable yellow PAGB stars show promise as a Population II standard candle for distance measurement., Accepted by Astrophysical Journal. For machine-readable version of Table 3, see https://www.stsci.edu/~bond/ahb_stars_mrt.txt
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- 2022
15. The Stars of the HETDEX Survey. I. Radial Velocities and Metal-poor Stars from Low-resolution Stellar Spectra
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Hawkins, Keith, primary, Zeimann, Greg, additional, Sneden, Chris, additional, Cooper, Erin Mentuch, additional, Gebhardt, Karl, additional, Bond, Howard E., additional, Carrillo, Andreia, additional, Casey, Caitlin M., additional, Castanheira, Barbara G., additional, Ciardullo, Robin, additional, Davis, Dustin, additional, Farrow, Daniel J., additional, Finkelstein, Steven L., additional, Hill, Gary J., additional, Kelz, Andreas, additional, Liu, Chenxu, additional, Shetrone, Matthew, additional, Schneider, Donald P., additional, Starkenburg, Else, additional, Steinmetz, Matthias, additional, and Wheeler, J. Craig, additional
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- 2021
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16. Revealing Efficient Dust Formation at Low Metallicity in Extragalactic Carbon-rich Wolf-Rayet Binaries
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Lau, Ryan M., primary, Hankins, Matthew J., additional, Kasliwal, Mansi M., additional, Bond, Howard E., additional, De, Kishalay, additional, Jencson, Jacob E., additional, Moffat, Anthony F. J., additional, Smith, Nathan, additional, and Williams, Peredur M., additional
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- 2021
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17. Hubble Space Telescope Snapshot Survey for Resolved Companions of Galactic Cepheids: Final ResultsBased on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NASA5-26555. Based on observations made with the Chandra X-ray Observatory.
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Evans, Nancy Remage, primary, Günther, H. Moritz, additional, Bond, Howard E., additional, Schaefer, Gail H., additional, Mason, Brian D., additional, Karovska, Margarita, additional, Tingle, Evan, additional, Wolk, Scott, additional, Engle, Scott, additional, Guinan, Edward, additional, Pillitteri, Ignazio, additional, Proffitt, Charles, additional, Kervella, Pierre, additional, Gallenne, Alexandre, additional, Anderson, Richard I., additional, and Moe, Maxwell, additional
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- 2020
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18. Hubble Space Telescope Astrometry of the Metal-poor Visual Binary μ Cassiopeiae: Dynamical Masses, Helium Content, and Age
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Bond, Howard E., primary, Schaefer, Gail H., additional, Gilliland, Ronald L., additional, and VandenBerg, Don A., additional
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- 2020
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19. Discovery of a Rare Late-type, Low-mass Wolf–Rayet Star in the LMC
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Margon, Bruce, primary, Manea, Catherine, additional, Williams, Robert, additional, Bond, Howard E., additional, Prochaska, J. Xavier, additional, Szymański, Michał K., additional, and Morrell, Nidia, additional
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- 2020
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20. The Resolved Stellar Population in 50 Regions of M83 from HST/WFC3 Early Release Science Observations
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Kim, Hwihyun, Whitmore, Bradley C, Chandar, Rupali, Saha, Abhijit, Kaleida, Catherine C, Mutchler, Max, Cohen, Seth H, Calzetti, Daniela, O’Connell, Robert W, Windhorst, Rogier A, Balick, Bruce, Bond, Howard E, Carollo, Marcella, Disney, Michael J, Dopita, Michael A, Frogel, Jay A, Hall, Donald N. B, Holtzman, Jon A, Kimble, Randy A, McCarthy, Patrick J, Paresce, Francesco, Silk, Joe I, Trauger, John T, Walker, Alistair R, and Young, Erick T
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Astrophysics - Abstract
We present a multi-wavelength photometric study of approximately 15,000 resolved stars in the nearby spiral galaxy M83 (NGC 5236, D = 4.61 Mpc) based on Hubble Space Telescope Wide Field Camera 3 observations using four filters: F336W, F438W, F555W, and F814W. We select 50 regions (an average size of 260 pc by 280 pc) in the spiral arm and inter-arm areas of M83 and determine the age distribution of the luminous stellar populations in each region. This is accomplished by correcting for extinction toward each individual star by comparing its colors with predictions from stellar isochrones.We compare the resulting luminosity-weighted mean ages of the luminous stars in the 50 regions with those determined from several independent methods, including the number ratio of red-to-blue supergiants, morphological appearance of the regions, surface brightness fluctuations, and the ages of clusters in the regions. We find reasonably good agreement between these methods. We also find that young stars are much more likely to be found in concentrated aggregates along spiral arms, while older stars are more dispersed. These results are consistent with the scenario that star formation is associated with the spiral arms, and stars form primarily in star clusters and then disperse on short timescales to form the field population. The locations ofWolf-Rayet stars are found to correlate with the positions of many of the youngest regions, providing additional support for our ability to accurately estimate ages. We address the effects of spatial resolution on the measured colors, magnitudes, and age estimates. While individual stars can occasionally show measurable differences in the colors and magnitudes, the age estimates for entire regions are only slightly affected.
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- 2012
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21. Carbon-deficient Red Giants
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Bond, Howard E., primary
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- 2019
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22. The SPIRITS Sample of Luminous Infrared Transients: Uncovering Hidden Supernovae and Dusty Stellar Outbursts in Nearby Galaxies
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Jencson, Jacob E., primary, Kasliwal, Mansi M., additional, Adams, Scott M., additional, Bond, Howard E., additional, De, Kishalay, additional, Johansson, Joel, additional, Karambelkar, Viraj, additional, Lau, Ryan M., additional, Tinyanont, Samaporn, additional, Ryder, Stuart D., additional, Cody, Ann Marie, additional, Masci, Frank J., additional, Bally, John, additional, Blagorodnova, Nadejda, additional, Castellón, Sergio, additional, Fremling, Christoffer, additional, Gehrz, Robert D., additional, Helou, George, additional, Kilpatrick, Charles D., additional, Milne, Peter A., additional, Morrell, Nidia, additional, Perley, Daniel A., additional, Phillips, M. M., additional, Smith, Nathan, additional, van Dyk, Schuyler D., additional, and Williams, Robert E., additional
- Published
- 2019
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23. Carbon-deficient Red Giants
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Howard E. Bond
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Physics ,CNO cycle ,010504 meteorology & atmospheric sciences ,Stellar rotation ,Stellar parallax ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Galactic plane ,01 natural sciences ,Photometry (optics) ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,Binary star ,010303 astronomy & astrophysics ,Stellar evolution ,Solar and Stellar Astrophysics (astro-ph.SR) ,0105 earth and related environmental sciences - Abstract
Carbon-deficient red giants (CDRGs) are a rare class of peculiar red giants, also called "weak G-band" or "weak-CH" stars. Their atmospheric compositions show depleted carbon, a low 12C/13C isotopic ratio, and an overabundance of nitrogen, indicating that the material at the surface has undergone CN-cycle hydrogen-burning. I present Stromgren uvby photometry of nearly all known CDRGs. Barium stars, having an enhanced carbon abundance, exhibit the "Bond-Neff effect"--a broad depression in their energy distributions at ~4000 A, recently confirmed to be due to the CH molecule. This gives Ba II stars unusually low Stromgren c1 photometric indices. I show that CDRGs, lacking CH absorption, exhibit an "anti-Bond-Neff effect": higher c1 indices than normal red giants. Using precise parallaxes from Gaia DR2, I plot CDRGs in the color-magnitude diagram (CMD) and compare them with theoretical evolution tracks. Most CDRGs lie in a fairly tight clump in the CMD, indicating initial masses in the range ~2 to 3.5 Msun, if they have evolved as single stars. It is unclear whether they are stars that have just reached the base of the red-giant branch and the first dredge-up of CN-processed material, or are more highly evolved helium-burning stars in the red-giant clump. About 10% of CDRGs have higher masses of ~4 to 4.5 Msun, and exhibit unusually high rotational velocities. I show that CDRGs lie at systematically larger distances from the Galactic plane than normal giants, possibly indicating a role of binary mass-transfer and mergers. CDRGs continue to present a major puzzle for our understanding of stellar evolution., Comment: Accepted by Astrophysical Journal
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- 2019
24. The SPIRITS Sample of Luminous Infrared Transients: Uncovering Hidden Supernovae and Dusty Stellar Outbursts in Nearby Galaxies
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John Bally, Robert E. Williams, Charles D. Kilpatrick, Ann Marie Cody, George Helou, Frank J. Masci, Nadejda Blagorodnova, Schuyler D. Van Dyk, S. Castellon, Christoffer Fremling, Howard E. Bond, Scott M. Adams, Joel Johansson, Ryan M. Lau, Nathan Smith, V. Karambelkar, Peter Milne, Kaushik De, Robert D. Gehrz, Stuart D. Ryder, Nidia Morrell, Jacob E. Jencson, Mansi M. Kasliwal, Mark M. Phillips, Samaporn Tinyanont, and Daniel A. Perley
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010504 meteorology & atmospheric sciences ,Infrared ,Astronomy ,Extinction (astronomy) ,FOS: Physical sciences ,Astrophysics ,01 natural sciences ,supernovae: general ,0103 physical sciences ,Control sample ,010303 astronomy & astrophysics ,QC ,QB ,0105 earth and related environmental sciences ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,stars: massive ,Stars ,Supernova ,supernovae: individual (SPIRITS 14buu, SPIRITS 15c, SPIRITS 15ud, SPIRITS 16ix, SPIRITS 16tn, SPIRITS 17lb) ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Luminous red nova ,dust, extinction ,Astrophysics - High Energy Astrophysical Phenomena ,infrared: general - Abstract
著者人数: 26名, Accepted: 2019-09-30, 資料番号: SA1190117000
- Published
- 2019
25. Hubble Space Telescope Spectroscopy of a Planetary Nebula in an M31 Open Cluster: Hot-bottom Burning at 3.4 M ⊙
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Davis, Brian D., primary, Bond, Howard E., additional, Ciardullo, Robin, additional, and Jacoby, George H., additional
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- 2019
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26. Discovery of an Intermediate-luminosity Red Transient in M51 and Its Likely Dust-obscured, Infrared-variable Progenitor
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Jencson, Jacob E., primary, Adams, Scott M., additional, Bond, Howard E., additional, van Dyk, Schuyler D., additional, Kasliwal, Mansi M., additional, Bally, John, additional, Blagorodnova, Nadejda, additional, De, Kishalay, additional, Fremling, Christoffer, additional, Yao, Yuhan, additional, Fruchter, Andrew, additional, Rubin, David, additional, Barbarino, Cristina, additional, Sollerman, Jesper, additional, Miller, Adam A., additional, Hicks, Erin K. S., additional, Malkan, Matthew A., additional, Andreoni, Igor, additional, Bellm, Eric C., additional, Buchheim, Robert, additional, Dekany, Richard, additional, Feeney, Michael, additional, Frederick, Sara, additional, Gal-Yam, Avishay, additional, Gehrz, Robert D., additional, Giomi, Matteo, additional, Graham, Matthew J., additional, Green, Wayne, additional, Hale, David, additional, Hankins, Matthew J., additional, Hanson, Mark, additional, Helou, George, additional, Ho, Anna Y. Q., additional, Hung, T., additional, Jurić, Mario, additional, Kendurkar, Malhar R., additional, Kulkarni, S. R., additional, Lau, Ryan M., additional, Masci, Frank J., additional, Neill, James D., additional, Quin, Kevin, additional, Riddle, Reed L., additional, Rusholme, Ben, additional, Sims, Forrest, additional, Smith, Nathan, additional, Smith, Roger M., additional, Soumagnac, Maayane T., additional, Tachibana, Yutaro, additional, Tinyanont, Samaporn, additional, Walters, Richard, additional, Watson, Stanley, additional, and Williams, Robert E., additional
- Published
- 2019
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27. Hubble Space Telescope Spectroscopy of a Planetary Nebula in an M31 Open Cluster: Hot-bottom Burning at 3.4 M ⊙
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G. H. Jacoby, Robin Ciardullo, Howard E. Bond, and Brian D. Davis
- Subjects
Physics ,Andromeda Galaxy ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Planetary nebula ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Hubble space telescope ,Astrophysics::Solar and Stellar Astrophysics ,Asymptotic giant branch ,Astrophysics::Earth and Planetary Astrophysics ,Spectroscopy ,Astrophysics::Galaxy Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Open cluster - Abstract
We use imaging and spectroscopy from the Hubble Space Telescope (HST) to examine the properties of a bright planetary nebula (PN) projected within M31's young open cluster B477-D075. We show that the probability of a chance superposition of the PN on the cluster is small, ${\lesssim}2\%$. Moreover, the radial velocity of the PN is the same as that of the cluster within the measurement error of ${\sim}10$ km s$^{-1}$. Given the expected ${\sim}70$ km s$^{-1}$ velocity dispersion in this region, ${\sim}$8 kpc from M31's nucleus, the velocity data again make it extremely likely that the PN belongs to the cluster. Applying isochrone fitting to archival color-magnitude photometric data from the HST Advanced Camera for Surveys, we determine the cluster age and metallicity to be 290 Myr and $Z = 0.0071$, respectively, implying an initial mass of $3.38^{+0.03}_{-0.02} \, M_{\odot}$ for any PN produced by the cluster. From HST's Space Telescope Imaging Spectrograph observations and Cloudy photoionization modeling, we find that the PN is likely a Type I planetary, with a nitrogen abundance that is enhanced by ${\sim}$5-6 times over the solar value scaled to the cluster metallicity. If the PN is indeed a cluster member, these data present strong empirical evidence that hot-bottom burning occurs in AGB stars with initial masses as low as $3.4 \, M_{\odot}$., Comment: 18 pages, 5 figures, 4 tables
- Published
- 2019
28. The Orbit of the Close Companion of Polaris: Hubble Space Telescope Imaging, 2007 to 2014
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Evans, Nancy Remage, primary, Karovska, Margarita, additional, Bond, Howard E., additional, Schaefer, Gail H., additional, Sahu, Kailash C., additional, Mack, Jennifer, additional, Nelan, Edmund P., additional, Gallenne, Alexandre, additional, and Tingle, Evan D., additional
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- 2018
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29. SPIRITS 16tn in NGC 3556: A Heavily Obscured and Low-luminosity Supernova at 8.8 Mpc
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Jencson, Jacob E., primary, Kasliwal, Mansi M., additional, Adams, Scott M., additional, Bond, Howard E., additional, Lau, Ryan M., additional, Johansson, Joel, additional, Horesh, Assaf, additional, Mooley, Kunal P., additional, Fender, Robert, additional, De, Kishalay, additional, O’Sullivan, Dónal, additional, Masci, Frank J., additional, Cody, Ann Marie, additional, Blagorodnova, Nadia, additional, Fox, Ori D., additional, Gehrz, Robert D., additional, Milne, Peter A., additional, Perley, Daniel A., additional, Smith, Nathan, additional, and Van Dyk, Schuyler D., additional
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- 2018
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30. Hubble Space TelescopeTrigonometric Parallax of Polaris B, Companion of the Nearest Cepheid
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Bond, Howard E., primary, Nelan, Edmund P., additional, Evans, Nancy Remage, additional, Schaefer, Gail H., additional, and Harmer, Dianne, additional
- Published
- 2018
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31. SPIRITS 16tn in NGC 3556: A Heavily Obscured and Low-luminosity Supernova at 8.8 Mpc
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Mansi M. Kasliwal, Robert D. Gehrz, Frank J. Masci, Daniel A. Perley, Howard E. Bond, Jacob E. Jencson, Nathan Smith, Rob Fender, Ryan M. Lau, Assaf Horesh, Ann Marie Cody, O. D. Fox, Donal O'Sullivan, Joel Johansson, Scott M. Adams, Kunal Mooley, Peter Milne, Kaushik De, N. Blagorodnova, and Schuyler D. Van Dyk
- Subjects
High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,010308 nuclear & particles physics ,Infrared ,FOS: Physical sciences ,Infrared spectroscopy ,Astronomy and Astrophysics ,Astrophysics ,Light curve ,01 natural sciences ,Dust lane ,Supernova ,Space and Planetary Science ,0103 physical sciences ,Spectral energy distribution ,Astrophysics - High Energy Astrophysical Phenomena ,010303 astronomy & astrophysics ,QC ,QB - Abstract
We present the discovery by the SPitzer InfraRed Intensive Transients Survey (SPIRITS) of a likely supernova (SN) in NGC 3556 at only 8.8 Mpc, which, despite its proximity, was not detected by optical searches. A luminous infrared (IR) transient at $M_{[4.5]} = -16.7$ mag (Vega), SPIRITS 16tn is coincident with a dust lane in the inclined, star-forming disk of the host. Using IR, optical, and radio observations, we attempt to determine the nature of this event. We estimate $A_V \approx$ 8 - 9 mag of extinction, placing it among the three most highly obscured IR-discovered SNe to date. The [4.5] light curve declined at a rate of 0.013 mag day$^{-1}$, and the $[3.6] - [4.5]$ color grew redder from 0.7 to $\gtrsim$ 1.0 mag by 184.7 days post discovery. Optical/IR spectroscopy shows a red continuum, but no clearly discernible features, preventing a definitive spectroscopic classification. Deep radio observations constrain the radio luminosity of SPIRITS 16tn to $L_�� \lesssim 10^{24}$ erg s$^{-1}$ Hz$^{-1}$ between 3 - 15 GHz, excluding many varieties of radio core-collapse SNe. A type Ia SN is ruled out by the observed red IR color, and lack of features normally attributed to Fe-peak elements in the optical and IR spectra. SPIRITS 16tn was fainter at [4.5] than typical stripped-envelope SNe by $\approx$ 1 mag. Comparison of the spectral energy distribution to SNe II suggests SPIRITS 16tn was both highly obscured, and intrinsically dim, possibly akin to the low-luminosity SN 2005cs. We infer the presence of an IR dust echo powered by a peak luminosity of the transient of $5 \times 10^{40}$ erg s$^{-1} < L_{\mathrm{peak}} < 4\times10^{43}$ erg s$^{-1}$, consistent with the observed range for SNe II. This discovery illustrates the power of IR surveys to overcome the compounding effects of visible extinction and optically sub-luminous events in completing the inventory of nearby SNe., 25 pages, 10 figures, submitted to ApJ
- Published
- 2018
32. PROGRESSIVE STAR FORMATION IN THE YOUNG GALACTIC SUPER STAR CLUSTER NGC 3603
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Bruce Balick, Daniela Calzetti, Nino Panagia, Guido De Marchi, Loredana Spezzi, Bradley C. Whitmore, Michael A. Dopita, Joseph Silk, Abhijit Saha, Donald N. B. Hall, Francesco Paresce, Jay A. Frogel, Howard E. Bond, Michael John Disney, Giacomo Beccari, Alistair R. Walker, C. Marcella Carollo, Robert W. O'Connell, Rogier A. Windhorst, Patrick J. McCarthy, Morten Andersen, John T. Trauger, Jon Holtzman, Randy A. Kimble, and Erick T. Young
- Subjects
Physics ,Star formation ,FOS: Physical sciences ,myr ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Stars ,Star cluster ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Cluster (physics) ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Early release ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics - Abstract
Early release science observations of the cluster NGC3603 with the WFC3 on the refurbished HST allow us to study its recent star formation history. Our analysis focuses on stars with Halpha excess emission, a robust indicator of their pre-main sequence (PMS) accreting status. The comparison with theoretical PMS isochrones shows that 2/3 of the objects with Halpha excess emission have ages from 1 to 10 Myr, with a median value of 3 Myr, while a surprising 1/3 of them are older than 10 Myr. The study of the spatial distribution of these PMS stars allows us to confirm their cluster membership and to statistically separate them from field stars. This result establishes unambiguously for the first time that star formation in and around the cluster has been ongoing for at least 10-20 Myr, at an apparently increasing rate., 10 pages, 8 figures, accepted for publication in The Astrophysical Journal
- Published
- 2010
33. THE LUMINOSITY, MASS, AND AGE DISTRIBUTIONS OF COMPACT STAR CLUSTERS IN M83 BASED ONHUBBLE SPACE TELESCOPE/WIDE FIELD CAMERA 3 OBSERVATIONS
- Author
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John T. Trauger, Bruce Balick, Michael A. Dopita, Abhijit Saha, Francesco Paresce, Donald N. B. Hall, Marcella Carollo, Rogier A. Windhorst, Howard E. Bond, Joseph Silk, Jay A. Frogel, Hwihyun Kim, Patrick J. McCarthy, Bradley C. Whitmore, Max Mutchler, Robert W. O'Connell, Randy A. Kimble, Alistair R. Walker, Rupali Chandar, Jon A. Holtzman, Catherine C. Kaleida, Erick T. Young, Michael John Disney, and Daniela Calzetti
- Subjects
Physics ,Spiral galaxy ,Stellar population ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Compact star ,01 natural sciences ,Power law ,Luminosity ,Stars ,Space and Planetary Science ,0103 physical sciences ,010303 astronomy & astrophysics ,Wide Field Camera 3 ,Astrophysics::Galaxy Astrophysics ,Luminosity function (astronomy) - Abstract
The newly installed Wide Field Camera 3 (WFC3) on the Hubble Space Telescope has been used to obtain multi-band images of the nearby spiral galaxy M83. These new observations are the deepest and highest resolution images ever taken of a grand-design spiral, particularly in the near ultraviolet, and allow us to better differentiate compact star clusters from individual stars and to measure the luminosities of even faint clusters in the U band. We find that the luminosity function for clusters outside of the very crowded starburst nucleus can be approximated by a power law, dN/dL \propto L^{alpha}, with alpha = -2.04 +/- 0.08, down to M_V ~ -5.5. We test the sensitivity of the luminosity function to different selection techniques, filters, binning, and aperture correction determinations, and find that none of these contribute significantly to uncertainties in alpha. We estimate ages and masses for the clusters by comparing their measured UBVI,Halpha colors with predictions from single stellar population models. The age distribution of the clusters can be approximated by a power-law, dN/dt propto t^{gamma}, with gamma=-0.9 +/- 0.2, for M > few x 10^3 Msun and t < 4x10^8 yr. This indicates that clusters are disrupted quickly, with ~80-90% disrupted each decade in age over this time. The mass function of clusters over the same M-t range is a power law, dN/dM propto M^{beta}, with beta=-1.94 +/- 0.16, and does not have bends or show curvature at either high or low masses. Therefore, we do not find evidence for a physical upper mass limit, M_C, or for the earlier disruption of lower mass clusters when compared with higher mass clusters, i.e. mass-dependent disruption. We briefly discuss these implications for the formation and disruption of the clusters.
- Published
- 2010
34. SUPERNOVA REMNANTS AND THE INTERSTELLAR MEDIUM OF M83: IMAGING AND PHOTOMETRY WITH THE WIDE FIELD CAMERA 3 ON THEHUBBLE SPACE TELESCOPE
- Author
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Michael A. Dopita, Daniela Calzetti, John T. Trauger, Erick T. Young, Rogier A. Windhorst, Patrick J. McCarthy, Marcella Carollo, Francesco Paresce, Donald N. B. Hall, Jon A. Holtzman, Kip D. Kuntz, Marco Sirianni, Knox S. Long, Howard E. Bond, William P. Blair, Robert W. O'Connell, Michael John Disney, Bruce Balick, Joseph Silk, Abhijit Saha, Jay A. Frogel, Bradley C. Whitmore, John W. MacKenty, Alistair R. Walker, Max Mutchler, and Randy A. Kimble
- Subjects
Physics ,education.field_of_study ,Spiral galaxy ,Population ,Doubly ionized oxygen ,Astronomy ,Astronomy and Astrophysics ,Astrophysics ,Galaxy ,Interstellar medium ,Supernova ,Space and Planetary Science ,education ,Supernova remnant ,Wide Field Camera 3 - Abstract
We present Wide Field Camera 3 images taken with the Hubble Space Telescope within a single field in the southern grand design star-forming galaxy M83. Based on their size, morphology, and photometry in continuum-subtracted Hα, [S II], Hβ, [O III], and [O II] filters, we have identified 60 supernova remnant (SNR) candidates, as well as a handful of young ejecta-dominated candidates. A catalog of these remnants, their sizes and, where possible, their Hα fluxes are given. Radiative ages and pre-shock densities are derived from those SNRs that have good photometry. The ages lie in the range 2.62 < log (τrad/yr) < 5.0, and the pre-shock densities at the blast wave range over 0.56 < n 0/cm-3 < 1680. Two populations of SNRs have been discovered. These divide into a nuclear and spiral arm group and an inter-arm population. We infer an arm to inter-arm density contrast of 4. The surface flux in diffuse X-rays is correlated with the inferred pre-shock density, indicating that the warm interstellar medium (ISM) is pressurized by the hot X-ray plasma. We also find that the ISM in the nuclear region of M83 is characterized by a very high porosity and pressure, and infer an SNR rate of 1 per 70-150 yr for the nuclear (R < 300 pc) region. On the basis of the number of SNRs detected and their radiative ages, we infer that the lower mass of Type II SNe in M83 is M min = 16+7 –5 M ☉. Finally, we give evidence for the likely detection of the remnant of the historical supernova, SN1968L.
- Published
- 2010
35. THE EXPANDING NEBULAR REMNANT OF THE RECURRENT NOVA RS OPHIUCHI (2006). II. MODELING OF COMBINEDHUBBLE SPACE TELESCOPEIMAGING AND GROUND-BASED SPECTROSCOPY
- Author
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V. H. Chavushyan, J. Bohigas, Rafael Costero, A. M. Newsam, Roger Coziol, Howard E. Bond, Sumner Starrfield, Tim O'Brien, Jonathan León-Tavares, Gaghik H. Tovmassian, Juan Echevarria, D. J. Harman, Michael G. Richer, S. P. S. Eyres, M. J. Darnley, Sergey Zharikov, A. Evans, Michael F. Bode, and Valério A. R. M. Ribeiro
- Subjects
Physics ,Line-of-sight ,Red giant ,Epoch (astronomy) ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,White dwarf ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Spectral line ,Orbit ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,RS Ophiuchi ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Ejecta ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics - Abstract
We report Hubble Space Telescope imaging, obtained 155 and 449 days after the 2006 outburst of the recurrent nova RS Ophiuchi, together with ground-based spectroscopic observations, obtained from the Observatorio Astron\'omico Nacional en San Pedro M\'artir, Baja California, M\'exico and at the Observatorio Astrof\'isico Guillermo Haro, at Cananea, Sonora, M\'exico. The observations at the first epoch were used as inputs to model the geometry and kinematic structure of the evolving RS Oph nebular remnant. We find that the modeled remnant comprises two distinct co-aligned bipolar components; a low-velocity, high-density innermost (hour glass) region and a more extended, high-velocity (dumbbell) structure. This overall structure is in agreement with that deduced from radio observations and optical interferometry at earlier epochs. We find that the asymmetry observed in the west lobe is an instrumental effect caused by the profile of the HST filter and hence demonstrate that this lobe is approaching the observer. We then conclude that the system has an inclination to the line of sight of 39$^{+1}_{-10}$ degrees. This is in agreement with the inclination of the binary orbit and lends support to the proposal that this morphology is due to the interaction of the outburst ejecta with either an accretion disk around the central white dwarf and/or a pre-existing red giant wind that is significantly denser in the equatorial regions of the binary than at the poles. The second epoch HST observation was also modeled. However, as no spectra were taken at this epoch, it is more difficult to constrain any model. Nevertheless, we demonstrate that between the two HST epochs the outer dumbbell structure seems to have expanded linearly., Comment: 33 pages, 9 figures, 1 table, accepted for publication in ApJ
- Published
- 2009
36. THE 2008 LUMINOUS OPTICAL TRANSIENT IN THE NEARBY GALAXY NGC 300
- Author
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Roberta M. Humphreys, L. A. G. Berto Monard, Howard E. Bond, Alceste Z. Bonanos, J. L. Prieto, Frederick M. Walter, and Luigi R. Bedin
- Subjects
Physics ,Photosphere ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Hypergiant ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Supernova ,Supernova impostor ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Bipolar outflow ,Astrophysics::Solar and Stellar Astrophysics ,Luminous red nova ,Astrophysics::Earth and Planetary Astrophysics ,Supergiant ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
A luminous optical transient (OT) that appeared in NGC 300 in early 2008 had a maximum brightness, M_V ~ -12 to -13, intermediate between classical novae and supernovae. We present ground-based photometric and spectroscopic monitoring and adaptive-optics imaging of the OT, as well as pre- and post-outburst space-based imaging with HST and Spitzer. The optical spectrum at maximum showed an F-type supergiant photosphere with superposed emission lines of hydrogen, Ca II, and [Ca II], similar to the spectra of low-luminosity Type IIn "supernova impostors" like SN 2008S, as well as cool hypergiants like IRC +10420. The emission lines have a complex, double structure, indicating a bipolar outflow with velocities of ~75 km/s. The luminous energy released in the eruption was ~10^47 ergs, most of it emitted in the first 2 months. By registering new HST images with deep archival frames, we have precisely located the OT site, and find no detectable optical progenitor brighter than broad-band V magnitude 28.5. However, archival Spitzer images reveal a bright, non-variable mid-IR pre-outburst source. We conclude that the NGC 300 OT was a heavily dust-enshrouded luminous star, of ~10-15 Msun, which experienced an eruption that cleared the surrounding dust and initiated a bipolar wind. The progenitor was likely an OH/IR source which had begun to evolve on a blue loop toward higher temperatures, but the precise cause of the outburst remains uncertain., Revised version, accepted by ApJ Letters. 7 pages, 4 figures
- Published
- 2009
37. Astrophysical Implications of a New Dynamical Mass for the Nearby White Dwarf 40 Eridani B
- Author
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Bond, Howard E., primary, Bergeron, P., additional, and Bédard, A., additional
- Published
- 2017
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38. The Sirius System and Its Astrophysical Puzzles:Hubble Space Telescopeand Ground-based Astrometry
- Author
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Bond, Howard E., primary, Schaefer, Gail H., additional, Gilliland, Ronald L., additional, Holberg, Jay B., additional, Mason, Brian D., additional, Lindenblad, Irving W., additional, Seitz-McLeese, Miranda, additional, Arnett, W. David, additional, Demarque, Pierre, additional, Spada, Federico, additional, Young, Patrick A., additional, Barstow, Martin A., additional, Burleigh, Matthew R., additional, and Gudehus, Donald, additional
- Published
- 2017
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39. SPIRITS: Uncovering Unusual Infrared Transients withSpitzer
- Author
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Kasliwal, Mansi M., primary, Bally, John, additional, Masci, Frank, additional, Cody, Ann Marie, additional, Bond, Howard E., additional, Jencson, Jacob E., additional, Tinyanont, Samaporn, additional, Cao, Yi, additional, Contreras, Carlos, additional, Dykhoff, Devin A., additional, Amodeo, Samuel, additional, Armus, Lee, additional, Boyer, Martha, additional, Cantiello, Matteo, additional, Carlon, Robert L., additional, Cass, Alexander C., additional, Cook, David, additional, Corgan, David T., additional, Faella, Joseph, additional, Fox, Ori D., additional, Green, Wayne, additional, Gehrz, R. D., additional, Helou, George, additional, Hsiao, Eric, additional, Johansson, Joel, additional, Khan, Rubab M., additional, Lau, Ryan M., additional, Langer, Norbert, additional, Levesque, Emily, additional, Milne, Peter, additional, Mohamed, Shazrene, additional, Morrell, Nidia, additional, Monson, Andy, additional, Moore, Anna, additional, Ofek, Eran O., additional, Sullivan, Donal O’, additional, Parthasarathy, Mudumba, additional, Perez, Andres, additional, Perley, Daniel A., additional, Phillips, Mark, additional, Prince, Thomas A., additional, Shenoy, Dinesh, additional, Smith, Nathan, additional, Surace, Jason, additional, Dyk, Schuyler D. Van, additional, Whitelock, Patricia A., additional, and Williams, Robert, additional
- Published
- 2017
- Full Text
- View/download PDF
40. SPIRITS 15c and SPIRITS 14buu: Two Obscured Supernovae in the Nearby Star-forming Galaxy IC 2163
- Author
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Jencson, Jacob E., primary, Kasliwal, Mansi M., additional, Johansson, Joel, additional, Contreras, Carlos, additional, Castellón, Sergio, additional, Bond, Howard E., additional, Monson, Andrew J., additional, Masci, Frank J., additional, Cody, Ann Marie, additional, Andrews, Jennifer E., additional, Bally, John, additional, Cao, Yi, additional, Fox, Ori D., additional, Gburek, Timothy, additional, Gehrz, Robert D., additional, Green, Wayne, additional, Helou, George, additional, Hsiao, Eric, additional, Morrell, Nidia, additional, Phillips, Mark, additional, Prince, Thomas A., additional, Simcoe, Robert A., additional, Smith, Nathan, additional, Tinyanont, Samaporn, additional, and Williams, Robert, additional
- Published
- 2017
- Full Text
- View/download PDF
41. Masses of the Planetary Nebula Central Stars in the Galactic Globular Cluster System fromHSTImaging and Spectroscopy
- Author
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Jacoby, George H., primary, Marco, Orsola De, additional, Davies, James, additional, Lotarevich, I., additional, Bond, Howard E., additional, Harrington, J. Patrick, additional, and Lanz, Thierry, additional
- Published
- 2017
- Full Text
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42. Hubble Space Telescope Imaging of the Expanding Nebular Remnant of the 2006 Outburst of the Recurrent Nova RS Ophiuchi
- Author
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Sumner Starrfield, M. F. Bode, A. Evans, S. P. S. Eyres, Tim O'Brien, Howard E. Bond, D. J. Harman, and M. J. Darnley
- Subjects
Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Doubly ionized oxygen ,Cataclysmic variable star ,White dwarf ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Planetary nebula ,Supernova ,Space and Planetary Science ,RS Ophiuchi ,Astrophysics::Solar and Stellar Astrophysics ,Ejecta ,Astrophysics::Galaxy Astrophysics ,Line (formation) - Abstract
We report Hubble Space Telescope imaging obtained 155 days after the 2006 outburst of RS Ophiuchi. We detect extended emission in both [O III] λ5007 and [Ne V] λ3426 lines. In both lines, the remnant has a double ring structure. The east-west orientation and total extent of these structures (580 ± 50 AU at d = 1.6 kpc) is consistent with that expected due to expansion of emitting regions imaged earlier in the outburst at radio wavelengths. Expansion at high velocity appears to have been roughly constant in the east-west direction (vexp = 3200 ± 300 km s-1 in the plane of the sky), with tentative evidence of deceleration north-south. We present a bipolar model of the remnant whose inclination is consistent with that of the central binary. The true expansion velocities of the polar components are then v = 5600 ± 1100 km s-1. We suggest that the bipolar morphology of the remnant results from interaction of the outburst ejecta with a circumstellar medium that is significantly denser in the equatorial regions of the binary than at the poles. This is also consistent with observations of shock evolution in the X-ray and the possible presence of dust in the infrared. Furthermore, it is in line with models of the shaping of planetary nebulae with close binary central systems, and also with recent observations relating to the progenitors of Type Ia supernovae, for which recurrent novae are a proposed candidate. Our observations also reveal more extended structures to the south and east of the remnant whose possible origin is briefly discussed.
- Published
- 2007
43. OBSERVATIONAL CONFIRMATION OF A LINK BETWEEN COMMON ENVELOPE BINARY INTERACTION AND PLANETARY NEBULA SHAPING
- Author
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Hillwig, Todd C., primary, Jones, David, additional, Marco, Orsola De, additional, Bond, Howard E., additional, Margheim, Steve, additional, and Frew, David, additional
- Published
- 2016
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44. The Progenitor of the Type II-P SN 2004dj in NGC 2403
- Author
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Dovi Poznanski, Y. Lipkin, Howard E. Bond, Eran O. Ofek, Michael H. Siegel, Jesús Maíz-Apellániz, and Dan Maoz
- Subjects
Physics ,Stellar population ,Stellar mass ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Galaxy ,Photometry (optics) ,Stars ,Supernova ,Space and Planetary Science ,Red supergiant ,Supergiant - Abstract
The Type II-P supernova 2004dj in the nearby galaxy NGC 2403 occurred at a position coincident with object 96 in the list of luminous stars and clusters in this galaxy published by Sandage in 1984. The coincidence is established definitively through astrometric registration of our ground-based archival images of NGC 2403 with our recent images showing the SN. The archival images show that Sandage 96 is slightly resolved from the ground. Pre-outburst blue spectrograms obtained by Humphreys and Aaronson reveal that Sandage 96 has a composite spectrum, dominated in the blue region by A- and B-type stars, while infrared photometry shows that Sandage 96 also contains red supergiants. These results demonstrate that Sandage 96 is a young compact cluster. We have studied the stellar population of Sandage 96, using published photometric measurements combined with a chi-square-fitting code. We derive a cluster age of 13.6 Ma, a reddening of E(4405-5495)=0.172, and a total stellar mass of 24 000 M_Sun. For this cluster age, the SN progenitor had a main-sequence mass of 15 M_Sun. Post-outburst photometry of Sandage 96 may establish whether the progenitor was a red or blue supergiant., Comment: Accepted for publication in ApJL. Replaces previous version not revised by the referee.13 pages, 3 figures
- Published
- 2004
45. A Chandra Low Energy Transmission Grating Spectrometer Observation of V4743 Sagittarii: A Supersoft X-Ray Source and a Violently Variable Light Curve
- Author
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J. W. Truran, Peter H. Hauschildt, Robert D. Gehrz, Marina Orio, Yousaf M. Butt, Howard E. Bond, R. M. Wagner, Jan-Uwe Ness, Charles E. Woodward, J. Krautter, J. J. Drake, Vadim Burwitz, Solen Balman, R. Wichmann, Sumner Starrfield, Koji Mukai, and M. Hernanz
- Subjects
Physics ,Wavelength ,Amplitude ,Spectrometer ,Space and Planetary Science ,Continuous spectrum ,White dwarf ,Astronomy ,Astronomy and Astrophysics ,Emission spectrum ,Astrophysics ,Light curve ,Absorption (electromagnetic radiation) - Abstract
V4743 Sagittarii (Nova Sgr 2002 No. 3) was discovered on 2002 September 20. We obtained a 5 ks ACIS-S spectrum in 2002 November and found that the nova was faint in X-rays. We then obtained a 25 ks Chandra Low Energy Transmission Grating Spectrometer (LETGS) observation on 2003 March 19. By this time, it had evolved into the supersoft X-ray phase exhibiting a continuous spectrum with deep absorption features. The light curve from the observation showed large-amplitude oscillations with a period of 1325 s (22 minutes) followed by a decline in the total count rate after ~13 ks of observations. The count rate dropped from ~40 counts s-1 to practically zero within ~6 ks and stayed low for the rest of the observation (~6 ks). The spectral hardness ratio changed from maxima to minima in correlation with the oscillations and then became significantly softer during the decay. Strong H-like and He-like lines of oxygen, nitrogen, and carbon were found in absorption during the bright phase, indicating temperatures between 1 and 2 MK, but they were shifted in wavelength corresponding to a Doppler velocity of -2400 km s-1. The spectrum obtained after the decline in count rate showed emission lines of C VI, N VI, and N VII, suggesting that we were seeing expanding gas ejected during the outburst, probably originating from CNO-cycled material. An XMM-Newton Target of Opportunity observation, obtained on 2002 April 4 and a later LETGS observation from 2003 July 18 also showed oscillations, but with smaller amplitudes.
- Published
- 2003
46. Astrophysical Implications of a New Dynamical Mass for the Nearby White Dwarf 40 Eridani B
- Author
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Pierre Bergeron, Howard E. Bond, and A. Bédard
- Subjects
Physics ,Orbital elements ,010308 nuclear & particles physics ,FOS: Physical sciences ,White dwarf ,Astronomy and Astrophysics ,Astrometry ,Radius ,Astrophysics ,Effective temperature ,Surface gravity ,01 natural sciences ,Luminosity ,Astrophysics - Solar and Stellar Astrophysics ,13. Climate action ,Space and Planetary Science ,Observatory ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics - Abstract
The bright, nearby DA-type white dwarf (WD) 40 Eridani B is orbited by the M dwarf 40 Eri C, allowing determination of the WD's mass. Until recently, however, the mass depended on orbital elements determined four decades ago, and that mass was so low that it created several astrophysical puzzles. Using new astrometric measurements, the binary-star group at the U.S. Naval Observatory has revised the dynamical mass upward, to $0.573\pm0.018\,M_\odot$. In this paper we use model-atmosphere analysis to update other parameters of the WD, including effective temperature, surface gravity, radius, and luminosity. We then compare these results with WD interior models. Within the observational uncertainties, theoretical cooling tracks for CO-core WDs of its measured mass are consistent with the position of 40 Eri B in the H-R diagram; equivalently, the theoretical mass-radius relation (MRR) is consistent with the star's location in the mass-radius plane. This consistency is, however, achieved only if we assume a "thin" outer hydrogen layer, with $q_{\rm H}=M_{\rm H}/M_{\rm WD}\simeq10^{-10}$. We discuss other evidence that a significant fraction of DA WDs have such thin H layers, in spite of expectation from canonical stellar-evolution theory of "thick" H layers with $q_{\rm H}\simeq10^{-4}$. The cooling age of 40 Eri B is $\sim$122 Myr, and its total age is $\sim$1.8 Gyr. We present the MRRs for 40 Eri B and three other nearby WDs in visual binaries with precise mass determinations, and show that the agreement of current theory with observation is excellent in all cases., Comment: Accepted by Astrophysical Journal
- Published
- 2017
47. The Sirius System and Its Astrophysical Puzzles:Hubble Space Telescopeand Ground-based Astrometry
- Author
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Federico Spada, Howard E. Bond, Gail Schaefer, Irving W. Lindenblad, Brian D. Mason, Martin A. Barstow, Miranda Seitz-McLeese, D. H. Gudehus, Patrick A. Young, Matthew R. Burleigh, Jay B. Holberg, Ronald L. Gilliland, W. David Arnett, and Pierre Demarque
- Subjects
Physics ,Orbital elements ,030503 health policy & services ,Metallicity ,Sirius ,FOS: Physical sciences ,White dwarf ,Astronomy and Astrophysics ,Orbital eccentricity ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrometry ,01 natural sciences ,03 medical and health sciences ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,0305 other medical science ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics ,Visual binary - Abstract
Sirius, the seventh-nearest stellar system, is a visual binary containing the metallic-line A1 V star Sirius A, brightest star in the sky, orbited in a 50.13-year period by Sirius B, the brightest and nearest white dwarf (WD). Using images obtained over nearly two decades with the Hubble Space Telescope (HST), along with photographic observations covering almost 20 years, and nearly 2300 historical measurements dating back to the 19th century, we determine precise orbital elements for the visual binary. Combined with the parallax and the motion of the A component, these elements yield dynamical masses of 2.063+/-0.023 Msun and 1.018+/-0.011 Msun for Sirius A and B, respectively. Our precise HST astrometry rules out third bodies orbiting either star in the system, down to masses of ~15-25 Mjup. The location of Sirius B in the H-R diagram is in excellent agreement with theoretical cooling tracks for WDs of its dynamical mass, and implies a cooling age of ~126 Myr. The position of Sirius B in the mass-radius plane is also consistent with WD theory, assuming a carbon-oxygen core. Including the pre-WD evolutionary timescale of the assumed progenitor, the total age of Sirius B is about 228+/-10 Myr. We calculated evolutionary tracks for stars with the dynamical mass of Sirius A, using two independent codes. We find it necessary to assume a slightly sub-solar metallicity, of about 0.85 Zsun, to fit its location in the luminosity-radius plane. The age of Sirius A based on these models is about 237-247 Myr, with uncertainties of +/-15 Myr, consistent with that of the WD companion. We discuss astrophysical puzzles presented by the Sirius system, including the probability that the two stars must have interacted in the past, even though there is no direct evidence for this, and the orbital eccentricity remains high., Comment: Accepted by Astrophysical Journal
- Published
- 2017
48. Detection of Coronal Mass Ejections in V471 Tauri with theHubble Space Telescope
- Author
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M. Sean O'Brien, Howard E. Bond, D. J. Mullan, and Edward M. Sion
- Subjects
Physics ,Line-of-sight ,Astrophysics (astro-ph) ,FOS: Physical sciences ,White dwarf ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Orbital period ,Orbit ,Orders of magnitude (time) ,Space and Planetary Science ,Ionization ,Coronal mass ejection ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Spectrograph ,Astrophysics::Galaxy Astrophysics - Abstract
V471 Tauri, an eclipsing system consisting of a hot DA white dwarf (WD) and a dK2 companion in a 12.5-hour orbit, is the prototype of the pre-cataclysmic binaries. The late-type component is magnetically active, due to its being constrained to rotate synchronously with the short orbital period. During a program of UV spectroscopy of V471 Tau, carried out with the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope, we serendipitously detected two episodes in which transient absorptions in the Si III 1206 A resonance line appeared suddenly, on a timescale of, 24 pages AASTeX, 4 figures. Accepted by Astrophysical Journal
- Published
- 2001
49. OBSERVATIONAL CONFIRMATION OF A LINK BETWEEN COMMON ENVELOPE BINARY INTERACTION AND PLANETARY NEBULA SHAPING
- Author
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David Jones, Orsola De Marco, Howard E. Bond, David J. Frew, Steve Margheim, and Todd C. Hillwig
- Subjects
Physics ,Orbital elements ,Nebula ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Binary number ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Planetary nebula ,Stars ,Common envelope ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Primary (astronomy) ,0103 physical sciences ,Binary star ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics - Abstract
A current issue in the study of planetary nebulae with close binary central stars is the extent to which the binaries affect the shaping of the nebulae. Recent studies have begun to show a high coincidence rate between nebulae with large-scale axial or point symmetries and close binary stars. In addition, combined binary-star and spatio-kinematic modeling of the nebulae have demonstrated that all of the systems studied to date appear to have their central binary axis aligned with the primary axis of the nebula. Here we add two more systems to the list, the central stars and nebulae of NGC 6337 and Sp 1. We show both systems to be low inclination, with their binary axis nearly aligned with our line-of-sight. Their inclinations match published values for the inclinations of their surrounding nebulae. Including these two systems with the existing sample statistically demonstrates a direct link between the central binary and the nebular morphology. In addition to the systems' inclinations we give ranges for other orbital parameters from binary modeling, including updated orbital periods for the binary central stars of NGC 6337 and Sp 1., Accepted for publication in the Astrophysical Journal. In the previously uploaded version of this paper, Figure 7 was displayed rotated 180 degrees. That and minor additional editorial items have been corrected
- Published
- 2016
50. RISING FROM THE ASHES: MID-INFRARED RE-BRIGHTENING OF THE IMPOSTOR SN 2010da IN NGC 300
- Author
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Lau, Ryan M., primary, Kasliwal, Mansi M., additional, Bond, Howard E., additional, Smith, Nathan, additional, Fox, Ori D., additional, Carlon, Robert, additional, Cody, Ann Marie, additional, Contreras, Carlos, additional, Dykhoff, Devin, additional, Gehrz, Robert, additional, Hsiao, Eric, additional, Jencson, Jacob, additional, Khan, Rubab, additional, Masci, Frank, additional, Monard, L. A. G., additional, Monson, Andrew J., additional, Morrell, Nidia, additional, Phillips, Mark, additional, and Ressler, Michael E., additional
- Published
- 2016
- Full Text
- View/download PDF
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