Institution
Smithsonian Astrophysical Observatory
Facility•Cambridge, Massachusetts, United States•
About: Smithsonian Astrophysical Observatory is a facility organization based out in Cambridge, Massachusetts, United States. It is known for research contribution in the topics: Galaxy & Stars. The organization has 1665 authors who have published 3622 publications receiving 132183 citations. The organization is also known as: SAO.
Topics: Galaxy, Stars, Telescope, Luminosity, Star formation
Papers published on a yearly basis
Papers
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TL;DR: In this paper, the authors estimate the merger rate of double degenerate binaries containing extremely low mass (ELM) < 0.3 Msun white dwarfs in the Galaxy.
Abstract: We estimate the merger rate of double degenerate binaries containing extremely low mass (ELM) <0.3 Msun white dwarfs in the Galaxy. Such white dwarfs are detectable for timescales of 0.1 Gyr -- 1 Gyr in the ELM Survey; the binaries they reside in have gravitational wave merger times of 0.001 Gyr -- 100 Gyr. To explain the observed distribution requires that most ELM white dwarf binary progenitors detach from the common envelope phase with <1 hr orbital periods. We calculate the local space density of ELM white dwarf binaries and estimate a merger rate of 3e-3/yr over the entire disk of the Milky Way; the merger rate in the halo is 10 times smaller. The ELM white dwarf binary merger rate exceeds by a factor of 40 the formation rate of stable mass transfer AM CVn binaries, marginally exceeds the rate of underluminous supernovae, and is identical to the formation rate of R CrB stars. On this basis, we conclude that ELM white dwarf binaries can be the progenitors of all observed AM CVn and possibly underluminous supernovae, however the majority of He+CO white dwarf binaries go through unstable mass transfer and merge, e.g. into single massive ~1 Msun white dwarfs.
61 citations
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TL;DR: The authors analyzes Ca II K-line profiles of one flare and EUV continuum observations of two other flares in an effort to obtain values for temperature enhancements over active region values produced in the upper photosphere around and above the temperature minimum region.
Abstract: The paper analyzes Ca II K-line profiles of one flare and EUV continuum observations of two other flares in an effort to obtain values for temperature enhancements over active region values produced in the upper photosphere around and above the temperature minimum region. Results show that the flare temperature minimum is depressed some two scale heights below its preflare level and that substantial temperature enhancements are produced even at this depth. Consideration is also given to possible heating mechanisms which might be responsible for the observed enhancements, including (1) heating by EUV radiation, (2) heating by proton beams with low dispersion energy spectra centered at 10-20 MeV, and (3) localized heating at temperature minimum levels.
61 citations
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TL;DR: In this article, the authors investigated the near-surface meteorology in the northern hemisphere of Mars through detailed analysis of data obtained with Mars Global Surveyor in January-August 2005 and found that the season in the Northern Hemisphere ranged from midsummer through winter solstice of Mars Year (MY) 27.
61 citations
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TL;DR: The derivation of the preflight photometric calibration of the uv spectrometer on Skylab is described, and an uncertainty of +/-35% is assigned over most of the 296-1340-A wavelength range.
Abstract: This paper describes the derivation of the preflight photometric calibration of the UV spectrometer on Skylab. The calibration of the orbiting instrument through cross-comparison with two rocket instruments is discussed in assessing the observed changes in response to quiet solar regions during the mission. Formulas are presented for the determination of the instrument sensitivity, and an uncertainty of plus or minus 35% is assigned over most of the 296-1340-A wavelength range.
61 citations
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TL;DR: In this paper, the authors observed a Cepheid pulsing in the fundamental mode and one pulsating in the first overtone with the Canadian MOST satellite, and they presented arguments that they are seeing instability in the pulsation cycle of the overtone pulsator.
Abstract: The quantity and quality of satellite photometric data strings is revealing details in Cepheid
variation at very low levels. Specifically, we observed a Cepheid pulsating in the fundamental
mode and one pulsating in the first overtone with the Canadian MOST satellite. The 3.7-d
period fundamental mode pulsator (RT Aur) has a light curve that repeats precisely, and can
be modeled by a Fourier series very accurately. The overtone pulsator (SZ Tau, 3.1 d period)
on the other hand shows light curve variation from cycle to cycle which we characterize by
the variations in the Fourier parameters. We present arguments that we are seeing instability
in the pulsation cycle of the overtone pulsator, and that this is also a characteristic of the O −C
curves of overtone pulsators. On the other hand, deviations from cycle to cycle as a function
of pulsation phase follow a similar pattern in both stars, increasing after minimum radius. In
summary, pulsation in the overtone pulsator is less stable than that of the fundamental mode
pulsator at both long and short timescales.
61 citations
Authors
Showing all 1666 results
Name | H-index | Papers | Citations |
---|---|---|---|
Lee Hartmann | 134 | 579 | 57649 |
David W. Latham | 127 | 852 | 67390 |
Chi Lin | 125 | 1313 | 102710 |
William R. Forman | 120 | 800 | 53717 |
Edo Berger | 118 | 578 | 47147 |
Joseph Silk | 108 | 1317 | 58146 |
Jon M. Miller | 107 | 706 | 50126 |
Fabrizio Fiore | 106 | 804 | 43260 |
Randall V. Martin | 105 | 396 | 57917 |
Christopher F. McKee | 103 | 368 | 44919 |
John P. Hughes | 101 | 616 | 36396 |
Wallace L. W. Sargent | 99 | 397 | 30265 |
Bryan Gaensler | 99 | 844 | 39851 |
Alexey Vikhlinin | 99 | 367 | 35822 |
Matthew J. Holman | 99 | 320 | 46577 |