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2017

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Articles 391 - 395 of 395

Full-Text Articles in Astrophysics and Astronomy

The Basic Physics Of The Binary Black Hole Merger Gw150914, B. P. Abbott, K. Gill, B. Hughey, J. Pratt, M. J. Szczepańczyk, M. Zanolin, Et Al. Jan 2017

The Basic Physics Of The Binary Black Hole Merger Gw150914, B. P. Abbott, K. Gill, B. Hughey, J. Pratt, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

The first direct gravitational-wave detection was made by the Advanced Laser Interferometer Gravitational Wave Observatory on September 14, 2015. The GW150914 signal was strong enough to be apparent, without using any waveform model, in the filtered detector strain data. Here, features of the signal visible in the data are analyzed using concepts from Newtonian physics and general relativity, accessible to anyone with a general physics background. The simple analysis presented here is consistent with the fully general-relativistic analyses published elsewhere, in showing that the signal was produced by the inspiral and subsequent merger of two black holes. The black holes …

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Gyrochronology Of Wide Binaries In The Kepler K2 Fields, Alexander Stone-Martinez, Gustavo Villarroel, Patrice Majewski, Tomomi Otani, Terry Oswalt, Andrew Mcnaughton Jan 2017

Gyrochronology Of Wide Binaries In The Kepler K2 Fields, Alexander Stone-Martinez, Gustavo Villarroel, Patrice Majewski, Tomomi Otani, Terry Oswalt, Andrew Mcnaughton

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Gyrochronology is the method of determining a stars age based on its rotation period and mass. A cool main sequence star loses it's angular momentum as it ages, so the rotation rate slows down. Gyrochronology has been tested on star clusters in previous studies and now we are applying the theory to binary stars. Components of a binary should be the same age, so Gyrochronology should return the same age for both stars in binary systems. We examined the rotation periods for 290 wide binary main sequence stars in the Kepler K2 fields. These observations are part of a continuing …

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O-C Analysis Of The Pulsating Subdwarf B Star Pg 1219 + 534, Tomomi Otani, Terry Oswalt, Alexander Stone-Martinez, Dana Singh, Kenneth Sampson, Aliyah Khan, Austin Seepersad, Caila Deabreu, Adam Moss, Claudia Morello Jan 2017

O-C Analysis Of The Pulsating Subdwarf B Star Pg 1219 + 534, Tomomi Otani, Terry Oswalt, Alexander Stone-Martinez, Dana Singh, Kenneth Sampson, Aliyah Khan, Austin Seepersad, Caila Deabreu, Adam Moss, Claudia Morello

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PG 1219 + 534 (KY Uma) is a subdwarf B pulsating star with multiple periodicities between 120 – 175 s. PG 1219 + 534 was monitored for 90 hours during 2010-1 and 2016 using the 0.9 m SARA-KP telescope at Kitt Peak National Observatory (KPNO) in Arizona and the 0.8m Ortega telescope at Florida Institute of Technology in Melbourne, Florida. So far, the most promising theory for the origin of subdwarf B (sdB) stars is that they result from binary mass transfer near the Helium Flash stage of evolution. The observations of PG 1219 + 534 reported here are part …

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Gyrochronology Of Wide Binaries In The Kepler K2 Campaign 5 Field, Terry D. Oswalt, Derek Buzasi, Tomomi Otani Jan 2017

Gyrochronology Of Wide Binaries In The Kepler K2 Campaign 5 Field, Terry D. Oswalt, Derek Buzasi, Tomomi Otani

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We are determining rotation periods for an ensemble of over 100 wide non-interacting binary stars in the K2 Campaign 5 field that contain two main sequence dwarfs, as well as a smaller sample containing at least one white dwarf component. Observations of such coeval pairs provide the basis for our new investigation of rotation-based age determinations. Such “gyrochronology” ages can achieve a precision that exceeds most other current method of stellar age determination. Here we present a status report on our analysis of the light curves extracted from the K2 Campaign 5 field.

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Testing The Stellar Rotation Vs. Age Paradigm Using Wide Binaries In The Kepler & K2 Fields, T. D. Oswalt, T. Otani, A. Stone-Martinez, P. Majewski, D. Buzasi Jan 2017

Testing The Stellar Rotation Vs. Age Paradigm Using Wide Binaries In The Kepler & K2 Fields, T. D. Oswalt, T. Otani, A. Stone-Martinez, P. Majewski, D. Buzasi

Publications

Essential to understanding the history of the Galaxy’s stellar populations, ages are among the most difficult to measure properties of stars. Accurate stellar ages would provide key leverage on problems ranging from the habitability of exoplanets to the Galaxy’s chemical evolution and age. Gyrochronology, the empirical relation between rotation and age, is believed to be among the best current methods of stellar age determination. Using several hundred wide non-interacting binaries identified in the Kepler mission “K2” extended mission fields we are testing this paradigm. Such wide pairs afford a unique opportunity to unravel and calibrate the effects of mass, rotation, …

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