Keivan G. Stassun

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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. ABSTRACT We characterize the star KOI 961, an M dwarf with transit signals(More)
The Chandra Orion Ultradeep Project (COUP) provides the most comprehensive dataset ever acquired on the X-ray emission of pre-main sequence stars. In this paper, we study the nearly 600 X-ray sources that can be reliably identified with optically well characterized T Tauri stars (TTS) in the Orion Nebula Cluster. With a detection limit of L X,min ∼ 10 27.3(More)
The Open University's repository of research publications and other research outputs SDSS-III: massive spectroscopic surveys of the distant universe, the Milky Way, and extra-solar planetary systems Journal Article Eisenstein et al. ABSTRACT Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II), SDSS-III is a program of four spectroscopic(More)
We present the results of a 5 month photometric time-series survey for stellar rotation over a 40 ′ ×40 ′ field centered on the 150 Myr open cluster M35. We report rotation periods for 441 stars within this field and determine their cluster membership and binarity based on a decade-long radial-velocity survey, proper-motion measurements, and multi-band(More)
We present rotation periods for the solar-type primary stars in 13 close (a 5 AU) single-lined spectroscopic binaries with known orbital periods (P) and eccentricities (e). All binaries are members of the open clusters M35 (NGC2168; ∼ 150 Myr) and M34 (NGC1039; ∼ 250 Myr). The binary orbital parameters and the rotation periods of the primary stars were(More)
We have analyzed a number of intense X-ray flares observed in the Chandra Orion Ultradeep Project (COUP), a 13 days observation of the Orion Nebula Cluster (ONC), concentrating on the events with the highest statistics (in terms of photon flux and event duration). Analysis of the flare decay allows to determine the physical parameters of the flaring(More)
We re-analyze all archival Chandra/ACIS observations of the Orion Nebula Cluster (ONC) to study the X-ray properties of a large sample of pre–main-sequence (PMS) stars with optically determined rotation periods. Our goal is to elucidate the origins of X-rays in PMS stars by seeking out connections between the X-rays and the mechanisms most likely driving(More)
Although the environments of star and planet formation are thermodynamically cold, substantial X-ray emission from 10–100 MK plasmas is present. In low-mass pre-main-sequence stars, X-rays are produced by violent magnetic reconnection flares. In high-mass O stars, they are produced by wind shocks on both stellar and parsec scales. The recent Chandra Orion(More)
The Fisk-Vanderbilt Masters-to-Ph.D. Bridge Program is a model for substantially increasing the number of underrepresented minority students earning doctoral degrees in the physical sciences. The program presently leads the nation in master's degrees in physics for African-Americans, and is one of the top ten producers of physics master's degrees among all(More)
We present a database of BV RI time-series photometry of the Orion Nebula Cluster obtained with two ground-based telescopes at different longitudes to provide simultaneous coverage with the 13-d Chandra observation of the cluster. The resulting database of simultaneous optical and X-ray light curves for some 800 pre–main-sequence (PMS) stars represents, by(More)