Keivan G. Stassun

Eclipsing Binary Stars as Tests of Stellar Evolutionary Models and Stellar Ages (2009)

Stassun, Keivan G., Hebb, Leslie, Lopez-Morales, Mercedes, Prsa, Andrej

Eclipsing binary stars provide highly accurate measurements of the fundamental physical properties of stars. They therefore serve as stringent tests of the predictions of evolutionary models upon...

Fundamental Properties of Low-Mass Stars and Brown Dwarfs (2008)

Liu, Michael C., Stassun, Keivan G., Allard, France, Blake, Cullen H., Bonnefoy, M., Cody, Ann Marie, ...

Precise measurements of the fundamental properties of low-mass stars and brown dwarfs are key to understanding the physics underlying their formation and evolution. While there has been great...

A Survey for a Coeval, Comoving Group Associated with HD 141569 (2008)

Aarnio, Alicia N., Weinberger, Alycia J., Stassun, Keivan G., Mamajek, Eric E., James, David J.

We present results of a search for a young stellar moving group associated with the star HD 141569, a nearby, isolated Herbig AeBe primary member of a 5+/-3 Myr-old triple star system on the...

Surprising dissimilarities in a newly formed pair of 'identical twin' stars (2008)

Stassun, Keivan G., Mathieu, Robert D., Cargile, Phillip A., Aarnio, Alicia N., Stempels, Eric, Geller, Aaron

The mass and chemical composition of a star are the primary determinants of its basic physical properties--radius, temperature, luminosity--and how those properties evolve with time. Thus, two stars...

Stellar Rotation in M35: Mass-Period Relations, Spin-Down Rates, and Gyrochronology (2008)

Meibom, Søren, Mathieu, Robert D., Stassun, Keivan G.

We present the results of a 5 month photometric time-series survey for stellar rotation over a 40'x40' field on the 150 Myr open cluster M35. We report rotation periods for 441 stars and determine...

The Evolution of Galaxies on Cosmological Timescales ASP Conference Series, Vol. (2007)

Theta Beckman And, Keivan G. Stassun

. We review the salient observational properties of DQ Tau, with an emphasis on the photometric and spectroscopic time-variability of the system. We summarize the evidence for this variability being...

m Test of Disk-Regulated Angular Momentum Among Low-Mass Pre-Main-Sequence Stars (2007)

Keivan G. Stassun

. We summarize the results of our recent work testing the hypothesis of disk-regulated angular momentum among low-mass PMS stars. Contrary to some previous studies, we find no connection between slow...

Periodic Accretion from a Circumbinary Disk in the Young Binary UZ Tau E (2007)

Jensen, Eric L. N., Dhital, Saurav, Stassun, Keivan G., Patience, Jenny, Herbst, William, Walter, Frederick M., ...

Close pre-main-sequence binary stars are expected to clear central holes in their protoplanetary disks, but the extent to which material can flow from the circumbinary disk across the gap onto the...

The Monitor project: JW 380 -- a 0.26, 0.15 Msol pre main sequence eclipsing binary in the Orion Nebula Cluster (2007)

Irwin, Jonathan, Aigrain, Suzanne, Hodgkin, Simon, Stassun, Keivan G., Hebb, Leslie, Irwin, Mike, ...

We report the discovery of a low-mass (0.26 +/- 0.02, 0.15 +/- 0.01 Msol) pre-main-sequence eclipsing binary with a 5.3 day orbital period. JW 380 was detected as part of a high-cadence time-resolved...

A Surprising Reversal of Temperatures in the Brown-Dwarf Eclipsing Binary 2MASS J05352184-0546085 (2007)

Stassun, Keivan G., Mathieu, Robert D., Valenti, Jeff A.

The newly discovered brown-dwarf eclipsing binary 2MASS J05352184-0546085 provides a unique laboratory for testing the predictions of theoretical models of brown-dwarf formation and evolution. The...

Periodic accretion from a circumbinary disk in the young binary UZ Tau E (2007)

Jensen, Eric L. N., Dhital, Saurav, Stassun, Keivan G., Patience, Jenny, Herbst, William, Walter, Frederick M., ...

Close pre-main-sequence binary stars are expected to clear central holes in their protoplanetary disks, but the extent to which material can flow from the circumbinary disk across the gap onto the...

An Observational Study of Tidal Synchronization in Solar-Type Binary Stars in the Open Clusters M35 and M34 (2006)

Meibom, Soren, Mathieu, Robert D., Stassun, Keivan G.

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...

A Simultaneous Optical and X-ray Variability Study of the Orion Nebula Cluster. I. Incidence of Time-Correlated X-ray/Optical Variations (2006)

Stassun, Keivan G., Berg, M. Van Den, Feigelson, Eric, Flaccomio, Ettore

We present a database of $BVRI$ 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...

Opening the Treasure Chest: A Newborn Star Cluster Emerges from its Dust Pillar in Carina (2004)

Smith, Nathan, Stassun, Keivan G., Bally, John

We present detailed observations of the Treasure Chest, a compact nebula at the head of a dust pillar in the southern Carina nebula. This object is of interest because it is an example of a dense...

X-ray Properties of Pre--Main-Sequence Stars in the Orion Nebula Cluster with Known Rotation Periods (2004)

Stassun, Keivan G., Ardila, David R., Barsony, Mary, Basri, Gibor, Mathieu, Robert D.

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...

Dynamical Mass Constraints on Low-Mass Pre-Main-Sequence Stellar Evolutionary Tracks: An Eclipsing Binary in Orion with a 1.0 Msun Primary and an 0.7 Msun Secondary (2003)

Stassun, Keivan G., Mathieu, Robert D., Vaz, Luiz Paulo R., Stroud, Nicholas, Vrba, Frederick J.

We report the discovery of a double-lined, spectroscopic, eclipsing binary in the Orion star-forming region. We analyze the system spectroscopically and photometrically to empirically determine...

Angular Momentum Evolution of Young Stars: Toward a Synthesis of Observations, Theory, and Modeling (2003)

Stassun, Keivan G., Terndrup, Donald

The aim of this AAS Topical Session was to update the community on the current state of knowledge about the angular momentum evolution of young stars. For newcomers to the subject, the session was...

A 10-micron Search for Inner-Truncated Disks Among Pre-Main-Sequence Stars With Photometric Rotation Periods (2000)

Stassun, Keivan G., Mathieu, Robert D., Vrba, Frederick J., Mazeh, Tsevi, Henden, Arne

We use mid-IR (primarily 10 $\mu$m) photometry as a diagnostic for the presence of disks with inner cavities among 32 pre-main sequence stars in Orion and Taurus-Auriga for which rotation periods are...

Dynamical Mass Constraints on Low-Mass Pre-Main-Sequence Stellar Evolutionary Tracks: An Eclipsing Binary in Orion with a 1.0 M(solar) Primary and a 0.7 M(solar) Secondary (1998)

Stassun, Keivan G., Mathieu, Robert D., Vaz, Luiz Paulo, Stroud, Nicholas, Vrba, Frederick J.

We report the discovery of a double-lined, spectroscopic, eclipsing binary in the Orion star-forming region. We analyze the system spectroscopically and photometrically to empirically determine...

Dynamical Mass Constraints on Low-Mass Pre-Main-Sequence Stellar Evolutionary Tracks: An Eclipsing Binary in Orion With a 1.0 M Primary and a 0.7 M Secondary (1998)

Stassun, Keivan G., Mathieu, Robert D., Vaz, Luiz P., Stroud, Nicholas, Vrba, Frederick J.

We report the discovery of a double-lined, spectroscopic, eclipsing binary in the Orion star-forming region. We analyze the system spectroscopically and photometrically to empirically determine...

Magnetic Accretion and Photopolarimetric Variability in Classical T Tauri Stars (1998)

Stassun, Keivan G., Wood, Kenneth

We employ a Monte Carlo radiation transfer code to investigate the multi- wavelength photopolarimetric variability arising from a spotted T Tauri star surrounded by a dusty circumstellar disk. Our...