Benedict, G. Fritz, McArthur, Barbara E., Napiwotzki, Ralf, Harrison, Thomas E., Harris, Hugh C., Nelan, Edmund, ...
We present absolute parallaxes and relative proper motions for the central stars of the planetary nebulae NGC 6853 (The Dumbbell), NGC 7293 (The Helix), Abell 31, and DeHt 5. This paper details our...
A Possible Period for the K-Band Brightening Episodes of GX 17+2 (2009)
Bornak, Jillian, McNamara, Bernard J., Harrison, Thomas E., Rupen, Michael, Bandyopadhyay, Reba M., Wachter, Stefanie
The low-mass X-ray binary and Z source GX 17+2 undergoes infrared K-band brightening episodes of at least 3.5 mag. The source of these episodes is not known. Prior published K-band magnitudes and new...
A Possible Period for the K-band Brightening Episodes of GX 17+2 (2009)
Bornak, Jillian, McNamara, Bernard J, Harrison, Thomas E, Rupen, Michael P, Bandyopadhyay, Reba M, Wachter, Stefanie
The low mass X-ray binary and Z source GX 17+2 undergoes infrared K-band brightening episodes of at least 3.5 magnitudes. The source of these episodes is not known. Prior published K-band magnitudes...
Campbell, Ryan K., Harrison, Thomas E., Kafka, Stella
We present phase-resolved low resolution infrared spectra of AM Her and ST LMi, two low-field polars that we observed with SPEX on the IRTF. Optical/NIR lightcurves are also published to help...
GALEX, Optical and IR Light Curves of MQ Dra: UV Excesses at Low Accretion Rates (2008)
Szkody, Paula, Linnell, Albert P., Campbell, Ryan K., Plotkin, Richard M., Harrison, Thomas E., Holtzman, Jon, ...
Ultraviolet light curves constructed from NUV and FUV detectors on GALEX reveal large amplitude variations during the orbital period of the Low Accretion Rate Polar MQ Dra (SDSSJ1553+55). This...
Scuti Stars, Matthew R. Templeton, Thomas E. Harrison
Introduction Mid-far infrared and radio observations of A-F stars are important for constraining the level of mass loss from these stars. It was theorized by Willson, et al (1987) that mass loss...
Bean, Jacob L., McArthur, Barbara E., Benedict, G. Fritz, Harrison, Thomas E., Bizyaev, Dmitry, Nelan, Edmund, ...
We have determined a dynamical mass for the companion to HD 33636 which indicates it is a low-mass star instead of an exoplanet. Our result is based on an analysis of Hubble Space Telescope (HST)...
Benedict, G. Fritz, McArthur, Barbara E., Feast, Michael W., Barnes, Thomas G., Harrison, Thomas E., Patterson, Richard J., ...
(abridged) We present new absolute trigonometric parallaxes and relative proper motions for nine Galactic Cepheid variable stars: l Car, zeta Gem, beta Dor, W Sgr, X Sgr, Y Sgr, FF Aql, T Vul, and RT...
Harrison, Thomas E., Campbell, Ryan K., Howell, Steve B., Cordova, France A., Schwope, Axel D.
We present Spitzer Infrared Spectrograph (IRS) observations of eleven intermediate polars (IPs). Spectra covering the wavelength range from 5.2 to 14 $\mu$m are presented for all eleven objects, and...
The Nature of the Secondary Star in the Black Hole X-Ray Transient V616 Mon (=A0620-00) (2006)
Harrison, Thomas E., Howell, Steve B., Szkody, Paula, Cordova, France A.
We have used NIRSPEC on Keck II to obtain $K$-band spectroscopy of the low mass X-ray binary V616 Mon (= A0620$-$00). V616 Mon is the proto-typical soft x-ray transient containing a black hole...
Szkody, Paula, Harrison, Thomas E., Plotkin, Richard M., Howell, Steve B., Seibert, Mark, Bianchi, Luciana
Low-state optical photometry of EF Eri during an extended low accretion state combined with GALEX near- and far-UV time-resolved photometry reveals a source of UV flux that is much larger than the...
Howell, Steve B., Walter, Frederick M., Harrison, Thomas E., Huber, Mark E., Becker, Robert H., White, Richard L.
EF Eri is a magnetic cataclysmic variable that has been in a low accretion state for the past nine years. Low state optical spectra reveal the underlying Zeeman-split white dwarf absorption lines....
Szkody, Paula, Harrison, Thomas E., Plotkin, Richard M., Howell, Steve B., Seibert, Mark, Bianchi, Luciana
Low state optical photometry of EF Eri during an extended low accretion state combined with GALEX near and far UV time-resolved photometry reveals a source of UV flux that is much larger than the...
Low State, Phase-Resolved IR Spectroscopy of VV Puppis (2005)
Howell, Steve B., Harrison, Thomas E., Campbell, Ryan K., Cordova, France A., Szkody, Paula
We present phase-resolved low resolution $JHK$ and higher resolution $K$-band spectroscopy of the polar VV Pup. All observations were obtained when VV Pup was in a low accretion state having a K...
The optical counterpart to the peculiar X-ray transient XTE J1739-302 (2005)
Negueruela, Ignacio, Smith, David M., Harrison, Thomas E., Torrejon, Jose Miguel
The weak X-ray transient XTE J1739-302, characterized by extremely short outbursts, has recently been identified with a reddened star. Here we present spectroscopy and photometry of the counterpart,...
Why Are The Secondary Stars in Polars So Normal? (2005)
Harrison, Thomas E., Howell, Steve B., Szkody, Paula, Cordova, France A.
We have used NIRSPEC on Keck II to obtain $K$-band spectroscopy of several magnetic cataclysmic variables. These data reveal that the secondary stars in these binary systems have spectra that are...
Phase-Resolved Infrared H- and K-band Spectroscopy of EF Eridani (2004)
Harrison, Thomas E., Howell, Steve B., Szkody, Paula, Homeier, Derek, Johnson, Joni J., Osborne, Heather L.
We present new phase-resolved H and K-band spectroscopy of the ultra-short period magnetic cataclysmic variable EF Eri in its current, prolonged ``low'' state obtained using NIRI on Gemini-North, and...
McArthur, Barbara E., Endl, Michael, Cochran, William D., Benedict, G. Fritz, Fischer, Debra A., Marcy, Geoffrey W., ...
We report the detection of the lowest mass extra-solar planet yet found around a Sun-like star - a planet with an \msini of only 14.21 $\pm$ 2.91 Earth masses in an extremely short period orbit...
Harrison, Thomas E., Osborne, Heather L., Howell, Steve B.
We present moderate resolution (R > 1,800) infrared K-band spectra of twelve long-period (Porb > 6 hr) cataclysmic variables. We detect absorption lines from the photospheres of the secondary stars...
Peculiar abundances in cv secondary stars: revising their Evolutionary history? (2004)
Derek Homeier, Heather L. Osborne, Joni J. Johnson, Steve B. Howell, Thomas E. Harrison
Determining the masses and evolution of cvs through Ellipsoidal variations (2004)
Heather L. Osborne, Joni J. Johnson, Steve B. Howell, Thomas E. Harrison
Keck IR Spectroscopy of WZ Sge: Detection of Molecular Emission from the Accretion Disk (2003)
Howell, Steve B., Harrison, Thomas E., Szkody, Paula
Time-resolved IR spectroscopy of WZ Sge was obtained using NIRSPEC on Keck II. We detect CO and H$_{\rm 2}$ emission from the accretion disk placing WZ Sge into a rarefied class of astronomical...
The origin of cyclic period changes in close binaries: the case of the Algol binary WW Cygni (2002)
Zavala, Robert T., McNamara, Bernard J., Harrison, Thomas E., Galvan, Eduardo, Galvan, Javier, Jarvis, Thomas, ...
Years to decade-long cyclic orbital period changes have been observed in several classes of close binary systems including Algols, W Ursae Majoris and RS Canum Venaticorum systems, and the...
Gelino, Dawn M., Harrison, Thomas E., Orosz, Jerome A.
We have obtained optical and infrared photometry of the soft x-ray transient prototype V616 Mon (A0620-00). From this photometry, we find a spectral type of K4 for the secondary star in the system,...
Gelino, Dawn M., Harrison, Thomas E., McNamara, Bernard J.
We have obtained infrared photometry for the soft x-ray transient GU Mus. We present J and K_s band light curves modeled with WD98, the newest version of the Wilson-Devinney light curve modeling...
Infrared Observations of AR Ursae Majoris: Modeling the Ellipsoidal Variations (2000)
Howell, Steve B., Gelino, Dawn M., Harrison, Thomas E.
We have obtained time-series infrared photometry for the highly magnetic cataclysmic variable AR UMa. Our J and K' band observations occurred during a low state and they show a distinctive...
Measuring the Mass of the Black Hole in GS2000+25 Using IR Ellipsoidal Variations (1999)
Leeber, Dawn M., Harrison, Thomas E., McNamara, Bernard J.
Soft X-ray Transients (SXTs) are binary systems that are believed to consist of a black hole and a normal late type dwarf star which fills its Roche Lobe. We have used GRIM II on the ARC 3.5 meter...
Harrison, Thomas E., McNamara, Bernard J., Szkody, Paula, McAurthur, Barbara J., Benedict, G. F., Klemola, Arnold R., ...
We report astrometric parallaxes for three well known dwarf novae obtained using the Fine Guidance Sensors on the Hubble Space Telescope. We found a parallax for SS Aurigae of Pi = 5.00 +/- 0.64 mas,...