Wei-Chun Jao

Cool Subdwarf Investigations II: Multiplicity (2009)

Jao, Wei-Chun, Mason, Brian D., Hartkopf, William I, Henry, Todd J., Ramos, Stephanie N.

Cool subdwarfs of types K and M are the fainter counterparts of cool main sequence dwarfs that dominate the Galactic population. In this paper we present the results of an optical speckle survey of...

The Solar Neighborhood. XXI. Parallax Results from the CTIOPI 0.9m Program: 20 New Members of the 25 Parsec White Dwarf Sample (2009)

Subasavage, John P., Jao, Wei-Chun, Henry, Todd J., Bergeron, P., Dufour, P., Ianna, Philip A., ...

We present accurate trigonometric parallaxes for 20 new members of the 25 pc white dwarf sample as part of the DENSE project (Discovery and Evalution of Nearby Stellar Embers,...

Ultracool Subdwarfs: The Halo Population Down to the Substellar Limit (2008)

Burgasser, Adam J., Lepine, Sebastien, Lodieu, Nicolas, Scholz, Ralf-Dieter, Delorme, Phillippe, Jao, Wei-Chun, ...

Ultracool subdwarfs are low luminosity, late-type M and L dwarfs that exhibit spectroscopic indications of subsolar metallicity and halo kinematics. Their recent discovery and ongoing investigation...

Cool Subdwarf Investigations (CSI) I: New Thoughts for the Spectral Types of K and M Subdwarfs (2008)

Jao, Wei-Chun, Henry, Todd J., Beaulieu, Thomas D., Subasavage, John P.

Using new spectra of 88 K and M-type subdwarfs, we consider novel methods for assigning their spectral types and take steps toward developing a comprehensive spectral sequence for subdwarf types K3.0...

Angular Diameters of the G Subdwarf $\mu$ Cassiopeiae A and the K Dwarfs $\sigma$ Draconis and HR 511 from Interferometric Measurements with the CHARA Array (2008)

Boyajian, Tabetha S., McAlister, Harold A., Baines, Ellyn K., Gies, Douglas R., Henry, Todd, Jao, Wei-Chun, ...

Using the longest baselines of the CHARA Array, we have measured the angular diameter of the G5 V subdwarf $\mu$ Cas A, the first such determination for a halo population star. We compare this result...

The Trigonometric Parallax of the Brown Dwarf Planetary System 2MASSW J1207334-393254 (2007)

Gizis, John E., Jao, Wei-Chun, Subasavage, John P., Henry, Todd J.

We have measured a trigonometric parallax to the young brown dwarf 2MASSW J1207334-393254. The distance [54.0 (+3.2,-2.8) pc] and space motion confirm membership in the TW Hydrae Association. The...

The Solar Neighborhood. XVIII. Discovery of new proper motion stars with 0.40 arcsec yr^-1 > mu >= 0.18 arcsec yr^-1 between declinations -90 degrees and -47 degrees (2007)

Finch, Charlie T., Henry, Todd J., Subasavage, John P., Jao, Wei-Chun, Hambly, Nigel C.

We report 1606 new proper motion systems in the southern sky (declinations -90 degrees to -47 degrees with 0.40 arcsec yr^-1 > mu >= 0.18 yr^-1. This effort is a continuation of the...

The Solar Neighborhood XVII: Parallax Results from the CTIOPI 0.9m Program -- Twenty New Members of the RECONS 10 Parsec Sample (2006)

Henry, Todd J., Jao, Wei-Chun, Subasavage, John P., Beaulieu, Thomas D., Ianna, Philip A., Costa, Edgardo, ...

Astrometric measurements for 25 red dwarf systems are presented, including the first definitive trigonometric parallaxes for 20 systems within 10 pc of the Sun, the horizon of the RECONS sample. The...

Two Suns in The Sky: Stellar Multiplicity in Exoplanet Systems (2006)

Raghavan, Deepak, Henry, Todd J., Mason, Brian D., Subasavage, John P., Jao, Wei-Chun, Beaulieu, Thom D., ...

We present results of a reconnaissance for stellar companions to all 131 radial-velocity-detected candidate extrasolar planetary systems known as of July 1, 2005. CPM companions were investigated...

Ages of White Dwarf-Red Subdwarf Systems (2005)

Monteiro, Hektor, Jao, Wei-Chun, Henry, Todd, Subasavage, John, Beaulieu, Thom

We provide the first age estimates for two recently discovered white dwarf-red subdwarf systems, LHS 193AB and LHS 300AB. These unusual systems provide a new opportunity for linking the reliable age...

The Solar Neighborhood XV: Discovery of New High Proper Motion Stars with mu >= 0.4"/yr between Declinations -47 degrees and 00 degrees (2005)

Subasavage, John P., Henry, Todd J., Hambly, Nigel C., Brown, Misty A., Jao, Wei-Chun, Finch, Charlie T.

We report the discovery of 152 new high proper motion systems (mu >= 0.4"/yr) in the southern sky (Declination = -47 degrees to 00 degrees) brighter than UKST plate R_{59F} =16.5 via our...

The Solar Neighborhood XIII: Parallax Results from the CTIOPI 0.9-m Program -- Stars with mu >= 1"/year (MOTION Sample) (2005)

Jao, Wei-Chun, Henry, Todd J., Subasavage, John P., Brown, Misty A., Ianna, Philip A., Bartlett, Jennifer L., ...

We present the first set of definitive trigonometric parallaxes and proper motions from the Cerro Tololo Inter-American Observatory Parallax Investigation (CTIOPI). Full astrometric reductions for...

The Solar Neighbourhood XI: The trigonometric parallax of SCR 1845--6357 (2004)

Deacon, Niall R., Hambly, Nigel C., Henry, Todd J., Subasavage, John P., Brown, Misty A., Jao, Wei-Chun

We present a trigonometric parallax for the nearby star SCR1845--6357, an extremely red high proper motion object discovered by Hambly et al. (2004) and identified via accurate photoelectric...

The Solar Neighborhood XII: Discovery of New High Proper Motion Stars with 1.0"/yr > mu >= 0.4"/yr between Declinations -90 degrees and -47 degrees (2004)

Subasavage, John P., Henry, Todd J., Hambly, Nigel C., Brown, Misty A., Jao, Wei-Chun

We report the discovery of 141 new high proper motion systems (1.0"/yr > mu >= 0.4"/yr) in the southern sky (Declination = -90 degrees to -47 degrees) brighter than UKST plate R_{59F} = 16.5 via our...

The Solar Neighborhood X: New Nearby Stars in the Southern Sky and Accurate Photometric Distance Estimates for Red Dwarfs (2004)

Henry, Todd J., Subasavage, John P., Brown, Misty A., Beaulieu, Thomas D., Jao, Wei-Chun, Hambly, Nigel C.

Photometric VRI and spectroscopic (6000-9500 A) observations of high proper motion stars discovered during the first phase of the SuperCOSMOS RECONS (SCR) search are used to estimate accurate...