Philip J. Castro, John E. Gizis, Marc Gagné,
... 3. This object is similar to another TW Hydrae BD member, CD-33 7795B (TWA 5B): both have H-alpha emission, both show no signatures of accretion, and ...
Tópico(s): Astrophysics and Star Formation Studies
2011 - IOP Publishing | The Astrophysical Journal
S. Messina, S. Desidera, M. Turatto, A. C. Lanzafame, E. F. Guinan,
... ages in the range 8-70 Myr: TW Hydrae (~8 Myr), beta Pictoris (~10 Myr), Tucana/Horologium, Columba, Carina (~30 Myr), and AB Doradus (~70 Myr). Additional data on alpha Persei and the Pleiades from the literature is ...
Tópico(s): Astro and Planetary Science
2010 - EDP Sciences | Astronomy and Astrophysics
Adam C. Schneider, Inseok Song, Carl Melis, B. Zuckerman, M. S. Bessell,
... TWA 33" and "TWA 34") of the TW Hydrae Association. Both new TWA members display mid-IR excess emission in the Wide-field Infrared Survey Explorer (WISE) catalog and they show proper motion and youthful spectroscopic characteristics -- namely H\alpha emission, strong lithium absorption, and low surface gravity ...
Tópico(s): Astro and Planetary Science
2012 - IOP Publishing | The Astrophysical Journal
Bhagirathi Dash, Richard P. Metz, Henry J. Huebner, Weston W. Porter, Timothy D. Phillips,
... alpha antiparallel hairpin and the C-terminal mixed alpha/beta fold characteristic of MnSODs and that for HvEC-SOD displayed the characteristic CuZnSOD â-barrel fold. Hydrae subjected to thermal, starvation, metal and oxidative stress ...
Tópico(s): Ion channel regulation and function
2006 - Elsevier BV | Gene
Simon J. Murphy, W. A. Lawson, J. Bento,
... Another may be an outlying member of TW Hydrae but has a velocity similar to that predicted by membership in Octans. We also identify two new lithium-rich members of the neighbouring Scorpius-Centaurus OB Association (Sco-Cen). Both exhibit large 12 and 22 micron excesses and strong, variable H-alpha emission which we attribute to accretion from circumstellar ...
Tópico(s): Astro and Planetary Science
2015 - Oxford University Press | Monthly Notices of the Royal Astronomical Society
Subhanjoy Mohanty, Ray Jayawardhana, Gibor Basri,
... IC 348, R CrA, Upper Sco and TW Hydrae regions, with ages <1 to ~10 Myr. The sample contains 41 BDs (spectral types >= M6.5). We find that: (1) classical T Tauri-like disk-accretion persists in the BD domain down to nearly the deuterium-burning limit; (2) in addition to H-alpha, permitted emission lines of CaII, OI and HeI ...
Tópico(s): Stellar, planetary, and galactic studies
2005 - IOP Publishing | The Astrophysical Journal
... the age of the young moving group TW Hydrae Association, a cohort of a few dozen stars ... we have derived spectral types and measured H(alpha) and lithium equivalent widths. We have also estimated ... a L5 spectral type and measured its H(alpha) equivalent width. Our age estimate for the association, ...
Tópico(s): Astro and Planetary Science
2006 - EDP Sciences | Astronomy and Astrophysics
David J. Wilner, Paul T. P. Ho, J. H. Kastner, Luis F. Rodrı́guez,
The TW Hydrae system is perhaps the closest analog to the early solar nebula. We have used the Very Large Array ... dot in circle yr-1 and viscosity parameter alpha=0.01. The estimates of mass and mass ...
Tópico(s): Astro and Planetary Science
2000 - IOP Publishing | The Astrophysical Journal
M. Flores Soriano, K. G. Strassmeier,
... evolution of the chromospheric activity from the H$\alpha$ and H$\beta$ lines, and the distribution of ... the other. The equivalent width of the H$\alpha$ line from the least active hemisphere increased from ~ ... active hemisphere remained roughly constant at a H$\alpha$ EW of ~1.0 {\AA}. Intense flare activity ... were detected. The line asymmetries of the H$\alpha$ line suggest that one of the flares could ... The comparison between the maps and the H$\alpha$ line as the star rotates reveals the spatial coexistence of chromospheric H$\alpha$ emission and photospheric spots. Our results indicate that ...
Tópico(s): Astro and Planetary Science
2016 - EDP Sciences | Astronomy and Astrophysics
Brendan P. Miller, J. Budaj, Mercedes T. Richards, P. Koubský, Godefridus J. Peters,
... synthetic spectra, and tomography. We analyzed 119 H-alpha spectra of TT Hya, an Algol-type eclipsing ... per year. Doppler tomography of the observed H-alpha profiles revealed a distinct accretion disk. The difference ...
Tópico(s): Astrophysical Phenomena and Observations
2007 - IOP Publishing | The Astrophysical Journal
G. Beccari, Guido De Marchi, N. Panagia, E. Valenti, G. Carraro, M. Romaniello, M. Zoccali, C. Weidner,
... component around the relatively old PSM stars TW Hydrae, 49 Ceti, and HD 95086, support a new ...
Tópico(s): Astro and Planetary Science
2014 - EDP Sciences | Astronomy and Astrophysics
A. Frasca, Zs. Kővári, K. G. Strassmeier, K. Biazzo,
We analyze the Hα spectral variability of the rapidly-rotating K1-dwarf LQ Hya using high-resolution Hα spectra recorded during April-May 2000. Chromospheric parameters were computed from the Hα profile as a function of rotational phase. We find that all these parameters vary in phase, with a higher chromospheric electron density coinciding with the maximum Hα emission. We find a clear rotational modulation of the Hα emission that is better emphasized by subtracting a reference photospheric template ...
Tópico(s): Astro and Planetary Science
2008 - EDP Sciences | Astronomy and Astrophysics
Maria Wöllert, W. Brandner, S. Reffert, Joshua E. Schlieder, M. Mohler-Fischer, R. Köhler, Thomas Henning,
... proposed as a candidate member of the TW Hydrae Association (TWA) which is a young (5-15 ... orbital motion, the proper motion changes to $\mu_\alpha*\cos(\delta) = -137.84 \pm 1.26\,$ mas/ ...
Tópico(s): Astro and Planetary Science
2014 - EDP Sciences | Astronomy and Astrophysics
D. A. Schwartz, G. Fabbiano, R. E. Griffiths, H. Bradt, R. Doxsey, Mark Johnston, U. G. Briel, B. Margon,
... with Ha emission, and the dwarf nova EX Hydrae, respectively. The latter two are only the second ...
Tópico(s): Scientific Measurement and Uncertainty Evaluation
1979 - Institute of Physics | The Astronomical Journal
M. Ishida, K. Mukai, J. P. Osborne,
We have observed the intermediate polar EX Hya with Advanced Satellite for Cosmology and Astrophysics (ASCA), and have clearly detected He-like and H-like K alpha emission lines from Mg to Fe. The intensity ratios of these pairs of lines are not compatible with an isothermal plasma, and a temperature distribution can no longer be parameterized by the conventional two emission component model. We have successfully decomposed iron line emission into thermal plasma component and flourescent component. ...
Tópico(s): Astrophysics and Star Formation Studies
1994 - Oxford University Press | Publications of the Astronomical Society of Japan