Back to Search
Start Over
M Stars in the TW Hya Association: Stellar X-rays and Disk Dissipation
- Publication Year :
- 2016
- Publisher :
- arXiv, 2016.
-
Abstract
- To investigate the potential connection between the intense X-ray emission from young, low-mass stars and the lifetimes of their circumstellar, planet-forming disks, we have compiled the X-ray luminosities ($L_X$) of M stars in the $\sim$8 Myr-old TW Hya Association (TWA) for which X-ray data are presently available. Our investigation includes analysis of archival Chandra data for the TWA binary systems TWA 8, 9, and 13. Although our study suffers from poor statistics for stars later than M3, we find a trend of decreasing $L_X/L_{bol}$ with decreasing $T_{eff}$ for TWA M stars wherein the earliest-type (M0--M2) stars cluster near $\log{(L_X/L_{bol})} \approx -3.0$ and then $\log{(L_X/L_{bol})}$ decreases, and its distribution broadens, for types M4 and later. The fraction of TWA stars that display evidence for residual primordial disk material also sharply increases in this same (mid-M) spectral type regime. This apparent anticorrelation between the relative X-ray luminosities of low-mass TWA stars and the longevities of their circumstellar disks suggests that primordial disks orbiting early-type M stars in the TWA have dispersed rapidly as a consequence of their persistent large X-ray fluxes. Conversely, the disks orbiting the very lowest-mass pre-MS stars and pre-MS brown dwarfs in the Association may have survived because their X-ray luminosities and, hence, disk photoevaporation rates are very low to begin with, and then further decline relatively early in their pre-MS evolution.<br />Comment: 28 pages, 4 figures; to appear in The Astronomical Journal
- Subjects :
- Physics
stars: formation
010308 nuclear & particles physics
Astronomy
FOS: Physical sciences
Astronomy and Astrophysics
stars: pre-main sequence
Astronomy and Astrophysic
circumstellar matter
01 natural sciences
Exoplanet
Luminosity
Stars
Settore FIS/05 - Astronomia E Astrofisica
Star cluster
Astrophysics - Solar and Stellar Astrophysics
Space and Planetary Science
Planet
0103 physical sciences
planets and satellites: formation
Christian ministry
010303 astronomy & astrophysics
Solar and Stellar Astrophysics (astro-ph.SR)
Subjects
Details
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....74f282b133bd7f1c866b3898105bb8d5
- Full Text :
- https://doi.org/10.48550/arxiv.1603.09307