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XMM Use Cases
- Low-mass YSO often have more x-ray
- Differential rotation decays with age and thus does x-ray.
- However other origins e.g. colliding winds possible
- For background info see
- An XMM-Newton-based X-ray survey of pre-main sequence stellar emission in the L1551 star-forming complex Favata et al. 2003A&A...403..187F
- Lx/Lbol is x~2.5 lower for low mass stars while they are actively accreting, maybe inner accretion disc field interacts with stellar magnetic field to mess up corona.
- Non-accreters have log(Lx/Lbol) ~-2 - -3 (Briggs et al. 2004 IAUS219 "Stars as Suns" ASP Conf Series XXX)
- accretion diagnosed by excess [U-V]
- Schulz et al. CHANDRA obs of Orion etc.
- Massive YSO - x-ray dominated by stellar magnetic origin. As ages on MS, wind emission dominates.
- Mag fields anti-correlated with age?
- Are Trapezium stars MS, ZAMS or PMS?
- X-rays from proplyds hard, absorbed and variable - suggesting not due to impact of Trapezium wind, but from small (au-scale/stellar) region.
- AVO application
- Access XMM images in full band (0.2 - 12 keV) and 5 sub-bands in two ways:
- SIA (VOdemo tab) from XMM Archive
- IDHA heirachical tree
- Can correlate x-ray with other diagnostics to investigate age/mass of YSO candidates:
- Can make RGB (0.5-2.0, 2.0-4.5, 4.5-7.5) keV
- Harder emission from YSO implies more absorbed, younger
- Soft, relatively bright emission implies T Tauri star
- No or v. faint soft x-ray from class II-III candidate implies higher mass Herbig AeBe star.
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