Chandra X-Ray Observatory
	(CXC)

Please note that the abstracts refer to the PROPOSED project - which is not necessarily identical to the approved project.
For accurate target information, please check the Observation Catalog.


Joint HST/Chandra Accepted Cycle 14 Targets and Abstracts

Proposal NumberSubject CategoryPI NameTarget NameTotal Chandra TimeTitle
14200978Extra-Solar Planets David EhrenreichGJ 436b60ksProperties and dynamics of the upper atmosphere of the hot- Neptune GJ 436b
14500977Hot StarsOleg KargaltsevCrab PWN10ksMultiwavelength spectra of the fine structure of the Crab
14910976ISM and Circumstellar Matter Yangsen Yao4U 0512-401200ksMultiwavelength Spectroscopy of the Interstellar Medium: O and Ne Abundance ratio

Subject Category: Extra-Solar Planets

Proposal Number: 14200978

Properties and dynamics of the upper atmosphere of the hot- Neptune GJ 436b

PI Name: David Ehrenreich

Atmospheric escape of highly-irradiated exoplanets can be detected as strong absorption in the stellar Lyman-alpha line during planetary transits. The observed evaporation is thought to be driven by absorption of stellar X/EUV radiation. Here we propose to detect atmospheric escape from a hot-Neptune, GJ 436b. We demonstrated with HST/STIS that this star is a bright Lyman-alpha target. Hence, we will use this same instrument to measure the properties of the upper atmosphere of this hot-Neptune, constrain its escape rate, and search for temporal variations in its exosphere. We also propose coordinated Chandra observations of GJ 436bĘs transits to measure the atmospheric escape efficiency factor and test the impact of stellar X-ray variability on the atmospheric properties of the planet.


Subject Category: Hot Stars

Proposal Number: 14500977

Title: Multiwavelength spectra of the fine structure of the Crab

PI Name: Oleg Kargaltsev

Observations with HST and Chandra have resolved the remarkable dynamic PWN structure and advanced the theory of relativistic magnetized outflows in general and pulsar winds in particular. However, contemporaneous, multiwavelength spectra of the prominent PWN features are still lacking. We propose a joint HST-Chandra-EVLA campaign to understand multiwavelength spectral changes across the PWN. Thanks to the brightness of the Crab PWN and superb resolution of all the three observatories, spectral changes can be mapped on ~1 arcsecond scales in a very short time. This program is very efficient, highly synergistic, and will also provide a legacy set of contemporaneous, high-resolution images of the Crab PWN that will serve as a reference for years to come.


Subject Category: ISM and Circumstellar Matter

Proposal Number: 14910976

Title: Multiwavelength Spectroscopy of the Interstellar Medium: O and Ne Abundance ratio

PI Name: Yangsen Yao

The recent downward revision of several light elements has broken the accordance with helioseismological measurements. A much higher Ne/O abundance ratio may solve this problem, but this scenario has not been tested observationally. The interstellar medium (ISM) provides a natural laboratory for testing such a hypothesis. We propose a joint program by requesting COS-HST and LETG-Chandra observations of the low mass X-ray binary 4U 0512-401. The required observations will utilize the high resolving power of the COS to resolve the kinematic velocity components of the ISM absorbers, and then utilize LETG observations to measure column densities of OI, OII, NeI, NeII, NeIII, and HI. The results will enable us to examine whether the Ne/O ratio is substantially higher than that usually adopted.

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