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Proposal Number: 10200053

Title: Summing Flares from EV Lac

PI Name: Claude Canizares

We propose to study the spectral and temporal behavior of flares from the active M-dwarf EV Lac. We will apply three powerful techniques: high-resolution spectroscopic diagnostics to infer flaring loop conditions (temperature, density, dynamics); measurement of flare scale heights from Fe K fluorescence; and state-of-the-art hydrodynamic flare models. The high rate of short flares, the X-ray signature of high density, and the evidence for opacity in X-ray resonance lines make EV Lac an ideal target. A deep flare exposure obtained by summing short events will provide one of the best high-resolution spectra possible for constraining physical models of M-dwarf coronae and flares with detail which can only be achieved through high resolution X-ray spectroscopy.

Proposal Number: 10200070

Title: Revealing the Origin of Hard X-rays in the Remarkable O4-O4 Binary Star System in M17: GTO component

PI Name: Gordon Garmire

The central massive stars in the closest Galactic Giant HII Region M17 are a pair of O4 stars separated by $1.8^{\prime\prime}$. A Chandra Large Project has revealed that both of these O4 stars are extraordinary X-ray sources, showing hard spectra and rapid variability typical of the luminous blue variable $\eta$ Carinae but almost unknown for normal O stars. Using He-like lines resolved by the HETG, we will diagnose whether this remarkable X-ray emission comes from magnetically-channeled wind shocks in single stars or from colliding-wind binaries; if the latter is the case, this pair of early O stars is really a system of four massive stars and constrains models of massive star formation. This is the GTO component of a combined GO/GTO observation (GO PI Marc Gagn\'e).

Proposal Number: 10200077

Title: G29.96-0.02: The enigma of ultra-compact HII regions

PI Name: Gordon Garmire

Young massive stars have strong stellar winds which sweep up and clear their environment. This is a key factor in stopping the star formation process and disrupting their nascent molecular clouds. We propose Chandra observations of the prototypical ultracompact HII (UCHII) region, G29.96-0.02. The proposed observations will provide direct evidence for this wind-cloud interaction. This target with its cometary morphology, low obscuration, and well-studied flow pattern in the surrounding gas, is optimal for X-ray study of the shocked wind plasma. Measuring the X-ray luminosity, spectrum and morphology of G29.96-0.02 will provide critical quantitative insights into the complex astrophysics of UCHIIs which cannot be acquired at long wavelengths.

Proposal Number: 10200079

Title: Search for triggered star formation in the type A bright rimmed cloud 34

PI Name: Gordon Garmire

Bright rimmed clouds (BRCs) near OB stars are excellent laboratories for the study of triggered star formation (TSF) due to the radiation driven implosion (RDI) mechanism. Type A BRCs are clouds at their earliest evolutionary stages and, according to the current theoretical modeling, are not expected to exhibit RDI TSF yet. Employing the Chandra's ability to effectively discern young stellar populations from unrelated old field objects we propose to observe the nearby Type A bright rimmed cloud BRC 34 and test predictions of RDI modelling. BRC 34 will also complement our large GO project on BRCs with the aim to study the RDI star formation efficiency in the Galaxy.

Proposal Number: 10200110

Title: Search for X-ray emission from magnetic chemically peculiar roAp stars

PI Name: Beate Stelzer

Whether intermediate-mass stars can generate X-ray emission is a long-standing problem. A shallow convective envelope is present, but in constrast to late-type dynamo-active stars their magnetic fields are geometrically simple and stable. Commonly any observed X-ray emission from intermediate-mass stars is ascribed to unresolved late-type companions. The rapidly osciallating Ap stars (roAp) are a class of cool, pulsating, chemically peculiar magnetic stars that are known to be single. Therefore, they are prime targets for the search for coronae in the presence of large-scale organized fields. For an explanation of the recent evidence of Promethium, all isotopes of which decay within two decades, flares seem to be the most plausible production mechanism.

Proposal Number: 10200113

Title: Imaging X-Ray Microjets from T Tauri Stars

PI Name: Manuel Guedel

Although many classical T Tauri stars (CTTS) drive bipolar jets, very little is known about the high-energy aspects of these outflows. Recently, two X-ray jets have been discovered from the microjet-driving T Tauri star DG Tau. Both jets are very soft X-ray sources and coincide with the optically visible, much cooler atomic jets. Although faint X-ray sources have also been identified for a few protostellar Herbig-Haro flows, CTTS offer the advantage of an unobscured view down to the star. A spectral anomaly reported for several microjet-driving CTTS (the presence of a strong, constant soft component) suggests that X-ray jets may be common in these objects. We aim at verifying this hypothesis. X-ray jets are potentially important for disk ionization, heating, and chemical processing.

Proposal Number: 10200170

Title: G333.6-0.2: An Embedded Giant HII Region in a Proto-OB Association

PI Name: Leisa Townsley

High-resolution X-ray observations of young massive stars and their surrounding clusters are yielding new insights into the star formation process. We wish to study many facets of massive star formation with a 60-ks ACIS-I observation of G333.6-0.2, a nearby Giant HII Region (GHR) formed very recently, along with two other very young GHRs, in the giant molecular cloud (GMC) G333. We will study embedded massive stars, their surrounding compact cluster of pre-main sequence stars, and the wider context of star formation and GMC evolution in G333, which may be an OB association in the making. We expect to identify hundreds of cluster members and perhaps diffuse X-rays tracing wind-shocked plasma filling G333.6-0.2's large-scale bipolar bubble.

Proposal Number: 10200216

Title: X-ray emission from the magnetic star alpha ^2 Canum Venaticorum ?

PI Name: J rgen Schmitt

We propose a 15 ksec pilot study with Chandra ACIS-S of the visual binary system alpha^2 CVn (= HR~4915 and HR~4914). With an angular separation of $\sim$ 21.3 arcsec this system can be easily resolved with {\it Chandra}. X-ray emission from alpha^2 CVn has been detected with the Einstein Observatory IPC and in the ROSAT RASS data, however, the angular resolution of these data is insufficient to attribute the detected X-ray emission to the F0 component HR~4914 or the A0spe component HR~4915. Since HR~4915 has a measured magnetic field of a few kG, the correct attribution of the detected X-ray emission has far reaching consequences. With the proposed 15 ksec ACIS-S pilot study at the binary HR~4914/4915 we can provide the feasibility of a possible grating observation.

Proposal Number: 10200260

Title: Activity and Rotation in the Zero Age Main Sequence cluster h Per

PI Name: Giuseppina Micela

We will explore the relation between the X-ray luminosity and rotational period in the young open cluster h Per. The age of this cluster (13 Myr) is crucial for the subsequent evolution of the stellar activity and rotation, being at the transition between the PMS and the ZAMS, when a star has reached its maximum rotational velocity. At that age both fast and slow rotators may co-exist, each group having dynamos and coronae following different regimes. h Per with its age and richness is an ideal target for these studies, hosting a very rich sample of coeval stars. We will also take advantage of the rotational periods recently derived with the program Monitor that is able to determine also relatively long rotational periods, allowing us to study at the same time slow and fast rotators.

Proposal Number: 10200267

Title: Berkeley 87: A Young Cluster Embedded in a Supersonic Wolf-Rayet Wind

PI Name: Stephen Skinner

The young open cluster Berkeley 87 in Cygnus (age 1 - 2 Myr; d = 950 kpc) is the only galactic cluster known to harbor a rare oxygen-type Wolf-Rayet star (WR 142). This WO-type star is in a highly-evolved pre-supernova state and its supersonic wind (v = 5500 km/s) is producing dissipative shock waves, as traced by diffuse optical CIV emission. Berk 87 shows clear signs of high-mass star formation including OH masers and compact HII regions. We propose to observe Berk 87 with ACIS-I. This observation will test theories of X-ray production in massive stars and determine if diffuse X-rays from the shocked WR wind are present.

Proposal Number: 10200270

Title: Unusual X-ray Emission from the Rapidly Accreting Young Star FU Orionis

PI Name: Stephen Skinner

FU Orionis objects are a class of very young low-mass stars that have undergone dramatic optical outbursts attributed to an increase in the disk accretion rate onto the star. The intense energy release from these outbursts will vaporize solid material in the terrestrial planet zone and may thus profoundly influence planet formation. We propose to observe the prototype of the class, FU Ori, with ACIS. It is rapidly accreting, has a powerful wind, and is known to have an unusual double absorption X-ray spectrum from a previous XMM observation. Chandra will provide the higher spatial resolution image and improved CCD spectrum needed to clarify the source morphology and origin of the unusual X-ray emission.

Proposal Number: 10200277

Title: ToO Studies with CXO of Pre-Main Sequence Stars Undergoing Optical Outbursts

PI Name: David Weintraub

Dramatic optical outbursts, which signal the onset of rapid and dramatic accretion onto pre-main sequence stars through their disks, cannot be predicted; however, our previous CXO campaign to study the outburst source V1647 Ori demonstrates that studies of such stars made with CXO beginning immediately after outburst can dramatically increase our knowledge about how and why such stars undergo outbursts and accrete mass. We therefore propose a ToO campaign to observe any such star discovered during Cycle 10. We will use ACIS-I to carry out three imaging spectroscopy observations of 20 ks, 20 ks, and 30 ks duration and spaced by intervals of three months, beginning immediately after discovery and continuing through the end of Cycle 10.

Proposal Number: 10200283

Title: IM Lup comes to age: A turnover from accretion to coronae?

PI Name: Hans Guenther

We propose to obtain a Chandra/HETGS spectrum of IM Lup with an exposure of 150 ks. IM Lup is the only known X-ray bright transition object between the classical T Tauri star phase and the weak-lined T Tauri phase. IM Lup shows an IR excess, but its Halpha equivalent width is small, indicating very low accretion rates. The Chandra spectrum will provide important information on the accretion process during the last stages of disk dispersal and therefore the latest possible time for planet growth. We will study the abundance pattern, trace the plasma density in He-like triplets, enhance the observational findings with accretion shock simulations and relate our results to the long-standing problem of disk dispersal and angular momentum evolution in young stars.

Proposal Number: 10200304

Title: The Cycles of Alpha Centauri

PI Name: Thomas Ayres

Alpha Centauri (G2V + K1V) is the nearest system of Sun-like stars; the primary long regarded a solar twin. The binary has been a popular target for previous X-ray missions, although the shrinking orbit now is resolvable only by Chandra. The 25 year X-ray record has revealed striking long term changes in the Alpha Cen coronae, including a deep X-ray minimum of the primary spotted by XMM in 2004-05. A recent LETGS pointing showed that the G star had become quite deficient in >2 MK emissions, but the softer 1 MK spectrum was little changed. Two additional 10 ks HRC-I snapshots in 2009 will continue this remarkable coronal narrative. We also propose key HST FUV spectra of the pair, to constrain emission measures and probe subcoronal dynamics.

Proposal Number: 10200353

Title: Using a Cool B Supergiant to Probe the Deepest X-Ray Emitting Layers of a Dense Stellar Wind

PI Name: Wayne Waldron

We are requesting a 234 ks HETGS observation of the early B supergiant Kappa Ori (B0.5Ia). Among the OB supergiants, Kappa Ori is one of the brightest, but it has not been observed at high spectral resolution. The wind properties of this star as compared to other OB stars will allow us to probe stellar wind distributed X-ray source models from a different perspective and allow us to address the serious issues pertaining to the origin of OB stellar X-ray emission. Models suggest that all f/i derived radii will be distributed at much deeper wind depths than previously determined allowing us to study the X-ray emission properties near the base of the wind. In addition, the first direct measurement of an OB stellar X-ray electron density may be possible.

Proposal Number: 10200414

Title: Collisionless plasma dynamics in WR140 near the 2009 eclipse and periastron

PI Name: Andrew Pollock

In January 2009, the two most extraordinary high-mass colliding-wind binary systems, eta Car and WR140, will both go through the periastron passages of their respective 5.5 and 7.9 year orbits. The preceding weeks are the most favorable for observing the rapid rise to X-ray maximum and learning fundamental lessons about shocks, hot plasmas and mass-loss in the upper HR diagram. Two HETGS spectra of WR140 before periastron and one after will capture its response to the changing physical conditions that follow the well-defined orbital geometry, offering unique information about the dynamics, dissipation and relaxation of collisionless shocks. The proposals on WR140 and eta Car will take advantage of opportunities for X-ray specroscopy that might nt arise again.

Proposal Number: 10200468

Title: Exploring the Stable Coronae of LP349-25 through X-ray and Radio Emission

PI Name: Rachel Osten

The observed correlation between X-ray and radio luminosities for active stars suggests a common coronal energy reservoir from which both processes (particle acceleration for radio emission and plasma heating for X-ray emission) draw. There is a discrepancy of four orders of magnitude in L_X/L_R for very low mass stars compared to active stars, but radio variability from a different emission mechanism may complicate the interpretation. We propose to obtain X-ray and radio observations of a radio-bright close binary, LP349-25, to explore the L_X/L_R relationship for this object with apparently constant radio emission.

Proposal Number: 10200496

Title: Anomalous Adara: The Spatial and Spectral Properties of Extended X-Ray Emission

PI Name: david huenemoerder

We propose to obtain a 10ks ACIS image and spectrum of Adara (epsilon CMa) to characterize an unusual and unexplained spatially extended emission feature in this astrophysically important object. This supposedly non-variable B2 II star shows extended emission in the LETGS zero order and in the spatial dimension of the dispersed spectrum. The LETGS spectrum shows an unusual and broad (10 A) excess centered on 30 A (0.4 keV). The spectral excess was not present in XMM/RGS spectra taken 5 years earlier. Since Adara is noted for its absence of variability, its very low line-of-sight column density, and high EUV flux, it is considered to be a standard for B2 supergiant atmospheric and wind studies. Something has changed. ACIS data are necessary to understand this unprecedented feature.

Proposal Number: 10200509

Title: Testing the Colliding Wind Paradigm: X-rays from the Wolf-Rayet Binary System WR 147

PI Name: Svetozar Zhekov

We propose a deep HETG exposure of the Wolf-Rayet binary system WR 147. The excellent gratings and zero-order data will be used to put tight constraints on the validity of the colliding stellar wind (CSW) mechanism assumed responsible for the X-rays from this object. The detection of broad emission lines with profiles and centroids in agreement with synthetic colliding wind spectra, along with confirmation of the spatially extended X-ray emission reported from the previous short HRC-I exposure, would support the colliding wind picture. On the other hand, narrow (or unresolved) unshifted emission lines would require an interpretation other than CSW. Thus, this study will be the most rigorous test of the CSW paradigm in a WN+OB binary so far.

Proposal Number: 10200574

Title: V2129 Oph: a close look at a CTTS

PI Name: Ettore Flaccomio

We propose to obtain a high resolution X-ray spectrum of the CTT star V2129 Oph in the \rho Ophiuchi star forming cloud. The 200 ks Chandra observation is part of a larger program that includes optical Doppler and Zeeman-Doppler mapping of the stellar photosphere and magnetic field and a simultaneous monitoring of accretion signatures. V2129 Oph is one of the two CTTS for which a magnetogram has been published. Our primary objective is to derive the differential emission measure and the density of the cool plasma at the accretion shock, directly testing the prediction of a published coronal and accretion model, revised with new maps of the magnetic field.

Proposal Number: 10200596

Title: X-RAY AND FUV PHOTO-IONIZATION/-EXCITATION OF TRANSITIONAL DISKS AROUND THE PMS STARS HD135344B and Lk Halpha 330

PI Name: Alexander Brown

Transitional disks have transformed most of the dust and gas in their inner regions into planetesimals or larger solid bodies. They are a rare, short-lived phase of PMS disk evolution and provide important physical insights and modeling constraints on disk and protoplanetary system evolution. We propose to observe two intermediate mass stars with transitional disks, HD135344B and Lk Halpha 330, using ACIS-S on Chandra and the COS FUV spectrograph on HST. We will use these spectra to determine the coronal, transition region, and upper chromospheric emission measure distribution, covering temperatures from 10,000 K to 10 MK, and then calculate the full X-ray/EUV/FUV radiation field for use in modeling its photoexcitation/photoionization effects on the disk structure.

Proposal Number: 10200618

Title: Testing Shock Dynamics in Eta Carinae with HETGS After the 2009 Periastron Passage

PI Name: Michael Corcoran

We propose 2 HETGS observation after the X-ray minimum/periastron passage of Eta Car in Jan. 2009. These observations will take place just after the end of the "high absorption" interval, and just before the wind-blown "bubble" around the companion star breaks through the wind of Eta Car. The X-ray line profiles will be used with previously awarded HETGS observations before the minimum and synthetic line profile models and 3-D wind models and compared to the variations during the 2003.5 minimum to constrain fundamental properties of the flow like the size of the emitting region.

Proposal Number: 10200738

Title: Evolution of Young Stars in the Large Massive Cluster Cep OB3b

PI Name: Thomas Allen

We propose deep ASIC-I imaging of the CepOB3b cluster, a large (> 1000 member), 5 Myr old cluster, 700 pc from the Sun. Spitzer observations have mapped the full extent of CepOB3b, showing two distinct sub-clusters. We will target each sub-clusters to identify the young stars without disks and determine the X-ray properties of the stars. These observations will probe the properties of a young cluster and its constituent stars at a poorly studied evolutionary age, thereby complementing the COUP survey of the 2 Myr old Orion Nebula Cluster. We will study the dynamical evolution of clusters emerging from their parental clouds, the evolution of stellar coronae, the affect of circumstellar disks on the X-ray emission, and the role of X-rays in creating inner holes in disks.

Proposal Number: 10200757

Title: The true nature of HD 110432: the most extreme gamma Cas analog

PI Name: Jose Torrejon

We propose to use the high resolution capabilities of Chandra gratings to study the nature of the Be/X-ray source 1H1249-637=HD 110432, the most extreme of the known gamma Cas analogs. Two hypotheses have been put forward to explain the origin of the X-ray emission in these objects: a) accretion onto a compact object and b) emission from the star+disk interaction through stellar magnetic fields. Both of these challenge profoundly our current understanding of the structure of massive stars and/or how binary systems evolve. HD110432 displays extreme conditions within its class: the hottest plasma (> 20 keV), the hardest spectrum, an enormous circumstellar disk and a close to edge-on inclination.

Proposal Number: 10200787

Title: The Origin of Hard X-rays in M17's Remarkable O4-O4 Binary

PI Name: Marc Gagne

At 2 kpc M17 is the nearest giant HII region, with 10,000 stars younger than 1 Myr and a prominent X-ray champagne flow. At the heart of M17 are CEN 1A and 1B, a visual pair of O4 stars separated by only 1.8". A long series of ACIS observations show that each O4 star is a very hard time variable X-ray source. We suggest that one or both O4 stars are themselves colliding wind shock binaries or, alternatively, that one or both have strong magnetic fields. We propose to obtain time-resolved, spatially resolved HEG/MEG spectra of both stars to measure He-like line ratios and line profiles to directly test these two models. This roll-constrained 150-ks GO proposal is tied to a 25-ks GTO proposal (PI: Garmire) for the same target.

Proposal Number: 10200804

Title: Constraining the Effects of High Energy Photons on Proto-Planetary Disk Chemistry and Evolution

PI Name: Gregory Herczeg

We propose to conduct a multi-wavelength monitoring campaign of two classical T Tauri stars (TW Hya and GM Aur) that possess transitional disks, produce variable [Ne II] emission, generate substantial X-ray emission, and are still actively accreting. Leveraging the variable nature of X-rays, [Ne II] emission, and the mass accretion rates of these sources, we will search for a correlations in these data to provide the first direct observational evidence of the role X-rays and EUV photons play in driving disk chemistry and the evolution of proto-planetary disks. We request three independent observations of each source over the next year supported by ground-based observations with the mid-IR spectrograph MICHELLE on Gemini North and the R-C optical spectrograph on SMARTS at CTIO.

Proposal Number: 10200840

Title: CORONAL AND TRANSITION REGION HEATING DUE TO MAGNETIC ACTIVITY ON METAL-POOR DWARF STARS

PI Name: Alexander Brown

How does low metallicity affect the heating and resultant temperature structure of the chromospheres/transition regions/coronae of old solar-like dwarf stars? Our ACIS-S observations of 7 Gyr old Arcturus Moving Group (AMG) dwarfs show very little conventional coronal (> 1 MK) plasma and suggest that these stars have insufficient magnetic energy input to power a solar-like corona. However, they do have chomospheres and transition regions similar to the minimum activity Quiet Sun. It this typical or an aberration of the AMG? We propose a 35 ksec ACIS-S observation of the nearest (9.2 pc), truely metal-poor ([Fe/H] = -1.4) dwarf star that is known to have definite magnetic dynamo activity (activity cycles, active region modulation) -- HD103095 -- to investigate this question further.

Proposal Number: 10200900

Title: Direct X-ray measurements of the expansion of planetary nebulae

PI Name: Young YU

We propose the first direct measurements of the proper motion of X-ray-emitting regions within planetary nebulae (PNs), via new Chandra observations of the PNs NGC 7027 and BD +303639. In the case of NGC 7027, measurement of the speeds of X-ray-emitting jets will provide a straightforward and unique test of simple jet shock models and unparalleled insight into the evident rapid structural evolution of this seminal young PN. In the case of BD+303639, confirmation of our tentative result that its X-ray ``hot bubble'' is expanding at about 200 km/s would represent a milestone in our understanding of the wind interactions that shape PNs.

Proposal Number: 10200901

Title: X-ray Monitoring of Eta Car in 2009: Unveiling the Deep X-ray Minimum

PI Name: Kenji Hamaguchi

X-ray observations of Eta Car near the 2003 periastron passage confirmed that the X-ray emission primarily arises from wind-wind collision (WWC) in a binary system, but raised fundamental questions about the cause of the 3 month-long minimum. The current promising mechanism is either an eclipse of the WWC plasma by primary winds or a fading of the WWC activity due to an increase in gas density, which relates to the mass loss mechanism which influences the evolution of massive stars. To test these scenarios, we propose key, targeted high signal-to noise observations of the faintest phase missed in 2003 to track both the flux and spectral variations. We request joint observations of Eta Car with Chandra and XMM-Newton around the 2009 minimum.

Proposal Number: 10200921

Title: AO-10 Calibration Observations to Monitor the Spatial Variations in the HRC-I Gain

PI Name: CXC Calibration

We continue to monitor the small scale gain variations in the HRC-I with raster scans of ArLac.

Proposal Number: 10200922

Title: AO-10 Calibration Observations of Capella

PI Name: CXC Calibration

We continue to monitor the dispersion relation of the gratings with annual observations of Capella.

Proposal Number: 10200923

Title: AO-10 Calibration Observations to Monitor the Spatial Variations in the HRC-S Gain

PI Name: CXC Calibration

We continue to monitor the small scale gain variations in the HRC-S with raster scans of ArLac.

Proposal Number: 10200926

Title: AO-10 Calibration Observations of HZ43

PI Name: CXC Calibration

We continue to monitor the low energy response of the HRC with observations of HZ43.

Proposal Number: 10200930

Title: AO-10 Measurements of the optical/UV Transmission of the HRC Filters.

PI Name: CXC Calibration

We continue to monitor the optical/UV transmission of the HRC filters with observations of Vega.

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