1992 NASA Life Support Systems Analysis workshop

The 1992 Life Support Systems Analysis Workshop was sponsored by NASA's Office of Aeronautics and Space Technology (OAST) to integrate the inputs from, disseminate information to, and foster communication among NASA, industry, and academic specialists. The workshop continued discussion and definition of key issues identified in the 1991 workshop, including: (1) modeling and experimental validation; (2) definition of systems analysis evaluation criteria; (3) integration of modeling at multiple levels; and (4) assessment of process control modeling approaches. Through both the 1991 and 1992 workshops, NASA has continued to seek input from industry and university chemical process modeling and analysis experts, and to introduce and apply new systems analysis approaches to life support systems. The workshop included technical presentations, discussions, and interactive planning, with sufficient time allocated for discussion of both technology status and technology development recommendations. Key personnel currently involved with life support technology developments from NASA, industry, and academia provided input to the status and priorities of current and future systems analysis methods and requirements

High Resolution Near-Infrared Spectra of Protostars

We present new high resolution (R = 21,000) near-infrared (2 microns) spectroscopic observations of a sample of Class I and flat-spectrum protostellar objects in the rho Ophiuchi dark cloud. None of the five Class I spectra show CO v = 0 -- 2 absorption features, consistent with high K-band continuum veilings, 4 <= r_k <= 20 and fast stellar rotation, assuming that the underlying protostellar photospheres are of late spectral type, as is suggested by the low luminosities of most of these objects. Two of the flat-spectrum protostellar objects also show no absorption features and are likely to be highly veiled. The remaining two flat-spectrum sources show weak, broad absorptions which are consistent with an origin in quickly rotating (v sin i ~ 50 km / s) late-type stellar photospheres which are also strongly veiled, r_k = 3 - 4. These observations provide further evidence that: 1)-Class I sources are highly veiled at near-infrared wavelengths, confirming previous findings of lower resolution spectroscopic studies; and 2)- flat-spectrum protostars rotate more rapidly than classical T Tauri stars (Class II sources), supporting findings from a recent high resolution spectroscopic study of other flat-spectrum sources in this cloud. In addition our observations are consistent with the high rotation rates derived for two of the Class I protostellar objects in our sample from observations of variable hard X-ray emission obtained with the ASCA satellite. These observations suggest that certain Class I sources can rotate even more rapidly than flat-spectrum protostars, near breakup velocity.Comment: 16 pages including 2 tables and 2 figures (AASTeX 5.x) to be published in The Astronomical Journal July 200

1991 NASA Life Support Systems Analysis workshop

The 1991 Life Support Systems Analysis Workshop was sponsored by NASA Headquarters' Office of Aeronautics and Space Technology (OAST) to foster communication among NASA, industrial, and academic specialists, and to integrate their inputs and disseminate information to them. The overall objective of systems analysis within the Life Support Technology Program of OAST is to identify, guide the development of, and verify designs which will increase the performance of the life support systems on component, subsystem, and system levels for future human space missions. The specific goals of this workshop were to report on the status of systems analysis capabilities, to integrate the chemical processing industry technologies, and to integrate recommendations for future technology developments related to systems analysis for life support systems. The workshop included technical presentations, discussions, and interactive planning, with time allocated for discussion of both technology status and time-phased technology development recommendations. Key personnel from NASA, industry, and academia delivered inputs and presentations on the status and priorities of current and future systems analysis methods and requirements

Spectroscopic Detection of a Stellar-like Photosphere in an Accreting Protostar

We present the first spectrum of a highly veiled, strongly accreting protostar which shows photospheric absorption features and demonstrates the stellar nature of its central core. We find the spectrum of the luminous (L_bol = 10 L_sun) protostellar source, YLW 15, to be stellar-like with numerous atomic and molecular absorption features, indicative of a K5 IV/V spectral type and a continuum veiling r_k = 3.0. Its derived stellar luminosity (3 L_sun) and stellar radius (3.1 R_sun) are consistent with those of a 0.5 M_sun pre-main-sequence star. However, 70% of its bolometric luminosity is due to mass accretion, whose rate we estimate to be 1.6 E-6 M_sun / yr onto the protostellar core. We determine that excess infrared emission produced by the circumstellar accretion disk, the inner infalling envelope, and accretion shocks at the surface of the stellar core of YLW 15 all contribute signifi- cantly to its near-IR continuum veiling. Its projected rotation velocity v sin i = 50 km / s is comparable to those of flat-spectrum protostars but considerably higher than those of classical T Tauri stars in the rho Oph cloud. The protostar may be magnetically coupled to its circumstellar disk at a radius of 2 R_*. It is also plausible that this protostar can shed over half its angular momentum and evolve into a more slowly rotating classical T Tauri star by remaining coupled to its circumstellar disk (at increasing radius) as its accretion rate drops by an order of magnitude during the rapid transition between the Class I and Class II phases of evolution. The spectrum of WL 6 does not show any photospheric absorption features, and we estimate that its continuum veiling is r_k >= 4.6. Together with its low bolometric luminosity (2 L_sun), this dictates that its central core is very low mass, ~0.1 M_sun.Comment: 14 pages including 9 figures (3 figures of 3 panels each, all as separate files). AASTeX LaTex macros version 5.0. To be published in The Astronomical Journal (tentatively Oct 2002

A study of the elements copper through uranium in Sirius A: Contributions from STIS and ground-based spectra

We determine abundances or upper limits for all of the 55 stable elements from copper to uranium for the A1 Vm star Sirius. The purpose of the study is to assemble the most complete picture of elemental abundances with the hope of revealing the chemical history of the brightest star in the sky, apart from the Sun. We also explore the relationship of this hot metallic-line (Am) star to its cooler congeners, as well as the hotter, weakly- or non-magnetic mercury-manganese (HgMn) stars. Our primary observational material consists of {\em Hubble Space Telescope} ($HST$) spectra taken with the Space Telescope Imaging Spectrograph (STIS) in the ASTRAL project. We have also used archival material from the %\citep/{ayr10}. $COPERNICUS$ satellite, and from the $HST$ Goddard High-Resolution Spectrograph (GHRS), as well as ground-based spectra from Furenlid, Westin, Kurucz, Wahlgren, and their coworkers, ESO spectra from the UVESPOP project, and NARVAL spectra retrieved from PolarBase. Our analysis has been primarily by spectral synthesis, and in this work we have had the great advantage of extensive atomic data unavailable to earlier workers. We find most abundances as well as upper limits range from 10 to 100 times above solar values. We see no indication of the huge abundance excesses of 1000 or more that occur among many chemically peculiar (CP) stars of the upper main sequence. The picture of Sirius as a hot Am star is reinforced.Comment: With 6 Figures and 4 Tables; accepted for publication in Ap

Hypersensitivity Vasculitis with Leukocytoclastic Vasculitis Associated with Alpha-1-Proteinase Inhibitor

Prolastin is a commercially available form of alpha-1-antitrypsin (AAT) that is derived from pooled human plasma and used for treatment of severe alpha-1-antitrypsin deficiency (AATD). We describe a patient with AATD who developed presumed hypersensitivity vasculitis (HV) following a Prolastin infusion. Hypersensitivity vasculitis (HV), or cutaneous vasculitis, is characterized by inflammation of the small vessels of the skin with resultant ischemia to the distally supplied areas. To our knowledge, this is the first reported case of presumed hypersensitivity vasculitis following Prolastin infusion