Engineering topics

Kleinmann, S. G.

Publications and source records attributed to Kleinmann, S. G..

At least 19 records

NASA NTRS1994

The Two Micron All Sky Survey

The Two Micron All Sky Survey (2MASS) will provide a uniform survey of the entire sky at three near-infrared wavebands: J(lambda(sub eff) = 1.25 micrometers), H(lambda(sub eff) = 1.65 micrometers), and K(sub s)(lambda(sub eff) = 2.16 micrometers). A major goal of the survey is to probe large scale structures in the Milky Way and in the Local Universe, exploiting the relatively high transparency of the interstellar medium in the near-infrared, and the high near-infrared luminosities of evolved low- and intermediate-mass stars. A sensitive overview of the near-infrared sky is also an essential next step to maximize the gains achievable with infrared array technology. Our assessment of the astrophysical questions that might be addressed with these new arrays is currently limited by the very bright flux limit of the only preceding large scale near-infrared sky survey, the Two Micron Sky Survey carried out at Caltech in the late 1960's. Near-infrared instruments based on the new array technology have already obtained spectra of objects 1 million times fainter than the limit of the TMSS! This paper summarizes the essential parameters of the 2MASS project and the rationale behind those choices, and gives an overview of results obtained with a prototype camera that has been in operation since May 1992. We conclude with a list of expected data products and a statement of the data release policy.

Kleinmann, S. G.↗

NASA NTRS1994

The Two Micron All Sky Survey

This paper describes the design, expectations, and prototyping of a new all sky survey, called 2MASS (Two Micron All Sky Survey) to be carried out with the new generation of infrared array detectors.

Kleinmann, S. G.↗

NASA NTRS1993

Long-period oxygen-rich optical Miras in the solar neighborhood

The spatial distribution of the oxygen-rich Miras with periods longer than 400 days in the neighborhood of the sun were determined using available survey and the K-band period luminosity relationship. It is found that the exponential scale height of these stars is near 240 pc. There is a marked contrast between the Mira population at about 1 kpc from the Galactic center where there are nearly as many long-period oxygen-rich Miras as intermediate-period oxygen-rich Miras. It is hypothesized that, at about 1 kpc from the Galactic center, the main sequence stars with masses larger than 1 solar mass have higher metallicities than main-sequence stars with the same masses in the solar neighborhood. In the solar neighborhood such main sequence stars become carbon-rich on the AGB and in the region near the Galactic center they become long-period oxygen-rich Miras.

Jura, M.↗

NASA NTRS1993

IRAS variables as galactic structure tracers - Classification of the bright variables

The characteristics of the 'bright infrared variables' (BIRVs), a sample consisting of the 300 brightest stars in the IRAS Point Source Catalog with IRAS variability index VAR of 98 or greater, are investigated with the purpose of establishing which of IRAS variables are AGB stars (e.g., oxygen-rich Miras and carbon stars, as was assumed by Weinberg (1992)). Results of the analysis of optical, infrared, and microwave spectroscopy of these stars indicate that, out of 88 stars in the BIRV sample identified with cataloged variables, 86 can be classified as Miras. Results of a similar analysis performed for a color-selected sample of stars, using the color limits employed by Habing (1988) to select AGB stars, showed that, out of 52 percent of classified stars, 38 percent are non-AGB stars, including H II regions, planetary nebulae, supergiants, and young stellar objects, indicating that studies using color-selected samples are subject to misinterpretation.

Allen, L. E.↗

NASA NTRS1992

Oxygen-rich semiregular and irregular variables

All the known oxygen-rich semiregulars and irregulars of spectral classes K and M with the absolute value of B not greater than 30 deg, Delta(m) not less than 0.5 mag, and, for the semiregulars, periods in the range of 50 to 400 d are compiled. On the basis of their distributions on the sky and their brightnesses in the K band at 2.2 microns, it is argued that the semiregulars with a period of 300-400 d appear to belong to the same population as the 'thin disk' Miras in the same period range and have an exponential scale height from the Galactic plane of about 250 pc. The semiregulars with a period range of 200 to 300 d belong to the population of the 'thick disk' Miras with an exponential scale height from the Galactic plane of about 500 pc. On the basis of the similarities of their space distributions and the presence of Tc in their atmospheres, and using the pulsational mode calculations by Ostlie and Cox (1986), it is suggested that the semiregulars with a period range of 100-150 d are first and second overtone pulsations of the same population of AGB stars as the Miras in their fundamental pulsational mode with periods longer than 300 d.

Jura, M.↗

NASA NTRS1992

Short- and intermediate-period oxygen-rich Miras

Available IR photometry and the period-IR luminosity relationship are used to analyze a nearly complete sample of oxygen-rich Miras at Galactic latitudes with /b/ greater than 30 deg. In agreement with previous kinematic studies, a marked difference is found in the spatial distributions between the stars with periods less than and those with periods greater than 300 d. For stars with periods in the range 300-400 d, the exponential scale height from the Galactic plane is close to 240 pc, the projected surface density is about 100/sq kpc, and the local space density is about 210/cu kpc. The progenitors of the Miras with periods greater than 300 d appear to be disk dwarfs with typical main-sequence masses of between 1.0 and 1.2 solar masses. The masses of the main-sequence progenitors of the short-period Miras are 1.1 solar masses or less. The duration of the Mira phase for the intermediate-period stars is estimated to be about 20,000 yr, somewhat longer than other recent estimates. Both short- and intermediate-period oxygen-rich Miras characteristically lose mass at about 10 exp -7 solar mass/yr.

Jura, M.↗

NASA NTRS1992

2MASS - The 2 Micron All Sky Survey

This paper describes a new sky survey to be carried out in three wavebands, J(1.25 m), H(1.65 m), and K(2.2 m). The limiting sensitivity of the survey, 10 sigma detection of point sources with K not greater than 14 mag, coupled with its all-sky coverage, were selected primarily to support studies of the large-scale structure of the Milky Way and the Local Universe. The survey requires construction of a pair of observing facilities, one each for the Northern and Southern Hemispheres. Operations are scheduled to begin in 1995. The data will begin becoming publicly available soon thereafter.

Kleinmann, S. G.↗

NASA NTRS1990

Very dusty carbon-rich asymptotic giant branch stars between about 1 and about 2.5 kiloparsecs from the sun

Combining IRAS, Two Micron Sky Survey, and ground-based optical and radio data, carbon-rich asymptotic giant branch (AGB) stars within about 2.5 kpc of the sun, in the zone delta between 81 deg and -33 deg, that are typically losing about 0.00001 solar mass/yr were identified. Distances are derived assuming a luminosity of 10,000 solar luminosities; there are 126 stars in this zone that are between about 1 and about 2.5 kpc from the sun. By including the 29 very dusty carbon stars that were previously identified to lie within 1 kpc of the sun, it is found that there is no Galactocentric gradient in the space distribution of the very dusty carbon stars, in contrast to the general population of stars which is more concentrated toward the Galactic center. The surface density of very dusty carbon stars in the Galactic plane is about 10/kpc sq. In the solar neighborhood, carbon stars return roughly half of the material from all AGB stars into the interstellar medium; in the outer Galaxy they dominate the mass return, while they are probably not so important in the inner Galaxy.

Jura, M.↗

NASA NTRS1990

(C-12)O emission from the envelopes of cool stars in the solar neighborhood

Results are presented on observations of the CO J = 1-0 line emission from all M giants, S stars, and C stars listed in the Two-Micron Sky Survey having strong FIR emission and lying north of delta = -10 deg. The data from this survey and other data for C and S stars show that the line profiles of these stars look like flattened parabolas and have roughly the same shape for different stars. In contrast, the shapes of the spectral lines from giant M stars are diverse, ranging from triangular to spiked and asymmetric, suggesting that the envelopes of M stars have complex kinematics and structure. The outflow velocities inferred from the line profiles of the stars surveyed span a range of more than an order of magnitude, with the velocities of C stars correlating with IR color.

Margulis, M.↗

NASA NTRS1990

Mass-losing M supergiants in the solar neighborhood

A list of the 21 mass-losing red supergiants (20 M type, one G type; L greater than 100,000 solar luminosities) within 2.5 kpc of the sun is compiled. These supergiants are highly evolved descendants of main-sequence stars with initial masses larger than 20 solar masses. The surface density is between about 1 and 2/sq kpc. As found previously, these stars are much less concentrated toward the Galactic center than W-R stars, which are also highly evolved massive stars. Although with considerable uncertainty, it is estimated that the mass return by the M supergiants is somewhere between 0.00001 and 0.00003 solar mass/sq kpc yr. In the hemisphere facing the Galactic center there is much less mass loss from M supergiants than from W-R stars, but, in the anticenter direction, the M supergiants return more mass than do the W-R stars. The duration of the M supergiant phase appears to be between 200,000 and 400,000 yr. During this phase, a star of initially at least 20 solar masses returns perhaps 3-10 solar masses into the interstellar medium.

Jura, M.↗

NASA NTRS1990

The probable dust formation episode around Rho Cassiopeiae

By comparing IRAS photometry with previous 10-micron data, it appears that dust formed in the circumstellar envelope around the supergiant G star, Rho Cas, sometime between 1973 and 1983. This dust formation may have been the consequence of the gas outflowing and cooling from the intense mass outburst of 1946. In 1983, the dust was detected at a temperature between 600 and 800 K at a distance between 10 to the 15th cm and 4 x 10 to the 15th cm from the star. While the dust-to-gas ratio in the circumstellar envelope may be as low as 0.00001 and thus much lower than in other mass-losing stars, the luminosity of Rho Cas is sufficiently large that radiation pressure on this dust might be dynamically important in helping to drive mass loss.

Jura, M.↗

NASA NTRS1989

Dust-enshrouded asymptotic giant branch stars in the solar neighborhood

Using available infrared catalogs, an inventory is taken of the AGB star losing large amounts of mass within about 1 kpc of the sun. A surface density of these stars is estimated of about 25/sq kpc projected onto the plane of the Galaxy. Of these stars, about one-half are oxygen-rich while the other half are carbon-rich. The total mass-loss rate from AGB stars into the interstellar medium is probably between 3 and 6 x 10 to the -4th solar mass/sq kpc/yr. Within the uncertainties, this is in reasonable agreement with an estimated net loss rate of about 8 x 10 to the -4th solar mass/sq kpc/yr for main-sequence stars with initial masses between 1 and 5 solar masses as they evolve to white dwarfs. However, it is possible that there are important sources of mass loss which have not yet been identified. In the solar neighborhood, about one-half of all about 1.2 solar mass main-sequence stars spend greater than 30,000 yr in a carbon-star phase where they lose 1-2 x 10 to the -5th solar mass/yr and then become white dwarfs with about 0.7 solar mass.

Jura, M.↗

NASA NTRS1989

A faint, dust-enshrouded carbon star at high galactic latitude

During the initial phase of a program to search for substellar candidates at high galactic in the IRAS Serendipitous Survey Catalog, one source, SSC 08546+1732, was found to have no optical couterpart on the Palomar Observatory Sky Survey plates. Ground-based positional, photometric, and spectroscopic observations have identified this source as a heavily dust-enshrouded carbon star, similar to those found in the Galactic plane. The high latitude and relative faintness of this source imply that it lies at a distance of 20-50 kpc, and is 10-30 kpc out of the plane of the Galaxy. SSC 08546+1732 and one other distant obscured carbon star found in the IRAS Point Source Catalog (Low 1987; Beichman et al. 1989) represent the first examples of such objects found in the Galactic halo. These stars may either have evolved from Population I precursors ejected from the disk, or they may be the first obscured Population II halo carbon stars to be observed. A survey for other distant enshrouded carbon stars in the IRAS Faint Source Cattalog should help to elucidate the nature of this new population.

Cutri, Roc M.↗

NASA NTRS1989

High-luminosity carbon stars in the galactic anticenter

K-band magnitudes of 211 carbon stars in the Galactic anticenter are presented. The surface density, brightness range, and observed colors of stars in the sample are discussed. It is suggested that the K-band extinction gradient in the Galactic plane near l = 180 deg is between 0.15 and 0.3/kpc. In contrast to the total density of stars, it is found that the density of high-luminosity carbon stars does not decrease in the anticenter region out to at least 3 kpc from the sun. It is proposed that this is due to the fact that lower metallicity stars spend more time as carbon stars compared to stars of solar metallicity. Also, it is shown that the average mass-loss rates from high-luminosity carbon stars in the anticenter direction appear to be lower by a factor of 1.7 than those for carbon stars in the solar neighborhood.

Jura, M.↗

NASA NTRS1989

The spatial, temporal, and photometric properties of AGB stars

Results are presented from analyses of carbon, S type, and mass-losing M stars in the Two Micron Sky Survey (Neugebauer and Leighton, 1969). IRAS data are used to determine the range of IR colors and to estimate the mass loss rates for each class. The Low Resolution Spectrometer characterizations for asymptotic giant branch stars in the survey are given. The prospects for future deep IR surveys are discussed.

Kleinmann, S. G.↗

NASA NTRS1988

The properties and environment of the giant, infrared-luminous galaxy IRAS 09104 + 4109

IRAS 09104 + 4109 is the most luminous object yet discovered by means of the IRAS survey. It is identified with a cD galaxy having a strong emission-line spectrum at a redshift of 0.442 and emits 6 x 10 to the 12th solar luminosities/sq h, 99 percent of which emerges at infrared wavelengths. One component of a double radio source is coincident with the center of the galaxy. The high luminosity of this source may be related to an interaction with one or more members of the rich cluster in which it lies. There is a secondary peak in the emission-line image of the galaxy. Emission lines from both regions are broad but narrower than those characteristic of the only other objects known to have such high luminosities, such as Seyfert 1's and QSOs. It is suggested that the strong infrared excess of IRAS 09104 + 4109 is produced by dust obscuring a broad line region.

Kleinmann, S. G.↗

NASA NTRS1987

A flux-limited sample of Galactic carbon stars

Published observational data (including IRAS observations) for a flux-limited sample of 215 Galactic carbon stars (CSs) selected from the 2-micron sky survey of Neugebauer and Leighton (1969) are compiled in extensive tables and graphs and analyzed statistically. The sample is found to penetrate a volume of radius 1.5 kpc, and the local CS space density and surface density are calculated as log rho0 (per cu kpc) = 2.0 + or - 0.4 and log N (per sq kpc) = 1.6 + or - 0.2, respectively. The total Galactic mass-return rate from these CSs is estimated as 0.013 solar mass/yr, implying a time scale of 0.1-1 Myr for the CS evolutionary phase and a mass of 1.2-1.6 solar mass for the (probably F-type) main-seqence progenitors of CSs.

Claussen, M. J.↗

NASA NTRS1987

A study of a flux-limited sample of IRAS galaxies

Redshift data and accurate four-color infrared photometry are presented for a complete IRAS sample of galaxies brighter than 2 Jy at 60 microns. A simple power law provides a good fit to the distribution for luminosities from 10 to the 10th to 10 to the 12th solar. There is no indication of an exponential dropoff in the luminosity function at high energies. A flattening of the luminosity function occurs at L less than 10 to the 20th solar. The highest luminosity galaxies typically are found in multiple, possibly interacting, systems and exhibit marginally narrower infrared spectral energy distributions than the isolated spirals which predominate at low luminosities. Infrared-bright galaxies come from a different population than the majority of optically bright galaxies. In particular, galaxies of low blue luminosity are not strong infrared emitters.

Smith, Beverly J.↗