Search NASA⌕ Search

Engineering topics

Catanzarite, J.

Publications and source records attributed to Catanzarite, J..

16 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Kepler: A Search for Terrestrial Planets - Kepler Data Characterization Handbook

The Kepler Data Characteristics Handbook (KDCH) provides a description of all phenomena identified in the Kepler data throughout the mission, and an explanation for how these characteristics are handled by the final version of the Kepler Data Processing Pipeline (SOC 9.3).The KDCH complements the Kepler Data Release Notes (KDRNs), which document phenomena and processing unique to a data release. The original motivation for this separation into static, explanatory text and a more journalistic set of figures and tables in the KDRN was for the user to become familiar with the Data Characteristics Handbook, then peruse the short Notes for a new quarter, referring back to the Handbook when necessary. With the completion of the Kepler mission and the final Data Release 25, both the KDCH and the DRN encompass the entire Kepler mission, so the distinction between them is in the level of exposition, not the extent of the time interval discussed.

Kepler↗
NASA NTRS2002

Overview of SIM wide angle astrometric system calibration strategies

This paper summarizes two very different strategies envisioned for calibrating the systematic field dependent biases present in the Space Interferometry Mission (SIM) instrument. The Internal Calibration strategy is based on pre-launch measurements combined with a set of on orbit measurements generated by a source internal to the instrument. The External Calibration strategy uses stars as an external source for generating the calibration function. Both approaches demand a significant amount of innovation given that SIM's calibration strategy requires a post-calibration error of 100picometers over a 15 degree field of regard while the uncalibrated instrument introduces 10's-100's of nanometers of error. The calibration strategies are discussed in the context of the Wide Angle Astrometric mode of the instrument, although variations on the Internal Calibration Strategy may be used for doing Narrow Angle Astrometry.

calibration SIM optical modeling↗
NASA NTRS2002

SIM white light on-board processing algorithms

Interferometry in optical astronomy is an important and growing field of astronomical observation. A number of stellar interferometers have come online over the past several years, and several more are due to be operational in the near future. In addition, space based interferometers are also planned missions of NASA's Origins program, including the Space Interferometry Mission (SIM), the focus of the present paper. The fundamental measurement made by each of these interferometers is the white light fringe measurement to determine the optical pathlength delay between the two arms of the interferometer. SIM makes white light measurements with three independent interferometers observing three different objects. Two of these are the "guide" interferometers that observe bright objects (approximately 7th magnitude) to track the rigid body motion of the instrument. The third interferometer, the "science" interferometer, observes the science targets of interest.

interferometry↗
NASA NTRS2002

Overview of SIM external calibration

Like all astrometric instruments, the Space Interferometry Mission (SIM) suffers from field-dependent errors requiring calibration. Diffraction effects in the delay line, polarization rotations on comer cubes, and beam walk across imperfect optics, all contribute to field-distortion that is significantly larger than is acceptable. The bulk of the systematic error is linear across the field - that is, it results in a magnification error. We show that the linear terms are inconsequential to the performance of SIM because they are inseparable from baseline length and orientation errors. One approach to calibrating the higher-order terms is to perform external' calibration; that is, SIM periodically makes differential measurements of a field of bright stars whose positions are not precisely known. We describe the requirements and constraints on the external calibration process and lay the groundwork for a specific procedure detailed in accompanying papers.

Space↗
NASA NTRS2002

Multiperiodicity in the Light Variations of the Beta Cephei Star Beta Crucis

High-resolution spectroscopic observations have led recently to the discovery that the beta Cephei star beta Crucis (Mimosa) is multiperiodic with at least three non-radial pulsation modes. Data obtained by the star tracker of the WIRE satellite have now allowed us to confirm this multiperiodicity in the light variations. A total of 5 million observations covering 17 days was analyzed and the three main periods we find in this work are in perfect agreement with the results derived from the line profile variations. The photometric amplitudes are small (3, 2.7 and 0.6 millimag for the dominant modes), but this is not surprising in view of the mode identifications derived earlier from the line profiles. Additional periods of low-amplitude modes (between 0.2-0.3 mmag) are also derived, including one suggested earlier by the radial velocity data.

Cuypers, J.↗
NASA NTRS2002

Asteroseismology from Space: The Delta Scuti Star Theta(sup 2) Tauri Monitored by the WIRE Satellite

The bright variable star theta(sup 2) Tau was monitored with the star camera on the Wide-Field Infrared Explorer satellite. Twelve independent frequencies were detected down to the 0.5 mmag amplitude level. Their reality was investigated by searching for them using two different algorithms and by some internal checks: both procedures strengthened our confidence in the results. All the frequencies are in the range 10.8-14.6 cd(exp -1). The histogram of the frequency spacings shows that 81% are below 1.8 d; rotation may thus play a role in the mode excitation. The fundamental radial mode is not observed, although it is expected to occur in a region where the noise level is very low (55 mu mag). The rms residual is about two times lower than that usually obtained from successful groundbased multisite campaigns. The comparison of the results of previous campaigns with the new ones establishes the amplitude variability of some modes.

Poretti, E.↗
NASA NTRS2002

Multiperiodicity in the Light Variations of the Beta Cephei Star Beta Crucis

High-resolution spectroscopic observations have led recently to the discovery that the P Cephei star Beta Crucis (Mimosa) is multiperiodic with at least three non-radial pulsation modes. Data obtained by the star tracker of the WIRE satellite have now allowed us to confirm this multiperiodicity in the light variations. A total of five million observations covering 17 days was analyzed and the three main periods we find in this work are in perfect agreement with the results derived from the line profile variations. The photometric amplitudes are small (3, 2.7 and 0.6 millimag for the dominant modes), but this is not surprising in view of the mode identifications derived earlier from the line profiles. Additional periods of low-amplitude modes (between 0.2-0.3 mmag) are also derived, including one suggested earlier by the radial velocity data.

Cuypers, J.↗
NASA NTRS2002

Asteroseismology from Space: The Delta Scuti Star Theta(sup 2) Tauri Monitored by the WIRE Satellite

The bright variable star (theta)(sup 2) Tau was monitored with the star camera on the Wide-Field Infrared Explorer satellite. Twelve independent frequencies were detected down to the 0.5 mmag amplitude level. Their reality was investigated by searching for them using two different algorithms and by some internal checks: both procedures strengthened our confidence in the results. All the frequencies are in the range 10.8 - 14.6 cd(exp -1). The histogram of the frequency spacings shows that 81% are below 1.8 d; rotation may thus play a role in the mode excitation. The fundamental radial mode is not observed, although it is expected to occur in a region where the noise level is very low (55 (micro)mag). The rms (root mean square) residual is about two times lower than that usually obtained from successful groundbased multisite campaigns. The comparison of the results of previous campaigns with the new ones establishes the amplitude variability of some modes.

Poretti, E.↗