Hdl Handle:
http://hdl.handle.net/10150/282758
Title:
INFRARED SPECKLE INTERFEROMETRY
Author:
Howell, Robert Richard
Issue Date:
1980
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Since 1975 McCarthy and Low have conducted a program of Michelson spatial interferometry at infrared wavelengths, measuring a large number of evolved stars and protostellar objects. This dissertation discusses the development of an infrared speckle interferometer which was used to extend those observations. This instrument uses a modified version of the technique pioneered by Sibille, Chelli, and Lena. The secondary mirror is used to scan the image across a narrow slit. Each scan is fourier transformed, and the modulii squared of many such transforms are coadded. Both the object of interest and a point source are observed. The square root of the ratio of their power spectra is the visibility as defined by Michelson. This system was assembled for the most part with existing equipment and the design should be readily adaptable to other observatories. Initial tests were made with the 154 cm telescope of the University of Arizona since it had a preexisting mechanism for scanning the secondary. However most of the observations were carried out with the University's 229 cm telescope. A new linear servo was added to the existing hard-stop chopper for this telescope's f/45 secondary. Three detector systems were used to provide wavelength coverage from 2 to 12 microns. An N₂ cooled InSb and a He cooled bolometer were available from the Michelson program. In addition a high sensitivity He cooled InSb detector from the Steward Observatory FTS was used. Slits with an angular size of λ/2D, where D is the telescope diameter were placed at the focal plane in the dewar. The narrow slit results in diffraction losses when used with conventional dewar optics. The loss could be eliminated with optics optimized for this application. However even with the loss, a large number of objects could be observed. Test results at 2 microns were obtained for a double star, the asteroids Vesta and Ceres, and the Galilean satellites Ganymede and Callisto, The protostellar objects W3 IRS 5, S140, and Mon R2 IRS 3 were resolved. The separation, orientation, and relative brightness of the two components IRS 5 were measured at 5 microns. The separation is 1.26" ±0.06 and the position angle is 37° ±5. The brightness ratio is approximately 0.59. S140 and Mon R2 IRS 3 were observed at 2 microns. S140 shows some indication of an extended region of greater than 1" contributing half the flux. IRS 3 has a size of approximately 1" but the data is too noisy for an exact fit. Upper size limits were determined for BN, GL 490, GL 2591, and NGC 2264 IRS. A large number of evolved stars were observed. The size of the shell around Alpha Ori was found to be ∼4" at 11 microns. Observations were obtained for IRC + 10216 at 2, 5, 8, and 11 microns which further define the asymmetrical shape of this object. Observations were also obtained for VY CMa. Upper size limits were established for Omicron Ceti, IRC + 10011, RX Boo, R Hyd, W Hyd, and CIT 6.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Interferometers.; Speckle metrology.; Infrared astronomy.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Planetary Sciences
Degree Grantor:
University of Arizona
Advisor:
Low, Frank

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleINFRARED SPECKLE INTERFEROMETRYen_US
dc.creatorHowell, Robert Richarden_US
dc.contributor.authorHowell, Robert Richarden_US
dc.date.issued1980en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractSince 1975 McCarthy and Low have conducted a program of Michelson spatial interferometry at infrared wavelengths, measuring a large number of evolved stars and protostellar objects. This dissertation discusses the development of an infrared speckle interferometer which was used to extend those observations. This instrument uses a modified version of the technique pioneered by Sibille, Chelli, and Lena. The secondary mirror is used to scan the image across a narrow slit. Each scan is fourier transformed, and the modulii squared of many such transforms are coadded. Both the object of interest and a point source are observed. The square root of the ratio of their power spectra is the visibility as defined by Michelson. This system was assembled for the most part with existing equipment and the design should be readily adaptable to other observatories. Initial tests were made with the 154 cm telescope of the University of Arizona since it had a preexisting mechanism for scanning the secondary. However most of the observations were carried out with the University's 229 cm telescope. A new linear servo was added to the existing hard-stop chopper for this telescope's f/45 secondary. Three detector systems were used to provide wavelength coverage from 2 to 12 microns. An N₂ cooled InSb and a He cooled bolometer were available from the Michelson program. In addition a high sensitivity He cooled InSb detector from the Steward Observatory FTS was used. Slits with an angular size of λ/2D, where D is the telescope diameter were placed at the focal plane in the dewar. The narrow slit results in diffraction losses when used with conventional dewar optics. The loss could be eliminated with optics optimized for this application. However even with the loss, a large number of objects could be observed. Test results at 2 microns were obtained for a double star, the asteroids Vesta and Ceres, and the Galilean satellites Ganymede and Callisto, The protostellar objects W3 IRS 5, S140, and Mon R2 IRS 3 were resolved. The separation, orientation, and relative brightness of the two components IRS 5 were measured at 5 microns. The separation is 1.26" ±0.06 and the position angle is 37° ±5. The brightness ratio is approximately 0.59. S140 and Mon R2 IRS 3 were observed at 2 microns. S140 shows some indication of an extended region of greater than 1" contributing half the flux. IRS 3 has a size of approximately 1" but the data is too noisy for an exact fit. Upper size limits were determined for BN, GL 490, GL 2591, and NGC 2264 IRS. A large number of evolved stars were observed. The size of the shell around Alpha Ori was found to be ∼4" at 11 microns. Observations were obtained for IRC + 10216 at 2, 5, 8, and 11 microns which further define the asymmetrical shape of this object. Observations were also obtained for VY CMa. Upper size limits were established for Omicron Ceti, IRC + 10011, RX Boo, R Hyd, W Hyd, and CIT 6.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectInterferometers.en_US
dc.subjectSpeckle metrology.en_US
dc.subjectInfrared astronomy.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePlanetary Sciencesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorLow, Franken_US
dc.identifier.proquest8104292en_US
dc.identifier.oclc7617981en_US
dc.identifier.bibrecord.b13469447en_US
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