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Articles 1 - 11 of 11
Full-Text Articles in Physical Sciences and Mathematics
Separated Fringe Packet Observations With The Chara Array. Iii. The Very High-Eccentricity Binary Hr 7345, Chris D. Farrington, Francis C. Fekel, Gail Schaefer, Theo A. Ten Brummelaar
Separated Fringe Packet Observations With The Chara Array. Iii. The Very High-Eccentricity Binary Hr 7345, Chris D. Farrington, Francis C. Fekel, Gail Schaefer, Theo A. Ten Brummelaar
Information Systems and Engineering Management Research Publications
After an 11-year observing campaign, we present the combined visual–spectroscopic orbit of the formerly unremarkable bright star HR 7345 (HD 181655, HIP 94981, GJ 754.2). Using the Separated Fringe Packet method with the CHARA Array, we were able to determine a difficult-to-complete orbital period of 331.609 ± 0.004 days. The 11-month period causes the system to be hidden from interferometric view behind the Sun for three years at a time. Due to the high-eccentricity orbit of about 90% of a year, after 2018 January the periastron phase will not be observable again until late 2021. Hindered by its extremely high …
Infrared Spectroscopy Of Symbiotic Stars. Xi. Orbits For Southern S-Type Systems: Hen 3-461, Sy Mus, Hen 3-828, And Ar Pav, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood
Infrared Spectroscopy Of Symbiotic Stars. Xi. Orbits For Southern S-Type Systems: Hen 3-461, Sy Mus, Hen 3-828, And Ar Pav, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood
Information Systems and Engineering Management Research Publications
Employing new infrared radial velocities, we have computed spectroscopic orbits of the cool giants in four southern S-type symbiotic systems. The orbits for two of the systems, Hen 3-461 and Hen 3-828, have been determined for the first time, while orbits of the other two, SY Mus and AR Pav, have previously been determined. For the latter two systems, we compare our results with those in the literature. The low mass of the secondary of SY Mus suggests that it has gone through a common envelope phase. Hen 3-461 has an orbital period of 2271 days, one of the longest …
Infrared Spectroscopy Of Symbiotic Stars. X. Orbits For Three S-Type Systems: V1044 Centauri, Hen 3-1213, And Ss 73-96, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood
Infrared Spectroscopy Of Symbiotic Stars. X. Orbits For Three S-Type Systems: V1044 Centauri, Hen 3-1213, And Ss 73-96, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood
Information Systems and Engineering Management Research Publications
Employing new infrared radial velocities, we have computed orbits of the cool giants in three southern S-type symbiotic systems. The orbit for V1044 Cen, an M5.5 giant, has a period of 985 days and a modest eccentricity of 0.16. Hen 3-1213 is a K4 giant, yellow symbiotic with an orbital period of 533 days and a similar eccentricity of 0.18. For the M2 giant SS 73-96 the orbital period is 828 days, and this system has a somewhat larger eccentricity of 0.26. Measurement of the H i Paschen δ emission lines, which may at least partially reflect the motion of …
Warm Ice Giant Gj 3470b – Ii. Revised Planetary And Stellar Parameters From Optical To Near-Infrared Transit Photometry, Lauren I. Biddle, Kyle A. Pearson, Ian J. M. Crossfield, Benjamin J. Fulton, Simona Ciceri, Jason Eastman, Travis Barman, Andrew W. Mann, Gregory W. Henry, Andrew W. Howard, Michael H. Williamson, Evan Sinukoff, Diana Dragomir, Laura Vican, Luigi Mancini, John Southworth, Adam Greenberg, Jake D. Turner, Robert Thompson, Brian W. Taylor, Stephen E. Levine, Matthew W. Webber
Warm Ice Giant Gj 3470b – Ii. Revised Planetary And Stellar Parameters From Optical To Near-Infrared Transit Photometry, Lauren I. Biddle, Kyle A. Pearson, Ian J. M. Crossfield, Benjamin J. Fulton, Simona Ciceri, Jason Eastman, Travis Barman, Andrew W. Mann, Gregory W. Henry, Andrew W. Howard, Michael H. Williamson, Evan Sinukoff, Diana Dragomir, Laura Vican, Luigi Mancini, John Southworth, Adam Greenberg, Jake D. Turner, Robert Thompson, Brian W. Taylor, Stephen E. Levine, Matthew W. Webber
Information Systems and Engineering Management Research Publications
It is important to explore the diversity of characteristics of low-mass, low-density planets to understand the nature and evolution of this class of planets. We present a homogeneous analysis of 12 new and 9 previously published broad-band photometric observations of the Uranus-sized extrasolar planet GJ 3470b, which belongs to the growing sample of sub-Jovian bodies orbiting M dwarfs. The consistency of our analysis explains some of the discrepancies between previously published results and provides updated constraints on the planetary parameters. Our data are also consistent with previous transit observations of this system. The physical properties of the transiting system can …
Infrared Spectroscopy Of Symbiotic Stars. Viii. Orbits For Three S-Type Systems: Ae Arae, Y Coronae Australis, And Ss 73-147, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood
Infrared Spectroscopy Of Symbiotic Stars. Viii. Orbits For Three S-Type Systems: Ae Arae, Y Coronae Australis, And Ss 73-147, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood
Information Systems and Engineering Management Research Publications
With new infrared radial velocities we have computed orbits of the M giants in three southern S-type symbiotic systems. AE Ara and SS 73-147 have circular orbits with periods of 803 and 820 days, respectively. The eccentric orbit of Y CrA has a period that is about twice as long, 1619 days. Except for CH Cyg it is currently the S-type symbiotic system with the longest period for which a spectroscopic orbit has been determined. The Paschen δ emission line velocities of AE Ara are nearly in antiphase with the M giant absorption feature velocities and result in a mass …
Infrared Spectroscopy Of Symbiotic Stars. Vii. Binary Orbit And Long Secondary Period Variability Of Ch Cygni, Kenneth H. Hinkle, Francis C. Fekel, Richard R. Joyce
Infrared Spectroscopy Of Symbiotic Stars. Vii. Binary Orbit And Long Secondary Period Variability Of Ch Cygni, Kenneth H. Hinkle, Francis C. Fekel, Richard R. Joyce
Information Systems and Engineering Management Research Publications
High-dispersion spectroscopic observations are used to refine orbital elements for the symbiotic binary CH Cyg. The current radial velocities, added to a previously published 13 year time series of infrared velocities for the M giant in the CH Cyg symbiotic system, more than double the length of the time series to 29 years. The two previously identified velocity periods are confirmed. The long period, revised to 15.6 ± 0.1 yr, is shown to result from a binary orbit with a 0.7 M☉ white dwarf and 2 M☉ M giant. Mass transfer to the white dwarf is responsible for the symbiotic …
Multiwavelength Constraints On The Day–Night Circulation Patterns Of Hd 189733b, Heather Knutson, David Charbonneau, Nicolas B. Cowan, Jonathan J. Fortney, Adam P. Showman, Eric Agol, Gregory W. Henry, Mark E. Everett, Lori E. Allen
Multiwavelength Constraints On The Day–Night Circulation Patterns Of Hd 189733b, Heather Knutson, David Charbonneau, Nicolas B. Cowan, Jonathan J. Fortney, Adam P. Showman, Eric Agol, Gregory W. Henry, Mark E. Everett, Lori E. Allen
Information Systems and Engineering Management Research Publications
We present new Spitzer observations of the phase variation of the hot Jupiter HD 189733b in the MIPS 24 μm bandpass, spanning the same part of the planet's orbit as our previous observations in the IRAC 8 μm bandpass (Knutson et al. 2007). We find that the minimum hemisphere-averaged flux from the planet in this bandpass is 76% ± 3% of the maximum flux; this corresponds to minimum and maximum hemisphere-averaged brightness temperatures of 984 ± 48 K and 1220 ± 47 K, respectively. The planet reaches its maximum flux at an orbital phase of 0.396 ± 0.022, corresponding to …
Infrared Spectroscopy Of Symbiotic Stars. Vi. Combined Orbits For Two S-Type Systems: V455 Scorpii And Ss 73-90, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood, Ian D. Howarth
Infrared Spectroscopy Of Symbiotic Stars. Vi. Combined Orbits For Two S-Type Systems: V455 Scorpii And Ss 73-90, Francis C. Fekel, Kenneth H. Hinkle, Richard R. Joyce, Peter R. Wood, Ian D. Howarth
Information Systems and Engineering Management Research Publications
We have combined new infrared radial velocities and previously obtained spectropolarimetric observations to compute orbits of the M6 giants in two southern S-type symbiotic systems. The spectropolarimetric data enable the orbital inclinations of the systems to be determined, placing greater constraints on the properties of the components. V455 Sco has a circular orbit with a period of 1398 ± 6 days and an inclination of 94° ± 1°. The orbit of SS 73-90 has a period of 898 ± 5 days, a modest eccentricity of 0.16, and an inclination of 97° ± 7°. The center of mass velocity of each …
Infrared Spectroscopy Of Symbiotic Stars. Ii. Orbits For Five S-Type Systems With Two-Year Periods, Francis C. Fekel, Kenneth H. Hinkle, Richard Joyce, Michael F. Skrutskie
Infrared Spectroscopy Of Symbiotic Stars. Ii. Orbits For Five S-Type Systems With Two-Year Periods, Francis C. Fekel, Kenneth H. Hinkle, Richard Joyce, Michael F. Skrutskie
Information Systems and Engineering Management Research Publications
Infrared radial velocities have been used to determine orbital elements for the cool giants of five well-known symbiotic systems, Z And, AG Dra, V443 Her, AX Per, and FG Ser, all of which have orbital periods near the two-year mean period for S-type symbiotics. The new orbits are in general agreement with previous orbits derived from optical velocities. From the combined optical and infrared velocities, improved orbital elements for the five systems have been determined. Each of the orbital periods has been determined solely from the radial-velocity data. The orbits are circular and have quite small mass functions of 0.001–0.03 …
Optical Variability In The Unusual K5 V Infrared-Excess Star Hd 98800, Gregory W. Henry, Douglas S. Hall
Optical Variability In The Unusual K5 V Infrared-Excess Star Hd 98800, Gregory W. Henry, Douglas S. Hall
Information Systems and Engineering Management Research Publications
The dusty infrared-excess star HD 98800 (K5 V) was observed for several weeks in the spring of 1993 by the Vanderbilt/Tennessee State 0.4 m automatic photoelectric telescope. It was found to be a variable star with an amplitude of 0.07 mag in V and a period of 14.7 days. We show, by comparison with other chromospherically active variable stars and constant stars with good observational histories, that the Rossby number for HD 98800, determined to be 0.30, places it well within the regime of stars whose convective envelopes and rotation rates combine to drive a magnetic dynamo strong enough to …
Observations Of The Ca Ii Infrared Triplet In Chromospherically Active Single And Binary Stars, Robert C. Dempsey, Bernard W. Bopp, Gregory W. Henry, Douglas S. Hall
Observations Of The Ca Ii Infrared Triplet In Chromospherically Active Single And Binary Stars, Robert C. Dempsey, Bernard W. Bopp, Gregory W. Henry, Douglas S. Hall
Information Systems and Engineering Management Research Publications
Spectroscopic observations of the Ca II infrared triplet (8498, 8542, 8662 A) have been obtained for 45 stars which are known or suspected to be chromospherically active. The sample includes both single and binary stars of spectral types from F2 to M5 spanning luminosity classes III, IV, and V. Several different types of activity diagnostics were measured, and their relative merits are discussed. Dependence of chromospheric emission upon rotation period, luminosity, temperature, and duplicity are analyzed. Synchronous binaries show a slight trend of increased emission with decreasing period while the asynchronous binaries show abnormally high activity levels for their rotation …