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Full-Text Articles in Physical Sciences and Mathematics
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 …
Two K Giants With Supermeteoritic Lithium Abundances: Hde 233517 And Hd 9746, Suchitra C. Balachandran, Francis C. Fekel, Gregory W. Henry, Han Uitenbroek
Two K Giants With Supermeteoritic Lithium Abundances: Hde 233517 And Hd 9746, Suchitra C. Balachandran, Francis C. Fekel, Gregory W. Henry, Han Uitenbroek
Information Systems and Engineering Management Research Publications
Two unusual Li-rich K giants, HDE 233517 and HD 9746, have been studied. Optical spectroscopy and photometry have been obtained to determine the fundamental parameters of HDE 233517, a single K2 III with an extremely large infrared excess. The spectra yield Teff=4475 K, logg=2.25, [Fe/H]=-0.37, vsini=17.6 km s-1, and a non-LTE logɛ(7Li)=4.22. Photometric observations reveal low-amplitude light variability with a period of 47.9 days. Combined with other parameters, this results in a minimum radius of 16.7 Rsolar and minimum distance of 617 pc. Comparison of spectra obtained in 1994 and 1996 show profile variations in Hα and the Na D …
Photometric Variability In A Sample Of 187 G And K Giants, Gregory W. Henry, Francis C. Fekel, Stephen M. Henry, Douglas S. Hall
Photometric Variability In A Sample Of 187 G And K Giants, Gregory W. Henry, Francis C. Fekel, Stephen M. Henry, Douglas S. Hall
Information Systems and Engineering Management Research Publications
We have used three automatic photoelectric telescopes to obtain photometric observations of 187 G, K, and (a few) M0 field giants. We find low-amplitude photometric variability on timescales of days to weeks on both sides of the coronal dividing line (CDL) in a total of 81 or 43% of the 187 giants. About one-third of the variables have amplitudes greater than 0.01 mag in V. In our sample the percentage of variable giants is a minimum for late-G spectral classes and increases for earlier and later classes; all K5 and M0 giants are variable. We also obtained high-resolution, red wavelength …
Infrared Spectroscopy Of Symbiotic Stars. I. Orbits For Well-Known S-Type Systems, Francis C. Fekel, Richard Joyce, Kenneth H. Hinkle, Michael F. Skrutskie
Infrared Spectroscopy Of Symbiotic Stars. I. Orbits For Well-Known S-Type Systems, Francis C. Fekel, Richard Joyce, Kenneth H. Hinkle, Michael F. Skrutskie
Information Systems and Engineering Management Research Publications
First results are reported for a program of monitoring symbiotic-star velocities in the 1.6 μm region with infrared-array technology. Infrared radial velocities have been used to determine single-lined spectroscopic orbits for six well-known symbiotic stars, EG And, T CrB, CI Cyg, BX Mon, RS Oph, and AG Peg. 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 six systems have been determined. Each of the orbital periods has been determined solely from the radial-velocity data. With the addition of our new velocities, the …
Photometric And Ca Ii H And K Spectroscopic Variations In Nearby Sun-Like Stars With Planets. Iii., Gregory W. Henry, Sallie L. Baliunas, Robert A. Donahue, Francis C. Fekel, Willie Soon
Photometric And Ca Ii H And K Spectroscopic Variations In Nearby Sun-Like Stars With Planets. Iii., Gregory W. Henry, Sallie L. Baliunas, Robert A. Donahue, Francis C. Fekel, Willie Soon
Information Systems and Engineering Management Research Publications
We present the results of an analysis of time-series photometry, Ca II H and K spectrophotometry, and high-dispersion visible spectra of nine nearby Sun-like stars recently identified as having planets. For the six stars whose presumed planets have orbital periods of less than 4 months (τ Boo, 51 Peg, υ And, ρ1 Cnc, ρ CrB, and 70 Vir), sine-curve fits to the photometric data show no variations with semiamplitude greater than 1 or 2 parts in 104. Photometric variations in 47 UMa are similarly small, although our photometric data of this star are slightly affected by variability …