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Full-Text Articles in Physical Sciences and Mathematics
A False Planet Around Hd 192263, Gregory W. Henry, Robert A. Donahue, Sallie L. Baliunas
A False Planet Around Hd 192263, Gregory W. Henry, Robert A. Donahue, Sallie L. Baliunas
Information Systems and Engineering Management Research Publications
We present new high-precision Strömgren photometry and Ca II H and K spectrophotometry of HD 192263. Based on radial velocity variations detected previously by two groups, this K2 V star was thought to host a 0.75 MJup (minimum mass) planetary companion in a 24 day orbit. Our photometric observations reveal periodic variations that match the purported planetary orbital period, while the Ca II H and K emission fluxes are modulated on half the planetary period. This suggests that rotational modulation of the visibility of stellar surface activity is the source of the observed radial velocity variations. Therefore, HD 192263 should …
Chromospherically Active Stars. Xxi. The Giant, Single-Lined Binaries Hd 89546 And Hd 113816, Francis C. Fekel, Gregory W. Henry, Joel A. Eaton, Julius Sperauskas, Douglas S. Hall
Chromospherically Active Stars. Xxi. The Giant, Single-Lined Binaries Hd 89546 And Hd 113816, Francis C. Fekel, Gregory W. Henry, Joel A. Eaton, Julius Sperauskas, Douglas S. Hall
Information Systems and Engineering Management Research Publications
We have obtained spectroscopy and photometry of the chromospherically active, single-lined spectroscopic binaries HD 89546 and HD 113816. HD 89546 has a circular orbit with a period of 21.3596 days. Its primary has a spectral type of G9 III and is somewhat metal-poor with [Fe/H]~-0.5. HD 113816 has an orbit with a period of 23.6546 and a low eccentricity of 0.022. Its mass function is extremely small, 0.0007 Msolar, consistent with a very low inclination. The primary is a slightly metal-poor K2 III. A decade or more of photometric monitoring with an automatic telescope demonstrates that both systems display brightness …
Velocity Observations Of Multiple-Mode Asymptotic Giant Branch Variable Stars, Kenneth H. Hinkle, Thomas Lebzelter, Richard R. Joyce, Francis C. Fekel
Velocity Observations Of Multiple-Mode Asymptotic Giant Branch Variable Stars, Kenneth H. Hinkle, Thomas Lebzelter, Richard R. Joyce, Francis C. Fekel
Information Systems and Engineering Management Research Publications
Numerous infrared spectroscopic observations were obtained of nine asymptotic giant branch (AGB) field M giants that have multiple periods of light variability. Each star has a short period of several months, which is typical of low amplitude pulsation for stars on the AGB, as well as a long period of 1–3 yr, which is significantly longer than the predicted fundamental-mode pulsations for these stars. The location of these stars in the AGB period-luminosity relation is discussed. For six of the nine giants we found radial-velocity periods that confirm the long-period light variability. Although we considered the possibility that the velocity …