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Louth, H.

Publications and source records attributed to Louth, H..

7 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

The photometric period of 39 AY Ceti

A photometric period of 77.65 days is derived for 39 AY Ceti through a comparison of photoelectric photometry obtained in 1971 and 1972 with that obtained in the periods 1980-1981 and 1981-1982. JD 2444636.0 is an epoch of minimum light, and the full amplitude is found to have been as large as 0.18 mag in V. It is noted that the mean light level has dropped by almost 0.2 mag over the last decade. The present binary star is also noteworthy in light of the recently discovered white dwarf secondary component, and because radial velocity measurements indicate an eccentricity as large as 0.1 and an orbital period which, at 57.1 days, differs considerably from the photometric period presented.

Hopkins, J. L.↗
NASA NTRS1983

Three years of photometry of IM Pegasi = HR 8703

Differential photometry of this K1 IV-III p RS CVn-type binary in 1978-79, 1979-80, and 1980-81 at eight different observatories shows that the variability, discovered originally by Herbst, is periodic. The mean of three different determinations of the photometric period was 24(d).39 + or 0(d).03, about 1 percent shorter than the orbital period of 24(d).649 determined spectroscopically by Harper. The total range observed during these three years was for V from 5(m).60 to 5(m).85. The light curve was nearly sinusoidal but always noticieably asymmetric, with the sense reversing sometime between 1979-80 and 1980-81.

Eaton, J. A.↗
NASA NTRS1982

Four years of photometry of DK Draconis = HR 4665

Differential BV photometry of the K0 III + K0 III long-period RS CVn-type binary DK Dra = HR 4665 in 1977, 1978, 1979, and 1980 at eight different observatories is presented. A least squares fit to times of maximum and minimum light yields the ephemeris JD = 2,443,219.5 + 63.75 d E for times of minimum. This photometric period is 1% shorter than the spectroscopically determined orbital period 64.44 d. The light curve was symmetrical and roughly sinusoidal in 1979 and 1980 but was asymmetrical in 1977 and 1978, with a faster rise to maximum. During these four years DK Dra varied between V = 6.07 and 6.35 m.

Eaton, J. A.↗
NASA NTRS1982

HR 7275 - A new variable star

Three years of photometry in V and B of the UBV system are presented to confirm the suspicion of Herbst (1973) that HR 7275 is a variable star. The photometry is used to derive the photometric period, which proves to be about 3% shorter than the spectroscopically determined optical period of 28.59 d. Total variation observed during the three years was 0.22 m in the V, and the light curve was always asymmetrical.

Fried, R. E.↗
NASA NTRS1981

54 Cam - A new variable star

Differential photometry of the RS CVn-type binary 54 Cam is presented, which shows that the light was variable with a period of 10.163 + or - 0.009 d, and with an amplitude increase from 0.03 to 0.06 m between 1979 and 1980. The photometric period of 10.163 d is 9% shorter than the orbital period of 11.0764 d, and is suggested as an explanation for the radio emission from 54 Cam due to a process of connection, disruption, and reconnection of magnetic field lines.

Hall, D. S.↗