Broad-band Light Curves Research Articles

Discontinuities in the dynamic spectrum of the pulsar 0823+26

The 1400 MHz dynamic spectrum of the pulsar 0823+26 exhibits sharp discontinuities which are characterized by changes in the diffractive scintillation pattern over transition times of ∼2 minutes. The discontinuities occur during periods in which the pulsar's broad-band (40 MHz) light curve is undergoing strong oscillations with periods of ∼15 minutes. We believe these effects are due to coherent interference between multiple images created by strong refraction in the interstellar medium. In effect, we observe the discontinuities in the dynamic spectrum when the scintillation patterns of different images (each traveling different optical paths) alternately dominate the received intensity

H-beta photometry of V1010 Ophiuchi

view Abstract Citations (16) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS H-Beta Photometry of V1010 Ophiuchi Corcoran, M. F. ; Siah, M. J. ; Guinan, E. F. Abstract An analysis is presented of previously unpublished intermediate and narrow band H-beta light curves of the short period eclipsing binary V1010 Oph. The temperature of the primary is determined directly by comparing the UV continuum with Kurucz model atmospheres and solve the broadband lightcurve using the Wilson-Devinney program. The present solution has the primary filling its Roche lobe while the secondary is detached from its lobe. An asymmetry in the light curve in which first quadrature (0.25 P) is brighter than the second quadrature (0.75 P) may be the result of local heating of the inner surface of the secondary by mass transfer from the primary. The present semidetached solution indicates that the system is probably evolved. Publication: The Astronomical Journal Pub Date: May 1991 DOI: 10.1086/115810 Bibcode: 1991AJ....101.1828C Keywords: Astronomical Photometry; Eclipsing Binary Stars; H Beta Line; Light Curve; Ophiuchi Clouds; Stellar Evolution; Stellar Systems; Astrophysics; STARS: INDIVIDUAL; STARS: ECLIPSING BINARIES full text sources ADS | data products SIMBAD (1)

A study of the eclipsing cataclysmic variable Lanning 90

Photometric and spectroscopic observations of Lanning 90 (V1776 Cyg) show that it is an eclipsing cataclysmic variable with an orbital period of 3h57m. The shape of the eclipse is variable, and the brightness out of eclipse can change by over a magnitude in less than a day. The broad-band light curves do not show a hump before eclipse, but time-resolved spectroscopy of one orbit suggests that the H-alpha emission-line strength peaks near phase 0.75. Observations of a number of orbits, however, are needed to confirm that the line strength depends on phase. The velocity amplitude of the primary is 144 + or - 20 km/s as measured from the wings of the H-alpha line. The masses of the components, the orbital inclination, and semimajor axis are estimated from the observations, but the derived system parameters are suspect since the spectroscopic phase lags the photometric phase by 70 deg. A similar shift has been observed in DW UMa and is attributed to a disturbance on the disk which contaminates the Balmer line wings. 20 refs.

Visible and near-infrared lightcurves of eight asteroids

B lightcurves are presented for seven asteroids (4, 20, 29, 31, 39, 115, and 349) together with visual and infrared color curves (BV, BK, VJ, and JK). A V broadband lightcurve for 40 Harmonia is also included. Color variations are observed for three asteroids (4, 31, and 115). The variation in the colors of 4 Vesta is discussed in terms of differences in surface composition. Pole positions and shapes are estimated for 20 Massalia, 29 Amphitrite, 31 Euphrosyne, and 39 Laetitia. Various UBVRIJHK colors are listed for these asteroids as well as for 5, 19, 44, 52, 83, 145, 386, and 471.

Migrating Waves in Solar-Type Short-Period Eclipsing Binaries

One of the properties of RS CVn-like binaries is the presence of cyclic fluctuations, sometimes called “migrating waves”, in the V and other broad-band lightcurves. These fluctuations, perhaps due to spots, vary in amplitudes and periods, in the sense that, the longer the orbital period of the RS CVn system, the higher the amplitude of the “wave”, which may be up to 30-35% of the total light variation. Therefore, in short-period (less than one day) RS CVn binaries, these fluctuations are generally difficult to be detected.