Publications of Jean Manfroid
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See detailOn period determination methods
Heck, A.; Manfroid, Jean ULiege; Mersch, G.

in Astronomy and Astrophysics. Supplement Series (1985), 59

It is noted that the two large families of period determination techniques based on the Fourier transform and on the nonparametric algorithms derived from the theta-criterion by Lafler and Kinman (1965 ... [more ▼]

It is noted that the two large families of period determination techniques based on the Fourier transform and on the nonparametric algorithms derived from the theta-criterion by Lafler and Kinman (1965) are not equivalent to each other under general conditions. Instead, at best, all criteria may be expressed as the ratio of two quadratic forms. Numerical simulations have been conducted in order to compare the performance of Deeming's (1975) Fourier method, Burki et al.'s (1978) autocorrelation method, Lafler and Kinman's (1965) method, and the Renson (1978) and Stellingwerf (1978) methods. When applied to single-periodic phenomena, the tests indicate that none of the methods is clearly superior. [less ▲]

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See detailComètes particulières et fragmentation des noyaux
Manfroid, Jean ULiege

Article for general public (1985)

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See detailOn photometric standards and color transformation
Manfroid, Jean ULiege

in Calibration of Fundamental Stellar Quantities (1985)

The author has carried out a preliminary investigation of a method of observation and reduction which leads to a large improvement in the accuracy of the color transformation of photometric measurements ... [more ▼]

The author has carried out a preliminary investigation of a method of observation and reduction which leads to a large improvement in the accuracy of the color transformation of photometric measurements. This method involves the use of extra filters for some of the observations. It is argued that the better precision obtained is well worth the additional telescope work. [less ▲]

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See detailThe stability and accuracy of the uvby system.
Manfroid, Jean ULiege

in Calibration of Fundamental Stellar Quantities (1985)

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See detailCatch the Minima - a Real Challenge on V348-SAGITTARII
Heck, A.; Manfroid, Jean ULiege

in International Amateur-Professional Photoelectric Photometric Communications (1985)

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See detailMira's role in RR Tel revisited
Heck, A.; Manfroid, Jean ULiege

in Cool Stars with Excesses of Heavy Elements (1985)

The present uvby data, IUE FES measurements and American Association of Variable Star Observers visual estimates of the very slow nova RR Tel show that the object has gone through periodic variations in ... [more ▼]

The present uvby data, IUE FES measurements and American Association of Variable Star Observers visual estimates of the very slow nova RR Tel show that the object has gone through periodic variations in visual light since it started fading in 1949 after the outburst it incurred in 1944. The period is, however, not constant, and varies between 350 and 410 days, confirming Mayall's (1957) statement and contradicting the conclusions of later investigators. Synchronized variations of a Mira in the infrared and of a blue component indicate that the Mira mass outflow probably varies in a phase with its pulsations. Large variations occur in visual light on a time scale of a few weeks. [less ▲]

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See detailOn the homogenization of photometric data.
Manfroid, Jean ULiege; Heck, A.

in Calibration of Fundamental Stellar Quantities (1985)

Catalogs of averaged photometric data have been published for several photometric systems. The homogenizing procedures used to produce them are not without pitfalls. The authors question the accuracy of ... [more ▼]

Catalogs of averaged photometric data have been published for several photometric systems. The homogenizing procedures used to produce them are not without pitfalls. The authors question the accuracy of these methods with the available data. [less ▲]

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See detailOn the Homogenization of Photometric Data
Heck, Andre; Manfroid, Jean ULiege

in Calibration of Fundamental Stellar Quantities, Eds. D.S. Hayes, L.E. Pasinetti & A.G.D. Philip, D. Reidel Publ. Co., Dordrecht (1985) p. 565-567 (1985)

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See detailInternational Directory of Astronomical Associations and Societies - IDAAS 1986
Heck, Andre; Manfroid, Jean ULiege

in International Directory of Astronomical Associations and Societies - IDAAS 1986, Publ. Spec. CDS 8 (1985), iv + 266pp. (1985)

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See detailA Real Challenge: The minimums of V348 Sgr
Heck, Andre; Manfroid, Jean ULiege

in Bulletin de l'Association Francaise d'Observateurs d'Etoiles Variables (1985), 33

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See detailOccultation detection of a Neptune ring segment
Hubbard, W. B.; Brahic, A.; Bouchet, P. et al

in LPI Contributions (1985), 559

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See detailStability and accuracy of the UVBY system
Manfroid, Jean ULiege

in Astronomy and Astrophysics (1984), 141

In order to evaluate the transformation errors for stars of various types and classes, the author has simulated observations made with standard and non-standard equipments. Large deviations which cannot ... [more ▼]

In order to evaluate the transformation errors for stars of various types and classes, the author has simulated observations made with standard and non-standard equipments. Large deviations which cannot be corrected are observed mainly for objects outside the range 0.0 < b-y < 0.4 and in the u filter. The rectangular passbands have many advantages however. They can be very stable and are accurately reproducible. Hence the problem of nontransformable outputs may not exist between such systems. Since many uvby observations are to be collected with such equipments, it could be advantageous to define a new standard "rectangular" uvby system along with the conventional one. [less ▲]

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See detailOn the He Weak Variable HD 28843
Manfroid, Jean ULiege; Mathys, G.; Cousins, A. W. J.

in Information Bulletin on Variable Stars (1984), 2625

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See detailThe Bright Eclipsing Binary HD 208496
Manfroid, Jean ULiege; Mathys, G.

in Information Bulletin on Variable Stars (1984), 2616

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See detailPossible detection of a 10-kilometer sized object around Neptune.
Roques, F.; Sicardy, B.; Bouchet, P. et al

in Bulletin of the American Astronomical Society (1984, September 01)

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See detail1984 N1
Hafner, R.; Manfroid, Jean ULiege

in International Astronomical Union Circulars [=IAUCs] (1984), 3968

IAUC 3968 available at Central Bureau for Astronomical Telegrams.

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See detailCyclic RR Telescopii
Heck, Andre; Manfroid, Jean ULiege

Article for general public (1984)

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See detailOn the Photometric Variations of HD 28843 and HD 29009
Manfroid, Jean ULiege; Mathys, G.

in Information Bulletin on Variable Stars (1984), 2551

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See detailAppulse of SAO 186001 to Neptune
Manfroid, Jean ULiege; Gutierrez, F.; Hafner, R. et al

in International Astronomical Union Circulars [=IAUCs] (1984), 3962

IAUC 3962 available at Central Bureau for Astronomical Telegrams. IAUC 3962 available at Central Bureau for Astronomical Telegrams.

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See detailAn estimate of V348 SGR effective temperature
Heber, U.; Heck, A.; Houziaux, Léo ULiege et al

in Fourth European IUE Conference (1984, July 01)

The IUE low dispersion spectra of the irregular variable V348 Sgr taken close to maximum light were compared with those of the B-type stars HD 53138 and HD 58350 and with those of the extreme helium stars ... [more ▼]

The IUE low dispersion spectra of the irregular variable V348 Sgr taken close to maximum light were compared with those of the B-type stars HD 53138 and HD 58350 and with those of the extreme helium stars HD 12448 and LS II + 33 deg 005. Energy distribution of V348 Sgr was compared with a theoretical continuous distribution based on UBVRI and uvby photometric measurements close to maximum brightness. Results show that V348 Sgr has a carbon-rich atmosphere and a spectral type between s+B3 and s+B5 in the UV (corresponding to between B3 Ia and B5 Ia in the visible). The object probably belongs to the group of extreme helium stars with an effective temperature of 15,000 to 16,000 K. [less ▲]

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