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HD 200739


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Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS
Radial velocities have been determined for a sample of 2930 B2-F5 stars,95% observed by the Hipparcos satellite in the north hemisphere and 80%without reliable radial velocity up to now. Observations were obtainedat the Observatoire de Haute Provence with a dispersion of 80Ä,mm(-1) with the aim of studying stellar and galactic dynamics.Radial velocities have been measured by correlation with templates ofthe same spectral class. The mean obtained precision is 3.0 km s(-1)with three observations. A new MK spectral classification is estimatedfor all stars. Based on observations made at the Haute ProvenceObservatory, France and on data from The Hipparcos Catalogue, ESA.Tables 4, 5 and 6 are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr or viahttp://cdsweb.u-strasbg.fr/Abstract.htm

Multiperiodicity in the atypical delta SCT star AN Lyn
New uvby data collected of AN Lyn together with the reanalysis of olddata establish that this star is a multiperiodic pulsator. Threeindependent frequencies (nu _1=10.1756, nu _2=18.1309 and nu _3=9.5598cd(-1) ) and some interactions between them are found to be present inthe light curve. Changes in amplitude with a large time scale areconfirmed for the main frequency. Moreover, changes in amplitude arealso present for the secondary frequencies, especially for nu _3. Aftersubtraction of the secondary frequencies from the light curves, theclassical O-C method has been used to analyse the behaviour of the mainperiod. A comparison is made between AN Lyn and the other two knowndelta Sct stars with atypical light curves, i.e., V1719 Cyg and V798Cyg. New uvby data have been also collected for V1719 Cyg and the O-Cmethod has been used to analyse the behaviour of the main period. It isfound that the main pulsation of this star can be well described bymeans of a linear ephemeris with a period of P=0.(d) 26729700 over thelast eighteen years. Finally, analysis of the different data setsavailable in the literature do not reveal significative changes in theamplitude of the main frequency of V1719 Cyg. Table 5 will be accessibleonly in electronic form at the CDS

Other Maximum for the Pulsating Star V1719 Cyg (HD 200925)
Not Available

Lists of photometric AM candidates
The Geneva photometric m parameter (Nicolet and Cramer, 1982) is used inorder to select Am photometric candidates from the Rufener (1981)catalogue. Two lists are given, the first containing field stars and thesecond cluster stars. According to the photometric criteria thediffusion process probably responsible for the Am phenomenon takes placerather quickly as Am candidates are present in young clusters. It isconfirmed that the phenomenon is enhanced by low rotational velocity andhigh metallicity. The age seems to slightly affect the Am phenomenon.

Properties of AM stars in the Geneva photometric system
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&A....92..289H&db_key=AST

Observational stability in AM stars
Differential photoelectric photometry is carried out in metallic-linestars suspected of variability and in the pulsating Am: star HR 8210.The pulsational stability of classical Am stars is confirmed and thehypothesis that the Am phenomenon is the result of diffuse elementseparation is still consistent with the observations. The variability ofHR 8210 is confirmed too. The behavior of this star should beinterpreted as evidence of a multiple-period structure.

HD 200925, a New Short Period Variable Star
Not Available

UBVRI photometry of 225 AM stars
UBVRI photometry of 225 Am stars taken from Mendoza's (1974) catalog ispresented. The results are compared with those obtained by Feinstein(1974) for 21 of the stars and with the values of Johnson et al. (1966).It is assumed that in the first approximation the (V-I) color index ofan unreddened Am star is equal to that of a normal main-sequence star; astandard main sequence is defined for A and early F stars, and thefive-color photometry is analyzed by means of plots of U-V vs. V-I, B-Vvs. V-I, and V-R vs. V-I. Mean color deficiencies of Am stars areexamined, and it is suggested that an unreddened star located below themain-sequence A0-F2 line in the (V-I, U-V) plane is a photometric Amstar. It is concluded that: (1) photometric Am stars have colordeficiencies (as a function of V-I) which, on the average, are 0.07 magin (U-V) color index and 0.025 mag in (B-V) color index; (2) Am starswith V-R less than 0.25 mag may also have a color deficiency of about0.01 mag; (3) Am stars with V-R greater than 0.3 mag may have a colorexcess of approximately 0.01 mag; and (4) Am stars with V-R between 0.25and 0.3 mag may have normal colors.

Multicolor photometry of metallic-line stars. III. A photometric catalogue
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974RMxAA...1..175M&db_key=AST

Catalogue of AM stars with known spectral types
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973A&AS...10..385H&db_key=AST

Catalogue et bibliographie des étoiles A à spectre particulier - Deuxième supplément
Not Available

Catalogue et bibliographie des étoiles A à spectre particulier Premier supplément
Not Available

Peculiar and Metallic-Line a - Stars in a Galactic Zone.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1959ApJ...129...88S&db_key=AST

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观测天体数据

星座:天鵝座
右阿森松:21h03m19.61s
赤纬:+50°48'07.1"
视星:8.292
距离:220.264 天文距离
右阿森松适当运动:14.9
赤纬适当运动:16.7
B-T magnitude:8.525
V-T magnitude:8.312

目录:
适当名称   (Edit)
HD 1989HD 200739
TYCHO-2 2000TYC 3600-75-1
USNO-A2.0USNO-A2 1350-13353091
HIPHIP 103918

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