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The Dust Envelope of the Symbiotic Nova HM Sge
We have studied the brightness and color variations of the symbioticnova HM Sge based on longterm UBVRJHKLM photometry of the star and dataon its energy distribution in the middle infrared (7.7 22.7 µm)obtained with the low-resolution spectrometers of the IRAS satellite andISO orbital observatory. We have also calculated models for thesteady-state, spherically symmetrical, extended dust envelope of thestar for two extreme heating cases: heating only by radiation from thecool component of the system and by the combined radiation from bothcomponents. Model fitting to the IRAS and ISO data indicates that modelswith a single, central Mira-type source are more appropriate. Thisindicates that the radiation of the hot component is largely processedby the surrounding gas, and does not substantially affect the infraredspectrum of the symbiotic nova directly. The mean spectral energydistribution based on 1983 IRAS data differs appreciably from the ISOspectrum obtained on October 1, 1996. The observed evolution of theenvelope spectrum probably reflects an increase of the density anddecrease of the temperature of the dust grains near the inner boundaryof the envelope, related to a decrease of the luminosity and increase ofthe temperature of the hot component. We estimate the total mass-lossrate, velocity of gas expansion at the outer envelope boundary, andupper limit for the mass of the central source of radiation.
| The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
| 1978-1993 UBVR-JHKLMN photometry of the very slow nova and symbiotic Mira HM Sagittae. I. The data
Our long term photoelectric and photographic monitoring of the very slownova and symbiotic Mira HM Sge in the UBVR_J_ and JHKLMN bands over theperiod 1978-1993 is presented. The 350 photographic magnitudes and the393 photoelectric measurements here given constitute a highlyhomogeneous set of data well suited for detailed investigation of theoutburst evolution, the Mira pulsation activity and the physicalproperties of the circumstellar material. The data analysis is left toan accompanying paper.
| Analysis of Neckel and Chini standard stars in the UBVRI photometric system
This paper studies the list of 60 faint standard stars of Neckel andChini (1980) in the UBVRI Johnson photometric system. We have re-reducedthe standard stars using our own method of reduction from a large numberof selected observations made at the Observatorio Astronomico Nacionaland at the Centro Astronomico Hispano-Aleman, both at Calar Alto, Spain,and at the Observatorio del Roque de los Muchachos, La Palma Island,Spain. The reduction method used is explained and the results are givenfor the four colors used: (B-V), (U-B), (V-R), and (V-I), together withthe V magnitude, that is, we have corrected many standard stars for eachcolor and magnitude. These results are supported with graphs whereresidual color is plotted against corresponding color (or magnitude).Finally, our (V-R) and (V-I) results are compared to those of Taylor etal. (1989), with a good correspondence.
| The properties of the Neckel-Chini VRI system
Cousins (1980) data for 54 of the standard stars of Neckel and Chini(1980) and published measurements are used to investigate the propertiesof the Neckel-Chini VRI system. For red stars, this system diverges fromthe Johnson (1962) system, despite frequent claims of identity betweenthe two. The Neckel-Chini and Cousins systems, however, are closelycomparable. Both of these conclusions were previously reached in a paperby Bessell (1983); fair to good quantitative agreement with his resultsare obtained. Reddening ratios, the scatter in the Neckel-Chinistandard-star data, and the effect of this scatter on publishedmeasurements for program stars, are discussed. Transformations from theNeckel-Chini system to the Cousins system are given.
| Sixty faint UBVRI standards
A list of 60 faint UBVRI standards is presented. Their UBV magnitudesare in the system introduced by Johnson (1955) and their V-R and V-Icolors are in the system of the Arizona Tonantzintla catalogue byIriarte et al. (1965). These stars are spread over an equatorial belt atan angle less than 30 deg, so that they can be observed as well fromnorthern as from southern sites.
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Группы:
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Наблюдательные данные и астрометрия
| Созвездие: | Стрела |
| Прямое восхождение: | 19h48m54.69s |
| Склонение: | +18°12'51.3" |
| Видимая звёздная величина: | 9.369 |
| Собственное движение RA: | 1.6 |
| Собственное движение Dec: | -7.7 |
| B-T magnitude: | 9.54 |
| V-T magnitude: | 9.384 |
Каталоги и обозначения:
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