Photometric and spectroscopic study of R CMa

Radhakrishnan, Krishnan; Sarma, M. B. K.; Abhyankar, K. D.

doi:10.1007/bf00650246

Cited by 13 publications

(10 citation statements)

References 9 publications

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“…We conclude that this binary system is in a circular orbit. It is also interesting to note that the abrupt period change Radhakrishnan, Sarma, & Abhyankar (1984). Filled hexagons show the moments of primary minima observed in the present study.…”

Section: Period Variationssupporting

confidence: 72%

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Near-Infrared Photometric Studies of R Canis Majoris

Varricatt

Ashok

1999

The Astronomical Journal

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We present here the Ðrst light curves of the peculiar Algol binary system R Canis Majoris obtained in the near-infrared photometric bands J and K. The light curves are Ðtted for a semidetached model with the Wilson-Devinney light-curve synthesis program. The parameters of the system are derived. Published light curves in the optical photometric bands (U, B, V , and of Guinan, V light U n , B n , V n , Hb w , Hb n curve of Sato, and and light curves of Edalati, Khalesse, & Riazi) are reanalyzed and the Ha w Ha n results are compared. The temperature of the secondary component derived from the light-curve T 2 analysis shows an increase toward the near-IR wavelengths, achieving maximum in the K band. The secondary minima are deeper by 0.03 and 0.07 mag and the primary minima are shallower by 0.02 and 0.03 mag in the J and K bands, respectively, than what is expected in these bands from the secondary temperature and primary radius derived from the V band. In the case of the Ha and Hb light curves, the narrowband light curves yielded higher than the broadband light curves. The values of derived T 2 T 2 from these bands are found to be higher than those derived from the light curves observed in the neighboring wavelengths. We consider the possibility of the di †erence in the strength of photospheric absorption of Ha and Hb lines in the primary and the secondary as a reason for the high values of derived T 2 from these light curves.Five epochs of primary minima and four epochs of secondary minima are obtained in the present study. The increased depth of the secondary minima in the near-IR bands compared with the optical bands enabled us to determine the moments of secondary minima with nearly the same accuracy as those of primary minima. All the secondary minima appear at phase 0.5, and the durations are equal for the primary and the secondary eclipses. The epochs of primary minima follow the nearly sinusoidal O[C curve that has been observed for this star in previous studies. The values of O[C for the secondary minima were in the same range as those of the primary minima observed by us. We conclude that the system is in a circular orbit. Our observed epochs of primary minima support the presence of a third component in the system, as proposed by Radhakrishnan, Sarma, & Abhyankar. The e †ect of the presence of a third, noneclipsing, light source would be to suppress the observed depths of both the eclipses, whereas in this system we Ðnd that the secondary eclipse depth is being enhanced and the primary eclipse depth is being suppressed compared with expectations. So we have not Ðtted for a third light in our light-curve analysis, leaving the nature of the third body, if present, undetermined from our present light-curve analysis.The J-band light curve of R CMa Ðtted well with a bolometric albedo of the secondary star A 2 \ 0.5, as expected for a star with a convective atmosphere. But the K-band light curve showed a value of is also found to be higher in the broadband light curves than in the narrowband light A ...

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Section: Period Variationssupporting

confidence: 72%

“…Radhakrishan, Sarma, & Abhyankar (1984) interpreted this as due to a light-time e †ect arising from the presence of a third body in the system, a dM star or a white dwarf of about 0.5 Radhakrishan, Sarma, & Abhyankar (1985) conducted M _ . a photometric study of R CMa in the UBV bands using the Russell-Merrill method (Russell & Merrill 1952).…”

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confidence: 99%

Near-Infrared Photometric Studies of R Canis Majoris

Varricatt

Ashok

1999

The Astronomical Journal

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“…The ideas underlying photometric mass ratios go back many decades to early attempts to model eclipsing binary light curves. The genesis of the idea that the lobe-filling condition can be used to estimate a photometric mass ratio appears in Wood [8] where he argues that it provides a limit on the mass ratio for R Canis Majoris, a system now known [9,10] to be semidetached. Wilson [11] gives a brief discussion of the early work that led to the use of photometric mass ratios, and explains why they can be very accurate in certain situations, namely semidetached and overcontact binaries that exhibit complete (i.e., total/annular) eclipses.…”

Section: Photometric Mass Ratiosmentioning

confidence: 99%

Mass Ratio and Spot Parameter Estimation from Eclipsing Binary Star Light Curves

Terrell

2022

Galaxies

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Eclipsing binary stars have a rich history of contributing to the field of stellar astrophysics. Most of the available information on the fundamental properties of stars has come from the analysis of observations of binaries. The availability of powerful computers and sophisticated codes that apply physical models has resulted in determinations of masses and radii of sufficient accuracy to provide critical tests of theories of stellar structure and evolution. Despite their sophistication, these codes still require the guiding hand of trained scientists to extract reliable information. The computer code will produce results, but it is still imperative for the analyst to ensure that those results make astrophysical sense, and to ascertain their reliability. Care must be taken to ensure that we are asking the codes for parameters for which there is information in the data. The analysis of synthetic observations with simulated observational errors of typical size can provide valuable insight to the analysis process because the parameters used to generate the observations are known. Such observations are herein analyzed to guide the process of determining mass ratios and spot parameters from eclipsing binary light curves. The goal of this paper is to illustrate some of the subtleties that need to be recognized and treated properly when analyzing binary star data.

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“…Let us also note in this context, however, the third body in the R CMa-system (cf. Radhakrishnan et al, 1983). Total angular momentum, in the evolution of some Algol systems, might not be so much lost as redistributed, if there happened to be some third orbit in which it could be deposited.…”

Section: Possible Interpretations and Checksmentioning

confidence: 99%

The q-Log P Distribution of Classical Algols

Budding

1984

International Astronomical Union Colloquium

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Data on a large sample (∼400) of candidates for the classical Algol-type eclipsing binary configurations have been collected. The mass-ratio q has been calculated on the assumption of their semi-detached nature, and then compared with corresponding period for some subsets of the sample. The tendency to slight overluminosity (compared with corresponding MS stars) of the primaries in classical Algols is confirmed.The role of the loss of angular momentum in classical Algol evolution is considered, together with a method for determining representative parameters to characterize such effects using the sample data. The possible existence of a class of post-contact classical Algols is noted.

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Photometric and spectroscopic study of R CMa

Cited by 13 publications

References 9 publications

Near-Infrared Photometric Studies of R Canis Majoris

Near-Infrared Photometric Studies of R Canis Majoris

Mass Ratio and Spot Parameter Estimation from Eclipsing Binary Star Light Curves

The q-Log P Distribution of Classical Algols

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