The hitherto neglected close binary V486 Car is studied with the aid of newly applied satellite photometry (HIPPARCOS and TESS), high-dispersion spectrometry (High Efficiency and Resolution Canterbury University Large Echelle Spectrograph) and ground-based B and V photometry. While the sinusoidal light variations are suggestive of a near-contact system, the stars have only shallow eclipse, so highly confident parametrization becomes challenging. We find: M-1 = 2.1 +/- 0.1, M-2 = 0.4 +/- 0.1; R-1 = 3.20 +/- 0.02, R-2 = 1.48 +/- 0.01; (circle dot); T-e1 = 10000 +/- 500, T-e2 = 6200 +/- 200 (K); distance = 162 +/- 12 (pc). New times of minima for V486 Car have been examined, including recent observations from TESS. The role of the relatively significant O'Connell effect is examined. As well as the conspicuous asymmetry from the main effect of about 0.036 mag (V), a jitter, with amplitude of about 0.005 V mag and quasi-period of order similar to 10 d is noticed. There is a tendency for such photometric excursions at one maximum to precede those at the other. As well, the O-C data indicate the presence of a low-mass star similar to 0.3 M-circle dot in an orbit separated by a few au from the close binary. More accurate and plentiful spectroscopic data would be requisite for further investigations. A brief discussion reviews possible approaches to understanding the system in the context of near-contact binary scenarios.

The southern early-type, young, eccentric-orbit eclipsing binary NO Puppis forms the A component of the multiple star Gaia DR3 5528147999779517568. The B component is an astrometric binary now at a separation of about 8.1 arcsec. There may be other fainter stars in this interesting but complex stellar system. We have combined several lines of evidence, including TESS data from four sectors, new ground-based BVR photometry, HARPS (ESO) and HERCULES (UCMJO) high-resolution spectra and astrometry of NO Pup. We derive a revised set of absolute parameters with increased precision. Alternative optimal curve-fitting programs were used in the analysis, allowing a wider view of modelling and parameter uncertainties. The main parameters are as follows: M-Aa = 3.58 +/- 0.11, M-Ab = 1.68 +/- 0.09 (M-circle dot); R-Aa=2.17 +/- 0.03, R-AB=1.51 +/- 0.06 (R-circle dot), and T-eAa= 13 300 +/- 500, T-eAb =7400 +/- 500 (K). We estimate approximate masses of the wide companions, Ba and Bb, as M-Ba = 2.0 and M-Bb 1.8 (M-circle dot). The close binary's orbital separation is a = 8.51 +/- 0.05 (R-circle dot); its age is approximately 20 Myr and distance 172 +/- 1 pc. The close binary's secondary (Ab) appears to be the source of low amplitude delta Scuti-type oscillations, although the form of these oscillations is irregular and unrepetitive. Analysis of the lambda 6678 He I profile of the primary show synchronism of the mean bodily and orbital rotations. The retention of significant orbital eccentricity, in view of the closeness of the A-system components, is unexpected and poses challenges for the explanation that we discuss.

Model orbits have been fitted to 27 physical double stars listed in a 1922 catalog. A Markov Chain Monte Carlo technique was applied to estimate best-fitting values and associated uncertainties for the orbital parameters. Dynamical masses were calculated using parallaxes from the Hipparcos mission and are presented in this paper with the estimates of the orbital parameters for the 27 systems. The resulting mass estimates of the current study are in good agreement with a recently published study, as are comparisons with the orbital parameters listed by the Washington Double Star catalog, confirming the validity of the optimization methodology.

It has been said that the Venus transit of 24 May 1032 was observed by Ibn Sina and recorded among his written output. This was critically evaluated by Goldstein (1969), who demurred on the claim. However, Kapoor's (2013) thorough review has shown that Ibn Sina could well have observed this event, giving rise to an ongoing interest in the geocentric versus heliocentric discussion, such as was picked up by Nasr ad-Din Tusi and others. This eventually culminated in the general acceptance of the Copernican world-system. We reconsider the special circumstances of the reported discovery and show that Ibn Sina indeed could have observed the event, with a discussion of its significance along the way to a Sun-centered world.

ABSTRACT New photometry, including TESS data, have been combined with recent spectroscopic observations of the Orion Ib pulsating triple-star system VV Ori. This yields a revised set of absolute parameters with increased precision. Two different programmes were utilized for the light-curve analysis, with results in predictably close agreement. The agreement promotes confidence in the analysis procedures. The spectra were analysed using the FDBinary programme. The main parameters are as follows: M1 = 11.56 ± 0.14 and M2 = 4.81 ± 0.06 (M⊙). We estimate an approximate mass of the wide companion as M3 = 2.0 ± 0.3 M⊙. Similarly, R1 = 5.11 ± 0.03, R2 = 2.51 ± 0.02, R3 = 1.8 ± 0.1 (R⊙); Te1 = 26600 ± 300, Te2 = 16250 ± 420, and Te3 = 10000 ± 1000 (K). The close binary’s orbital separation is a = 13.91 (R⊙); its age is 8 ± 2 (Myr) and its photometric distance is 396 ± 7 pc. The primary’s β Cep type oscillations support these properties and confirm our understanding of its evolutionary status. Examination of the well-defined λ6678 He i profiles reveals the primary to have a significantly low projected rotation: some 80 per cent of the synchronous value. This can be explained on the basis of the precession of an unaligned spin axis. This proposal can resolve also observed variations of the apparent inclination and address other longer term irregularities of the system reported in the literature. This topic invites further observations and follow-up theoretical study of the dynamics of this intriguing young multiple star.

It has been said that the Venus transit of 24 May 1032 was observed by Ibn Sina and recorded among his written output. This was critically evaluated by Goldstein (1969), who demurred on the claim. However, Kapoor's (2013) thorough review has shown that Ibn Sina could well have observed this event, giving rise to an ongoing interest in the geocentric versus heliocentric discussion, such as was picked up by Nasr ad -Din Tusi and others. This eventually culminated in the general acceptance of the Copernican world -system. We reconsider the special circumstances of the reported discovery and show that Ibn Sina indeed could have observed the event, with a discussion of its significance along the way to a Sun -centered world.

Contact binaries challenge contemporary stellar astrophysics with respect to their incidence, structure, and evolution. We explore these issues through a detailed study of two bright examples: S Ant and epsilon CrA, that permit high-resolution spectroscopy at a relatively good S/N ratio. The availability of high-quality photometry, including data from the TESS satellite as well as Gaia parallaxes, allows us to apply the Russell paradigm to produce reliable up-to-date information on the physical properties of these binaries. As a result, models of their interactive evolution, such as the thermal relaxation oscillator scenario, can be examined. Mass transfer between the components is clearly evidenced, but the variability of the O'Connell effect over relatively short-time scales points to irregularities in the mass transfer or accretion processes. Our findings indicate that S Ant may evolve into an R CMa type Algol, while the low mass ratio of epsilon CrA suggests a likely merger of its components in the not-too-distant future

Auckland Observatory has a proud history of variable star research that extends back more than half a century. In this paper we briefly outline events leading up to the founding of the Observatory and discuss its construction, before summarizing highlights from the Observatory's stellar photometry program with the Zeiss 50-cm Edith Winstone Blackwell Telescope.

Estimates of orbital parameters were made using a Bayesian optimization technique on astrometric data for 25 visual binary systems catalogued a century ago by the ninth Astronomer Royal, Sir Frank Dyson. An advantage of this method is that it provides reliable, unbiased uncertainty estimates for the optimized parameters. Reasonable agreement is found for the short period (< 100 yr) systems between the current study and Dyson, with superior estimation for the longer systems through the inclusion of an additional century of data. Dynamical masses are presented for the systems through the inclusion of parallax measurements.

Theoretical values of the structural coefficient k(2), have been calculated in dependance on mass and age. The results are relatively more accurately tested from observations of apsidal motion in young and massive binariy systems. For this context, values of k(2) were also derived for eleven well-studied and observed eccentric eclipsing-binaries: CW Cep, V 478 Cyg, AG Per, V 453 Cyg, V 578 Mon, PV Cas, V 451 Oph, V 380 Cyg, IQ Per, HD 152,218 and NO Pup. Our new k(2) values are calculated by integrating the Clairaut-Radau equation numerically using the 'EZ-Web' version of the Eggleton stellar modeling program. Models are in the range between 2.6 and 17.5 M-circle dot, constructed with the two metallicities Z = 0.015 and Z = 0.02. From the observations, we obtained a linear regression formula relating system-mean k(2) values for given logarithmic mass and age. This correlation can be used to test the match between apsidal motion results and the separately derived ages of the components of a binary system. From these findings, we conclude that empirically determined k(2) values have better determined from young and massive binaries than binaries in general. Apsidal motion constants, when calculated from reliable data, can be used to test the ages of the stars. These checks can be made with our correlation for the system NO Pup, which is the subject of current studies.

ABSTRACT New spectrometric (HERCULES) and ground-based multicolour photometric data on the multiple star V410 Puppis are combined with satellite photometry (HIPPARCOS and TESS), as well as historic astrometric observations. Absolute parameters for V410 Pup Aab are derived: MAa = 3.15 ± 0.10, MAb = 1.83 ± 0.08 (M⊙); RAa = 2.12 ± 0.10, RAb = 1.52 ± 0.08 (R⊙); a = 6.57 ± 0.04 R⊙; TAa = 12500 ± 1000, TAb = 9070 ± 800(K), and photometric distance 350 ± 10 (pc). We report the discovery of a low-amplitude SPB variation in the light curve and also indications of an accretion structure around V410 Pup B as well as emission cores in V410 Pup C. We argue that V410 Pup is probably a young formation connected with the Vela 2 OB Association. The combined evidence allows an age in the range 7–25 Myr from comparisons with standard stellar evolution modelling.

ABSTRACT New spectrometric data on V Pup are combined with satellite photometry [HIPPARCOS and recent Transiting Exoplanet Survey Satellite (TESS)] to allow a revision of the absolute parameters with increased precision. We find: M1 = 14.0 ± 0.5, M2 = 7.3 ± 0.3 (M⊙); R1 = 5.48 ± 0.18, R2 = 4.59 ± 0.15 (R⊙); T1 26 000 ± 1000, T2 24 000 ± 1000 (K), age 5 ± 1 (Myr), photometric distance 320 ± 10 (pc). The TESS photometry reveals low-amplitude (∼0.002 mag) variations of the β Cep kind, consistent with the deduced evolutionary condition and age of the optical primary. This fact provides independent support to our understanding of the system as in a process of Case A type interactive evolution that can be compared with μ1 Sco. The ∼10 M⊙ amount of matter shed by the overluminous present secondary must have been mostly ejected from the system rather than transferred, thus taking angular momentum out of the orbit and keeping the pair in relative close proximity. New times of minima for V Pup have been studied and the results compared with previous analyses. The implied variation of period is consistent with the Case A evolutionary model, though we offer only a tentative sketch of the original arrangement of this massive system. We are not able to confirm the previously reported cyclical variations having a 5.47-yr period with the new data, though a direct comparison between the HIPPARCOS and TESS photometry points to the presence of third light from a star that is cooler than those of the close binary, as mentioned in previous literature.

A new ephemeris, period change analysis and light curve modeling of the W UMa-type eclipsing binary BF Pav are presented in this study. Light curves of the system taken in BVRI filters from two observatories, in Australia and Argentina, were modeled using the Wilson-Devinney code. The results of this analysis demonstrate that BF Pav is a contact binary system with a photometric mass ratio q = 1.460 +/- 0.014, a fillout factor f = 12.5%, an inclination of 87.97 +/- 0.45 deg and a cold spot on the secondary component. By applying the distance modulus formula, the distance of BF Pav was calculated to be d = 268 +/- 18 pc which is in good agreement with the Gaia EDR3 distance. We obtain an orbital period increase at a rate of 0.142 s century(-1) due to a quadratic trend in the O - C diagram. Also, an alternative sudden period jump probably occurred which could be interpreted as a rapid mass transfer from the lower mass star to its companion of about Delta M = 2.45 x 10(-6) M (circle dot). Furthermore, there is an oscillatory behavior with a period of 18.3 +/- 0.3 yr. Since BF Pav does not seem to have significant magnetic activity, this behavior could be interpreted as the light-time effect caused by an undetected third body in this system. In this case, the probability for the third body to be a low mass star with M >= 0.075 M (circle dot) or a brown dwarf is 5.4% and 94.6% respectively. If we assume i ' = 90 degrees, a (3) = 8.04 +/- 0.33 AU. The mass of the secondary component was also determined following two different methods which result close to each other.

We present combined photometric and spectroscopic analyses of the southern binary star PU Pup. High-resolution spectra of this system were taken at the University of Canterbury Mt. John Observatory in the years 2008 and again in 2014-15. We find the light contribution of the secondary component to be only $\sim$2\% of the total light of the system in optical wavelengths, resulting in a single-lined spectroscopic binary. Recent TESS data revealed grazing eclipses within the light minima, though the tidal distortion, examined also from HIPPARCOS data, remains the predominating light curve effect. Our model shows PU Pup to have the more massive primary relatively close to filling its Roche lobe. PU Pup is thus approaching the rare `fast phase' of interactive (Case B) evolution. Our adopted absolute parameters are as follows: $M_1$ = 4.10 ($\pm$0.20) M$_{\odot}$, $M_2$ = 0.65 ($\pm$0.05) M$_{\odot}$, $R_{1}$ = 6.60 ($\pm$0.30) R$_{\odot}$, $R_2$ = 0.90 ($\pm$0.10) R$_{\odot}$; $T_{1}$ = 11500 ($\pm$500) K, $T_{2}$ = 5000 ($\pm$350) K; photometric distance = 186 ($\pm$20) pc, age = 170 ($\pm$20) My. The less-massive secondary component is found to be significantly oversized and overluminous compared to standard Main Sequence models. We discuss this discrepancy referring to heating from the reflection effect.

An update is given on the exoplanet research collaboration between Nielsen (a marketing research company), Brigham Young University, and NZ universities with the National University of Singapore, which has been expanded to include a community college in the US. Key achievements from the past year are outlined, including density estimates for HD 209458 and Kepler 1 from radial velocity and transit fits. A comparison between the WinFitter optimizer and other techniques is outlined, showing that WinFitter estimated statistical errors are essentially in line (bar a scaling proportion) with those estimated via Markov Chain Monte Carlo techniques.

We present an updated O-C diagram of the light-time variations of the eclipsing binary (component B) in the system QZ Carinae as it moves in the long-period orbit around the non-eclipsing pair (component A). This includes new Variable Stars South members' measures from 2017 to 2019, BRITE satellite observations in 2017 and 2018, and 100 previously unpublished measures made at Auckland Observatory from 1974 to 1978. We conclude that QZ Carinae has not yet completed one orbit of the two pairs since discovery in 1971. The duration of totality of primary eclipses was measured to be 0.295 +/- 0.02 day (7.08 +/-0.48 hours), rather longer than earlier values from light curve models. Other observational findings include the shape of primary and secondary eclipses and small-scale short-term brightness changes.

\textit{Kepler} teleskobu ile gozlenen HAT-P-7 b (Kepler-2 b), Kepler-6 b ve Kepler-8 b gezegenleri gecis isik egrilerinin cozumleri, yeni bir analiz yazilimi olan \textsc{WinFitter} ile yapildi ve ilgili sistemlerin yorunge elemanlari ile yildizlarin ve gezegenlerin fiziksel parametreleri belirlendi.

We have carried out an intensive study of photometric (Kepler Mission) and spectroscopic data on the system Kepler-2 (HAT-P-7A) using the dedicated software WinFitter 6.4. The mean individual data-point error of the normalized flux values for this system is 0.00015, leading to the model’s specification for the mean reference flux to an accuracy of ∼0.5 ppm. This testifies to the remarkably high accuracy of the binned data-set, derived from over 1.8 million individual observations. Spectroscopic data are reported with the similarly high-accuracy radial velocity amplitude measure of ∼2 m s−1. The analysis includes discussion of the fitting quality and model adequacy. Our derived absolute parameters for Kepler-2 are as follows: $M_{p}$ (Jupiter) 1.80 ± 0.13; $R_{\star }$ 1.46 $\pm 0.08 \times 10^{6}$ km; $R_{p}$ 1.15 $\pm 0.07 \times 10^{5}$ km. These values imply somewhat larger and less condensed bodies than previously catalogued, but within reasonable error estimates of such literature parameters. We find also tidal, reflection and Doppler effect parameters, showing that the optimal model specification differs slightly from a ‘cleaned’ model that reduces the standard deviation of the ∼3600 binned light curve points to less than 0.9 ppm. We consider these slight differences, making comparisons with the hot-Jupiter systems Kepler-1 (TrES-2) and 13. We confirm that the star’s rotation axis must be shifted towards the line of sight, though how closely depends on what rotation velocity is adopted for the star. From joint analysis of the spectroscopic and photometric data we find an equatorial rotation speed of 11 ± 3 km s−1. A slightly brighter region of the photosphere that distorts the transit shape can be interpreted as an indication of the gravity effect at the rotation pole; however we note that the geometry for this does not match the spectroscopic result. We discuss this difference, rejecting the possibility that a real shift in the position of the rotation axis in the few years between the spectroscopic and photometric data-collection times. Alternative explanations are considered, but we conclude that renewed detailed observations are required to help settle these questions.

A brief review is given of a university outreach programme by a commercial organisation, which uses the Kepler exoplanet data. Key insights derived from this research are presented, along with discussion of the benefi ts and challenges of such a collaboration between industry and academia. It is hoped that this account will be an inspiring example for others to emulate.

We present combined photometric and spectroscopic analyses of the southern multiple star HX Vel. High-resolution spectra of this system were taken at the University of Canterbury Mt. John Observatory in the years 2009-2015. Absolute parameters for HX Vel tend to confirm its young and near-main-sequence nature. We specify the main adopted parameters of the (non-eclipsing) close binary as follows: M-1 = 8.5 +/- 1.7, M-2 = 5.4 +/- 1.2, R-1 = 5.0 +/- 0.3, R-2 = 3.1 +/- 0.2, (circle dot); T-1 25 000 +/- 1300, T-2 20 000 +/- 2500 (K); systemic M-V -4.2 +/- 0.2. These parameters are sensitive to the low inclination, where we find a small disparity between the photometrically optimal 28 +/- 2 degrees and an adopted value of 26 degrees that gives better consistency with main-sequence stellar modelling. The relationship of HX Vel to the galactic cluster IC 2395 and OB association Vela OB1C is also considered, in the context of photometric parallaxes found for HX Vel and other cluster members.