bluuebunny/crossref_metadata_2025 huggingface dataset:
The matching of assets to liabilities
Authors: Wise A. J.
Published: April 2012

1.1. The concept of the matching of assets to liabilities is fundamental in matters of finance. In its broadest sense matching is relevant both to the investment of life office and pension funds and to actuarial calculations in relation to those funds.

1.2. Matching is inherently connected with the uncertainty of future conditions, as measured by such indicators as rates of interest, inflation and currency exchange. It is when conditions do not work out as hoped for or expected that the risks associated with mis-matching can materialize. Whether considering investment policy or an actuarial calculation it is important that the nature of a portfolio which minimizes these risks be appreciated, and yet it is often difficult to specify such a portfolio with precision. This may not be a source of difficulty in practice when the judgement of the actuary is applied to the problem in hand, but there is evident scope for refinement of the concepts.
The effect of taxation on the pricing of government securities
Authors: Leung A. P.
Published: April 2012

0.1. Since the concept of immunization was introduced in Redington (1952) many new ideas have been advanced in connexion with the pricing of government securities. It is shown in Bierwag (1977) for example, that the applicability of an immunization strategy depends on the form of movements assumed possible in the yield curve.

0.2. Much of this earlier work has been framed in deterministic terms, where prices or yields are assumed to be known in advance, and uncertainty has been introduced via arbitrary instantaneous changes in those yields. It is easily shown that portfolios of securities with a given mean term or duration are immune (in the sense of yielding the same return at the required realization date) to certain forms of instantaneous change.
The effect of duplicate policies upon the variance of sickness data
Authors: Daw R. H.
Published: April 2012

The data presented in C.M.I.R. (1979) and (1984) on the Sickness Experience for Individual PHI Policies contain duplicate policies. In dealing with these data it is therefore necessary to be able to take account of the effect of duplicates on the variance of sickness claim inceptions and of weeks of sickness claims.
Address by the President. The necessity for change
Authors: Moore Peter Gerald
Published: April 2012

A hundred years ago last Saturday, on 24 November 1884. Dr Thomas Sprague. my sometime predecessor in this office, delivered an Address. He opened by announcing that, after prolonged and painful negotiations, a Royal Charter had been granted to the Institute placing it, in his words “…as a professional body publicly recognized as representing, and entitled to speak in the name of, actuaries in the United Kingdom”. It was impossible, he wisely added, to predict exactly what new duties would devolve upon the profession as a consequence of this change.
The recent trend of mortality in Great Britain
Authors: Daykin C. D.
Published: April 2012

This note continues an annual series on mortality rates in Great Britain; the previous note in the series appeared in J.I.A. 111, 181 and dealt with mortality in 1981.

Following the 1981 Census, revised estimates of the ‘home’ population of England and Wales since 1961 have been published. These allow for revision of past estimates in the light of the Census and also for a new definition of ‘home’ population, which brings the concept closer to that of ‘resident’ population. The ‘home’ population is now defined as including residents temporarily outside the country but excluding foreign visitors. It includes members of both H.M. and foreign forces stationed in the United Kingdom but excludes members of H.M. forces who are stationed abroad.
Edmond Halley: astronomer and actuary
Authors: Heywood Geoffrey
Published: April 2012

Edmond Halley, who was born in 1656 and died in 1742, is well known generally because of the Comet which bears his name. He is not, however, associated to any great extent with other activities and if it were not for the Comet it is likely that most people today would never even have heard of him. Outside the actuarial profession, and perhaps to some extent even within it, it is not generally known that in 1693 he constructed a life table from the bills of mortality in the German city of Breslau and then went on to calculate from that table annuity rates on one, two and three lives. Reference to this was formerly included in the introduction to the Year Book, but this has now been shortened and the reference to Halley has disappeared.
Pensions: The problems of today and tomorrow. A summary of the Report published by the Institute of Actuaries and of the discussion at Staple Inn on 11 June 1985
Authors: Haberman S.
Published: April 2012

From the very outset of the formation of pensions schemes in the United Kingdom, actuaries have been involved in their design, investment, valuation and solvency. A review of issues of the Journal of the Institute of Actuaries in England and the Transactions of the Faculty of Actuaries in Scotland over the last 40 years would show how schemes have become more complicated and more comprehensive, how the economic and equity problems have increased and how the actuarial profession has successfully adapted its theory and practice to accommodate change. After World War II the rapid growth in occupational pension schemes together with the post-Beveridge expansion in State social security led to concerns about the overall effect on the national economy. As a consequence, in 1954 a report on “The growth of pension rights and their impact on the national economy” was presented to both the Institute and the Faculty of Actuaries by Bernard Benjamin, Francis Bacon and Donald Elphinstone.
Determination of the rate of investment return for the discounting of general insurance outstanding claims
Authors: Taylor G. C.
Published: April 2012

The paper concerns the situation in which an evaluation of outstanding claims is discounted, in anticipation of investment return earned by the funds supporting that liability. Factors bearing upon the choice of an appropriate rate of return to be assumed in this evaluation are considered.

The ‘standard approach’ to this problem is criticized in two main respects:

(i) there is usually no statement (indeed, no consideration) of whether the discounted value of outstanding claims is to be associated with assets at book, market, or some other value;

(ii) the discounting of outstanding claims is often performed by means of an assumed ‘inflation gap’, i.e. an assumed difference between future rates of inflation and investment return.

Various other matters germane to the determination of an appropriate rate of investment return are listed in Section 2.

Sections 3 and 5 deal particularly with points (i) and (ii) raised above. It is suggested that, in certain circumstances, an evaluation of outstanding claims which fails to address (i) or is carried out on an ‘inflation gap’ basis will be virtually meaningless.

Section 4 deals with the case of an insurance fund in which assets are matched with technical liabilities by amount and term. The considerations which would cause the rate of investment return projected in these circumstances, to differ from that projected in the case of an absence of matching are discussed.

Section 6 deals with the issue of exactly which assets are to be regarded as supporting the liability for outstanding claims. It is apparent that the identification of such assets will affect the rate of return to be regarded as referable to outstanding claims. Particular matters considered include:

(i) assets to be associated with acquisition of new business (and hence not with outstanding claims);

(ii) debtor and creditor items. particularly outstanding premiums and inwards loans.

Section 7 gives a numerical example of the projection of future rates of investment return. This is done by means of a computer projection of various items of a hypothetical insurance fund, taking into account projected future:

(i) interest rates;

(ii) rate of growth of new premium;

(iii) the required distribution of assets by sector;

(iv) profitability of business underwritten.

Conclusions on the various matters considered are dotted through the paper. For convenience, they are collected together in Section 8.
A statistical study of the variability of sickness data
Authors: Daw R. H.
Published: April 2012

1.1. In 1979 the first set of graduated sickness rates derived from the data supplied by a number of insurance companies was published by the PHI Sub-Committee (C.M.I.R. 4, 1979).

Sickness is a much more complex phenomenon than mortality. I get the impression from working on the 1972–75 sickness experience of, as it were, a certain looseness and lack of coherence in the data which I have not found in mortality data. Some of this could be due to the much smaller size of the data and to the heterogeneity of the experience. Much of the latter has been removed in the Standard experience of 1975–78 but, not having studied these data, I can say nothing about the effect of this. It is therefore not surprising that the PHI Sub-Committee had considerable doubts “about the possibility of judging the success of the graduation by applying standard statistical tests” such as those normally used for mortality data.
Using options to price maturity guarantees
Authors: Beenstock Michael , Brasse Valerie
Published: April 2012

The discussion on Maturity Guarantees, as applied to unit linked life assurance policies, has followed two quite distinct paths—the conventional or mainstream approach, as exemplified by Benjamin (1976) and endorsed by the Maturity Guarantees Working Party (MGWP 1980) on the one hand, and those who seek to reduce the risks associated with maturity guarantees by using an immunization strategy on the other (Brennan & Schwartz, 1976).
The economic basis of interest rates
Authors: Wilkie A. D.
Published: April 2012

In a discussion I had with Professor J. J. McCutcheon and Dr W. F. Scott, the authors of the new book on compound interest, An Introduction to the Mathematics of Finance (Heinemann 1986) it was suggested that a chapter describing the theoretical economic background to the determination of interest rates might be of interest to actuarial students. I therefore drafted the substance of this note as such a chapter. In the event it was felt that the subject fitted uneasily with the mainly technical and numerical approach to compound interest appropriate for students at that particular stage of the examinations, and that the more theoretical approach in this note would in any case be of wider actuarial interest. It is therefore presented as this note in the Journal. I am grateful to Professor McCutcheon and Dr Scott for agreeing to this, and to the discussions I had with them while the note was being drafted.
On the relationship between gross and net yields to redemption—practical versus theoretical approximations
Authors: Hathaway Neville , Rickard John , Woods Ivan
Published: April 2012

In the market for fixed-interest securities, several variants of the yield to redemption (YTR) concept are used. The YTR of a stock is simply the internal rate of return which the holder can expect to receive if he she holds the stock until maturity. Since income tax has to be paid by some, if not all investors on the interest received, and in some cases on the capital gain as well, a distinction is made between the gross YTR and the net YTR.
The financial management of a with-profit long term fund — some questions of disclosure
Authors: Lyon C. S. S.
Published: April 2012

1.1 There are three starting points for this paper. The first is Marshall Field's challenging Presidential Address to the Institute of Actuaries in 1986 on the subject of ‘Risk and Expectation’. The second is the example, still fresh in our minds, of a medium-sized mutual life office which overstretched itself and found it necessary to merge with a competitor. The third is the impending requirement, stemming from the Financial Services Act 1986, to give an investment client, including the holder or prospective holder of an insurance savings contract, what is described as ‘best advice’.
The relationship between gross and net yields to redemption
Authors: Worger H. O.
Published: April 2012

1. With reference to the Actuarial Note by Messrs Hathaway, Rickard & Woods (HR&W) J.I.A.113, 509–520 there is a simpler way, which is much easier to calculate, of approximating from the gross yield to redemption to the net yield, with taxation on the basis assumed by HR&W.
Movements of pension contributions and fund levels when rates of return are random
Authors: Dufresne Daniel
Published: April 2012

This paper proposes a simple model for studying the variability of contribution rates and fund levels, when rates of return are random. The funding methods considered are those which (1) produce an actuarial liability (AL) and a normal cost (NC), and which (2) adjust the latter by a constant fraction ‘k’ of the difference between AL and the actual fund (this discrepancy is known as the ‘unfunded liability’; for a description of actuarial cost methods the reader is referred to Trowbridge (1952), Winklevoss (1977) or Turner et al. (1984)). Thus at every valuation date

total contribution = normal cost + k × (unfunded liability).
Proposals for the statutory basis of valuation of the liabilities of linked long-term insurance business
Authors: Fine A. E. M. , Headdon C. P. , Hewitson T. W. , Johnson C. M. , Lumsden I. C. , Maple M. H. , O'Keeffe P. J. L. , Pook P. J. , Purchase D. E. , Robinson D. G.
Published: April 2012

1.1 The background to the production of this paper is somewhat involved, but is necessary for an understanding of why it contains what it does. Readers who are familiar with recent developments in the valuation field may proceed straight to Section 2.

1.2 Statutory valuations of long-term insurance business under the Insurance Companies Act 1982 (‘the Act’, which superseded the 1974 and 1981 Acts) and the Insurance Companies Regulations 1981 (‘the current Regulations’) have now been prepared by actuaries for some years. Similarly the guidance issued by the profession to Appointed Actuaries, specifically GN1 and GN8, has also remained substantially unchanged over that period. The time was opportune for valuation practice to be reviewed in the light of recent experience.
The epidemiology of HIV infection and AIDS
Authors: Daykin C. D.
Published: April 2012

The current state of knowledge on the epidemiology of HIV infection and AIDS is reviewed, with extensive references to the medical literature. The particular focus is on those aspects of the epidemiology of HIV infection which are of interest in the formulation of models for projecting the future spread of the virus and its impact in terms of numbers of cases of AIDS and deaths from AIDS.
Some results on the Gompertz and Heligman and Pollard laws of mortality
Authors: Thatcher A. R.
Published: April 2012

The ‘law of mortality’ proposed by Heligman and Pollard is compared with the law of Gompertz and with English Life Table No. 14. Some new mathematical results are derived, including specific equations for the curve of deaths. Some numerical illustrations are given.
The recent trend of mortality in Great Britain
Authors: Daykin C. D.
Published: April 2012

This note continues a regular series on mortality rates in Great Britain, showing the mortality experienced in each age-group in 1988 and comparing this for broad age-groups, on a standardised basis, with mortality in earlier years.
Managing uncertainty in a general insurance company
Authors: Daykin C. D. , Hey G. B.
Published: April 2012

A cash flow model is proposed as a way of analysing uncertainty in the future development of a general insurance company. The company is modelled alongside the market in aggregate so that the impact of changes in premium rates relative to the market can be assessed. An extensive computer model is developed along these lines, intended for use in practical applications by actuaries advising the management of genera1 insurance companies. Simulation methods are used to explore the consequences of uncertainty, particularly in regard to inflation and investments. Some comments are made on the role of actuaries in general insurance. Alternative approaches to describing the behaviour of an insurance firm in the market are considered.
A unitised fund approach to with-profit business
Authors: Squires R. J. , O'Neill J. E.
Published: April 2012

The paper traces the history of the development of a with-profit system for a specialist unit-linked office. The marketing problem, to which this was the chosen solution, is discussed and a number of possible future developments are then considered. The second half of the paper is devoted to discussion of the question of matching assets and liabilities for the range of products developed. Although the paper deals with developments in a particular office the authors' intention is to provide a different perspective on the problems associated with conventional with-profit business which will be of more general interest.
Notes on the Financial Times-Actuaries Equity Share Indices in 1989
Authors: Brumwell J. C. H.
Published: April 2012

The process of updating company classifications continued.

Seventy Index constituents were replaced during 1989, mostly as a result of takeovers, not quite a record. Only 46 replaced them, reflecting the difficulty in finding suitable new non-industrial constituents. The Mining Finance group was discontinued, but Engineering–Aerospace and Water were introduced. Shipping & Transport was renamed Transport.
Underwriting—a dying art?
Authors: Leigh T. S.
Published: April 2012

The paper reviews the underwriting of life assurance and sickness benefits today. It considers both medical and non-medical aspects and how the extra risks should be costed. The paper also deals with financial underwriting. reassurance and the management of death claims. Although the paper presents a ‘state of the art’ picture, it also considers advances via on-line acceptance, expert systems and computer-based training.
A note on life table and multiple-decrement table functions
Authors: Scott W. F.
Published: April 2012

This note considers the mortality table functions, and shows that the usual formulae hold under less restrictive assumptions than those usually made. The foundations of the theory of multiple-decrement tables are also considered, in the context of probability theory.
Life office returns to the Department of Trade and Industry
Authors: Ford A.
Published: April 2012

This paper arose from a report prepared by a working party set up under the auspices of the Research Committee. The views in the paper are my own but they are, to a considerable extent, based upon work done by Messrs J. K. W. Davies and P. N. S. Clark. I am also indebted to Mr R. T. Foster of the Government Actuary's Department for clarifying points arising from the current Regulations.

2. The paper is concerned with the Returns made by Life Offices to the Department of Trade and Industry in accordance with The Insurance Companies (Accounts and Forms) Regulations 1968. The aims of this paper are:

(i) to discuss the objectives of the Returns,

(ii) to discuss whether the questions asked by the present Regulations and the answers currently being given in the Returns achieve these objectives,

(iii) to discuss possible changes in the Regulations, and

(iv) to discuss the role of the actuary in relation to the Returns and also in relation to the auditor.
Simple formulae for valuing stock conversion options
Authors: Carroll P. M.
Published: April 2012

It is quite common for stocks (usually loan stocks) to be issued by companies and purchased by investors, which include among their terms an option to convert at some future date into other stocks (usually ordinary shares) on specific terms. Such options obviously have value, but I am unaware of any simple published method for estimating the value of such options in practical cases. The purpose of this note is to suggest a formula, based upon easily understood estimates of the future market prices of the stocks in question, which may be applied readily in practice to estimate the value of such options.
An approach to the use of computers in actuarial work
Authors: Bennett M. C. , Berry P. K. , Brown G. A. , Farrington G. W. , Hey G. B.
Published: April 2012

Electronic computers have been available commercially for about 20 years. Actuarial interest was soon shown, but although a number of papers have appeared over the years there has been little recent discussion of how computers can best serve the profession.

Many actuaries have little computing experience. To them it may appear a daunting task to learn to use a computer, because many instruction manuals seem, at first sight, extensive and complex. Our principal aim is to demonstrate to them that given suitable permanent facilities it is quite easy to use a computer for actuarial calculations, however complex these may be. We suggest that the complexity of most existing actuarial programming systems is unnecessary, and may have impeded the understanding of the computer's potential by actuaries.
A further report on an investigation into the mortality of diabetics
Authors: Shaw B. H.
Published: April 2012

The results of the investigation from 1945 to 1959 were presented in a paper to the Institute by R. E. Hayward and B. C. Lucena (J.I.A. 91, 286) and readers are referred to this for further detail on practical aspects of the investigation. This further report owes its existence to all those originally involved as well as those specifically involved in the follow-up. Professor J. M. Malins and Dr M. G. FitzGerald have continued to give us the help needed to obtain the required data from the hospital records. Those of our Society particularly involved in producing this follow-up report include B. C. Lucena, R. Betteridge, A. Roberts and M. Willett.
Estimation of radiation interception by winter wheat from measurements of leaf area
Authors: Thorne G. N. , Pearman I. , Day W. , Todd A. D.
Published: April 2012

The percentage (P) of incident photosynthetically active radiation (PAR) reaching the ground was measured in winter wheat crops throughout the season, and related to projected area index (L) of leaves, plus sheaths and stems when present. Between unfolding of the first leaf and appearance of the flag leaf the mean value for the exponential extinction coefficient (K) was 0·46±0·007. The value did not vary with the growth stage of the wheat and was scarcely affected by experimental treatments, apart from effects resulting from the presence of senescent tissues that intercepted light but whose area was not included in L. After anthesis, in crops having between 340 and 540 ears/m2, between 68 and 89% of incident PAR penetrated to below the ears. Relation between the further penetration to the base of the crop canopy and the area of green plus senescent leaf and stem tissue gave K = 0·50. The relation did not change significantly between anthesis and complete senescence.

The relation between P and L was similar whether P was obtained from instantaneous measurements made near midday, 24 h integrals of PAR or percentage ground cover measured photographically.
‘Get back to where you once belonged!’ The positive creative impact of a refresher course for ‘baby-boomer’ rock musicians
Authors: O'Shea Helen
Published: April 2012

This article reports on a study of participants in a Weekend Warriors Program for ‘lapsed’ rock musicians in Melbourne, Australia. It observes musicians over a six-week period that included a jam session, coaching sessions and a gig (concert). It examines the learning pathways of participants and their goals and experiences alongside those of the programme organisers within the comparative context of music learning practices among young and older musicians and in the light of academic research into the midlife ageing process. A question that arises from the data is the extent to which the experience and actions of middle-aged women musicians coincides with the literature on gender in youth rock music scenes and the literature on music, ageing and gender. The article concludes that the Weekend Warriors Program draws on the learning practices that the musicians involved had adopted in their youth and which act as a catalyst for their further musical and social participation and self-directed group learning. Age appeared to create no barrier to their enjoyment or their achievements; indeed in many ways it seemed to make them less inhibited and self-conscious in realising individual objectives that were further encouraged by working within a supportive if loosely bonded group.
Memoryscapes and mediascapes: musical formations of ‘pensioners’ in late 20th-century Sweden
Authors: Hyltén-Cavallius Sverker
Published: April 2012

The late 20th century in Sweden saw the growth of music solely aimed at an elderly audience. This article discusses music within pensioner organisations, first assessing a cassette compilation marketed through the members' magazine of Sweden's largest pensioner organisation and, second, embarking on ethnographies of meetings within a study circle in music-listening arranged through a pensioner organisation, conducted in 1999–2000. The music selection in the cassette compilation diminishes certain genres of the included period and foregrounds others, adding up to a specific homogeneous national memoryscape. A central theme in the study circle was the production and negotiation of generational and individual memoryscapes. The two mediascapes produced different memoryscapes, one being nationally and temporally bounded, the other being at the same time local, transnational and transtemporal. To conclude, the article claims that if we wish to understand the nexus of ageing and music in contemporary society, we need to listen not only to musicians, entrepreneurs and care institutions, but also to their intended audiences.
A note on analytic integrability of planar vector fields
Authors: ALGABA A. , GARCÍA C. , REYES M.
Published: April 2012

We give a new characterisation of integrability of a planar vector field at the origin. This allows us to prove that the analytic systemswhereh,K, Ψ and ξ are analytic functions defined in the neighbourhood ofOwithK(O) ≠ 0 or Ψ(O) ≠ 0 andn≥ 1, have a local analytic first integral at the origin. We show new families of analytically integrable systems that are held in the above class. In particular, this class includes all the nilpotent and generalised nilpotent integrable centres that we know.
k-Sums in Abelian Groups
Authors: GIRARD BENJAMIN , GRIFFITHS SIMON , HAMIDOUNE YAHYA OULD
Published: April 2012

Given a finite subset A of an abelian group G, we study the set k ∧ A of all sums of k distinct elements of A. In this paper, we prove that |k ∧ A| ≥ |A| for all k ∈ {2,. . .,|A| − 2}, unless k ∈ {2, |A| − 2} and A is a coset of an elementary 2-subgroup of G. Furthermore, we characterize those finite sets A ⊆ G for which |k ∧ A| = |A| for some k ∈ {2,. . .,|A| − 2}. This result answers a question of Diderrich. Our proof relies on an elementary property of proper edge-colourings of the complete graph.
ACCEPTANCE, FAIRNESS, AND POLITICAL OBLIGATION
Authors: Song Edward
Published: April 2012

Among the most popular strategies for justifying political obligations are those that appeal to the principle of fairness. These theories face the challenge, canonically articulated by Robert Nozick, of explaining how it is that persons are obligated to schemes when they receive goods that they do not ask for but cannot reject. John Simmons offers one defense of the principle of fairness, arguing that people could be bound by obligations of fairness if they voluntarily accept goods produced by a cooperative scheme. Simmons, however, thinks that such a theory will do little work in justifying political obligations, since virtually no one voluntarily accepts state goods. This paper attempts to advance just such a theory by arguing that states are in fact genuine cooperative schemes and that Simmons is overly pessimistic in his appraisal of whether the majority of citizens accept the goods provided by their states.
The Impact of Gaia and LSST on Binaries and Exoplanets
Authors: Eyer L. , Dubath P. , Mowlavi N. , North P. , Triaud A. , Barblan F. , Siopis C. , Guy L. , Tingley B. , Zucker S. , Evans D.W. , Wyrzykowski L. , Süveges M. , Ivezic Z.
Published: April 2012

Two upcoming large scale surveys, the ESA Gaia and LSST projects, will bring a new era in astronomy. The number of binary systems that will be observed and detected by these projects is enormous, estimations range from millions for Gaia to several tens of millions for LSST. We review some tools that should be developed and also what can be gained from these missions on the subject of binaries and exoplanets from the astrometry, photometry, radial velocity and their alert systems.
Eccentricity of Selected Eclipsing Systems
Authors: Ogłoza W. , Kreiner J. M. , Stachowski G. , Zakrzewski B. , Mikulášek Z. , Zejda M.
Published: April 2012

This paper presents the results of verification of known stars showing evidence of orbital eccentricity and apsidal motion.
Spectroscopic Study of the Early-Type Binary HX Vel A
Authors: Özkardeş Burcu , Sürgit Derya , Erdem Ahmet , Budding Edwin , Soydugan Faruk , Demircan Osman
Published: April 2012

This paper presents high resolution spectroscopy of the HX Vel (IDS 08390-4744 AB) multiple system. New spectroscopic observations of the system were made at Mt. John University Observatory in 2007 and 2008. Radial velocities of both components of HX Vel A were measured using gaussian fitting. The spectroscopic mass ratio of the close binary was determined as 0.599±0.052, according to a Keplerian orbital solution. The resulting orbital elements are a1sini=0.0098±0.0003 AU, a2sini=0.0164±0.0003 AU, M1sin3i=1.19±0.07 M⊙ and M2sin3i=0.71±0.04 M⊙.
Northern Binaries in the Evrena Project
Authors: Bakış V. , Hensberge H. , Zejda M. , de Cat P. , Yılmaz F. , Bloemen S. , Svoboda P. , Demircan O.
Published: April 2012

In the framework of the EVRENA project, high-resolution spectra of northern eclipsing close binaries in stellar groups are obtained with the HERMES Echelle spectrograph at the Mercator telescope (Roque de los Muchachos Observatory). This contribution gives the first results on DV Camelopardalis.
KIC 4544587: An Eccentric, Short Period Binary with δ Scuti Pulsations and Tidally Excited Modes
Authors: Hambleton Kelly , Kurtz Don , Prša Andrej , Bloemen Steven , Southworth John
Published: April 2012

KIC 4544587 is an eclipsing binary star with clear signs of apsidal motion and indications of tidal resonance. The primary component is an early A-type δ Scuti variable, with a temperature of 8270±250 K, whilst the secondary component is an early G-type main sequence star with a temperature of 6500±310 K. The orbital period of this system is 2.18911(1) d, with the light curve demonstrating a hump after secondary minimum due to distortion and reflection. The frequency spectrum of the residual data (the original data with the binary characteristics removed) contains both pressure (p) and gravity (g) modes. Eight of the g modes are precise multiples of the orbital frequency, to an accuracy greater than 3 σ. This is a signature of resonant excitation.
SPHOTOM – Package for an Automatic Multicolour Photometry
Authors: Parimucha Š. , Vaňko M. , Mikloš P.
Published: April 2012

We present basic information about package SPHOTOM for an automatic multicolour photometry. This package is in development for the creation of a photometric pipe-line, which we plan to use in the near future with our new instruments. It could operate in two independent modes, (i) GUI mode, in which the user can select images and control functions of package through interface and (ii) command line mode, in which all processes are controlled using a main parameter file. SPHOTOM is developed as a universal package for Linux based systems with easy implementation for different observatories. The photometric part of the package is based on the Sextractor code, which allows us to detect all objects on the images and perform their photometry with different apertures. We can also perform astrometric solutions for all images for a correct cross-identification of the stars on the images. The result is a catalogue of all objects with their instrumental photometric measurements which are consequently used for a differential magnitudes calculations with one or more comparison stars, transformations to an international system, and determinations of colour indices.
Hard X-ray and Optical Activity of Intermediate Polars
Authors: Gális Rudolf , Hric Ladislav , Kundra Emil
Published: April 2012

Intermediate polars represent a major fraction of all cataclysmic variables detected by INTEGRAL in hard X-rays. Nevertheless, only 25% of all known intermediate polars have been was detected in hard X-rays. This fact can be related to the activity state of these close interacting binaries. Multi-frequency (optical to X-ray) investigation of intermediate polars is essential to understand the physical mechanisms responsible for the observed activity of these objects.
Recent Spectral Observations of Epsilon Aurigae in the Near-IR
Authors: Iliev Lubomir
Published: April 2012

High resolution spectral observations of ϵ Aur were carried out in the near-IR spectral range. Observations were obtained with the Coudé-spectrograph of the 2m RCC telescope at National Astronomical Observatory Rozhen and cover all main phases of the current eclipse. Results revealed for the first time absorption components in O I and Ca II triplets and variations of N I lines. Estimation of the electron density was done using lines from the Paschen series of hydrogen.
Brown Dwarf Binaries
Authors: Allers Katelyn N.
Published: April 2012

Nearly 500 brown dwarfs have been discovered in recent years. The majority of these brown dwarfs exist in the solar neighborhood, yet determining their fundamental properties (mass, age, temperature & metallicity) has proved to be quite difficult, with current estimates relying heavily on theoretical models. Binary brown dwarfs provide a unique opportunity to empirically determine fundamental properties, which can then be used to test model predictions. In addition, the observed binary fractions, separations, mass ratios, & orbital eccentricities can provide insight into the formation mechanism of these low-mass objects. I will review the results of various brown dwarf multiplicity studies, and will discuss what we have learned about the formation and evolution of brown dwarfs by examining their binary properties as a function of age and mass.
Pre-Cataclysmic System V471 Tau with Confirmed Brown Dwarf and Suspected Extrasolar Planet
Authors: Hric Ladislav , Kundra Emil
Published: April 2012

We can show that analysis of the (O-C) diagram is a powerful method of detecting new bodies in binary systems. For this purpose we need very symmetric minima with precisely determined shapes. In the case of good covering by observations with high time resolution, it is possible to determine the times of such minima with sufficient accuracy. In the case of V471 Tau, the (O-C) diagram gave us residua which can be explained by the presence of a fourth body with substellar mass in the system.
Search for the Star-Planet Interaction
Authors: Krejčová Tereza , Budaj Ján , Koza Július
Published: April 2012

We analyse the chromospherical activity of stars with extrasolar planets and search for a possible correlation between the equivalent width of the core of the Ca II K line and orbital parameters of the planet. We found statistically significant evidence that the equivalent width of the Ca II K line reversal, which originates in the stellar chromosphere, depends on the orbital period Porb of the exoplanet. Planets orbiting stars with Teff < 5 500 K and with Porb < 20 days generally have much stronger emission than planets at similar temperatures but at longer orbital periods. Porb = 20 days marks a sudden change in behaviour, which might be associated with a qualitative change in the star-planet interaction.
An Extra-Solar Planet in a Double Stellar System: The Modelling of Insufficient Orbital Elements
Authors: Plávalová Eva , Solovaya Nina A. , Pittich Eduard M.
Published: April 2012

The modelling of the insufficient orbital elements of extra-solar planets (EPs) revolving around one component in a binary star system is investigated in the present paper. This problem is considered in the frame of the three-body problem using the analytical theory of Orlov & Solovaya (1998). In the general case, the motion is defined by the masses of the components and by the six pairs of the initial values of the Keplerian elements. For EPs, it is not possible to obtain the complete set of elements for the orbit, in particular, the ascending node and the angle of the inclination. So, it is possible the two different variants of orbital evolution of EPs depend on the initial conditions. In one case, the orbit is unstable. Using the stability conditions of Solovaya & Pittich (2004), which are presented by the angle of the mutual inclination of the orbits between the EP and distant star, we varied unknown angular elements and defined the regions with possible values of the elements for which the motion of EP stays stable. We applied these calculations to the particular specific EPs: HD19994b, HD196885Ab and HD222404b.
Polarimetry of Binary Stars and Exoplanets
Authors: Bjorkman Karen S.
Published: April 2012

Polarimetry is a useful diagnostic of asymmetries in both circumstellar environments and binary star systems. Its sensitivity to asymmetries in systems means that it can help to uncover details about system orbital parameters, including providing information about the orbital inclination. Polarimetry can probe the circumstellar and/or circumbinary material as well. A number of significant results on binary systems have been produced by polarimetric studies. One might therefore expect that polarimetry could similarly play a useful role in studies of exoplanets, and a number of possible diagnostics for exoplanets have been proposed. However, the application of polarimetry to exoplanet research is only in preliminary stages, and the difficulties with applying the technique to exoplanets are non-trivial. This review will discuss the successes of polarimetry in analyzing binary systems, and consider the possibilities and challenges for extending similar analysis to exoplanet systems.
Eclipsing Binaries Within Visual Ones: Prospects of Combined Solution
Authors: Zasche Petr
Published: April 2012

The study of eclipsing binaries as members of multiple systems can provide us important information about their origin, evolution, mutual inclination of the orbits, independent distance and mass determination, as well as the stellar multiplicity in general. We are carrying out a long-term photometric monitoring of several eclipsing binaries within the visual multiples and, besides the complete light curves, we are trying to detect the period changes due to the orbital motion around a common barycenter.

Systems like DN UMa, V819 Her, LO Hya, or VW Cep are typical examples of eclipsing binaries orbiting around the barycenter of the multiple system, while their respective periods are on the order of years or decades. However, the expected period variation is only hardly detectable and there is still uncertainty about which of the components is the eclipsing one. Precise spectroscopy would be of great benefit, but detecting the changes in the gamma velocity is still problematic, and spectral disentangling of such complicated systems like sextuple VV Crv (periods 1.46, 3.14, and 44.51 days) is also rather difficult. However, the detection of the changing depths of the eclipses in the latter system would be interesting.
Polarized Radiative Transfer Equation in Some Geometries of Elliptic Type
Authors: Freimanis Juris
Published: April 2012

A general method, which allows us to derive explicit expressions for the differential operator of stationary quasi-monochromatic polarized radiative transfer equation in Euclidean space, with piecewise homogeneous real part of the effective refractive index, is applied to ellipsoidal, oblate spheroidal, prolate spheroidal and elliptic conical coordinate systems.
Influence of Rotation Velocity Gradient on Line Profiles of Accretion Discs of CVs
Authors: Korčáková D. , Nagel T. , Werner K. , Suleimanov V. , Votruba V.
Published: April 2012

We show the influence of the Keplerian velocity shear on the line profiles of cataclysmic variable discs. The complete disc structure is taken into account. The radial disc structure follows the alpha disc approximation. Based on this assumption, the vertical structure is computed using the detailed non-LTE code AcDc. The obtained opacities and source functions are interpolated in the 2D grid, where the radiative transfer is calculated with the inclusion of the velocity field gradient.
Modeling of the Be Stars
Authors: Šejnová K. , Votruba V. , Koubský P.
Published: April 2012

The Be stars are still a big unknown in respect to the origin and geometry of the circumstellar disk around the star. Program shellspec is designed to solve the simple radiative transfer along the line of sight in three-dimensional moving media. Our goal was to develop an effective method to search in parameter space, which can allow us to find a good estimate of the physical parameters of the disk. We also present here our results for Be star 60 Cyg using the modified code.
ROCHE: Analysis of Eclipsing Binary Multi-Dataset Observables
Authors: Pribulla Theodor
Published: April 2012

Code ROCHE is devoted to modeling multi-dataset observations of close eclipsing binaries such as radial velocities, multi-wavelength light curves, and broadening functions. The code includes circular surface spots, eccentric orbits, asynchronous or/and differential rotation, and third light. The program makes use of synthetic spectra to compute observed UBVRIJHK magnitudes from the surface model and the parallax. The surface grid is derived from a regular icosahedron to secure more-or-less equal (triangular) surface elements with observed intensities computed from synthetic spectra for supplied passband transmission curves. The limb-darkening is automatically interpolated from the tables after each computing step. All proximity effects (tidal deformation, reflection effect, gravity darkening) are taken into account. Integration of synthetic curves is improved by adaptive phase step (important for wide eclipsing systems).

The code is still under development. It is planned to extend its capabilities towards low mass ratios and widely different radii of components to facilitate modeling of extrasolar planet transits. Another planned extension of the code will be modeling of spatially-resolved eclipsing binaries using relative visual orbits and/or interferometric visibilities.
The BINSYN Program Suite
Authors: Linnell Albert P.
Published: April 2012

The BINSYN program suite has been ported to a Linux-based operating system. The new program structure is a major revision from the original version and a public version is nearing completion. This paper describes research areas where the program suite is particularly applicabile.
Synthetic Spectra and Light Curves of Interacting Binaries and Exoplanets with Circumstellar Material: SHELLSPEC
Authors: Budaj Ján
Published: April 2012

Program SHELLSPEC is designed to calculate light-curves, spectra and images of interacting binaries and extrasolar planets immersed in a moving circumstellar environment which is optically thin. It solves simple radiative transfer along the line of sight in moving media. The assumptions include LTE and optional known state quantities and velocity fields in 3D. Optional (non)transparent objects such as a spot, disc, stream, jet, shell or stars may be defined (embedded) in 3D and their composite synthetic spectrum calculated. The Roche model can be used as a boundary condition for the radiative transfer. Recently, a new model of the reflection effect, dust and Mie scattering were incorporated into the code.

ϵ Aurigae is one of the most mysterious objects on the sky. Prior modeling of its light-curve assumed a dark, inclined, disk of dust with a central hole to explain the light-curve with a sharp mid-eclipse brightening. Our model consists of two geometrically thick flared disks: an internal optically thick disk and an external optically thin disk which absorbs and scatters radiation. Shallow mid-eclipse brightening may result from eclipses by nearly edge-on flared (dusty or gaseous) disks. Mid-eclipse brightening may also be due to strong forward scattering and optical properties of the dust which can have an important effect on the light-curves.

There are many similarities between interacting binary stars and transiting extrasolar planets. The reflection effect which is briefly reviewed is one of them. The exact Roche shape and temperature distributions over the surface of all currently known transiting extrasolar planets have been determined. In some cases (HAT-P-32b, WASP-12b, WASP-19b), departures from the spherical shape can reach 7-15%.
Search for Tidally Driven Anomalies in the Atmospheres of Am Stars
Authors: Stateva Ivanka , Iliev Ilian , Budaj Ján
Published: April 2012

We present here the systematic study of the chemical abundances of Am stars in order to search for possible abundance anomalies driven by tidal interaction in these binary systems. These stars were put into the context of Am binaries with 10 < Porb < 180 d and their abundance anomalies discussed in the context of possible tidal effects. There is clear anti-correlation of the Am peculiarities with v sin i. However, there seems to be also a correlation with eccentricity and orbital period.
Fundamental Parameters of Four Massive Eclipsing Binaries in Westerlund 1
Authors: Koumpia E. , Bonanos A. Z.
Published: April 2012

We present fundamental parameters of four massive eclipsing binaries in the young massive cluster Westerlund 1. The goal is to measure accurate masses and radii of their component stars, which provide much needed constraints for evolutionary models of massive stars. Accurate parameters can further be used to determine a dynamical lower limit for the magnetar progenitor and to obtain an independent distance to the cluster. Our results confirm and extend the evidence for a high mass for the progenitor of the magnetar.
Peculiarities in the Spectrum of the Early-type System MY Ser
Authors: Mayer P. , Drechsel H. , Brož M.
Published: April 2012

MY Ser is an eclipsing early-type contact system. Both components are of spectral type O6 III. Using ESO archive spectra, we show that the radial velocity of the third body, which contributes about half of the total luminosity, changed from 2006 to 2009. The line profiles of the eclipsing system have peculiar shapes and strengths; namely around conjunctions, they are affected by circumbinary matter.
The Role of Electron Scattering in Probing the Wind from the Hot Star in Symbiotic Binaries
Authors: Sekeráš Matej , Skopal Augustin
Published: April 2012

We modeled the broad wings of the OVI 1032,1038Å resonance lines and HeII 1640Å line in the spectra of some symbiotic stars by the electron-scattering process. We determined an empirical relationship between the emission measure of the symbiotic nebula and the electron optical depth. This allowed us to determine a contribution from the electron-scattering also to emission lines, which originate in a more extended, low density part of the nebula. For example, subtracting the electron-scattering contribution from the Hα line profile makes it possible to determine more precisely the mass loss rate via the wind from the hot star in symbiotic binaries.