J.-E. Solheim

UiT The Arctic University of Norway · Department of Physics and Technology

In order to evaluate how much Total Solar Irradiance (TSI) has influenced Northern Hemisphere surface air temperature trends, it is important to have reliable estimates of both quantities. Sixteen different estimates of the changes in Total Solar Irradiance (TSI) since at least the 19th century were compiled from the literature. Half of these estim...

To evaluate the role of Total Solar Irradiance (TSI) on Northern Hemisphere (NH) surface air temperature trends it is important to have reliable estimates of both quantities. 16 different TSI estimates were compiled from the literature. 1/2 of these estimates are low variability and 1/2 are high variability. 5 largely-independent methods for estima...

The Sun’s activity constantly varies in characteristic cyclic patterns. With new material and new analyses, we reinforce the old proposal that the driv- ing forces are to be found the planetary beat on the Sun and the Sun’s mo- tions around the center of mass. This is a Special Issue published on Pattern Recognition in Physics where various aspects...

Among geologists, astronomer and oceanographers very strong and severe critics are raised to the main message of the April 27 issue. Experimental tests have failed to endorse the basic concept of the hypothesis of man-made global warming. There are no real reasons to expect a continual warming of the Arctic peaking in ice-free conditions by 2040,...

A review of observations and theoretical developments for the AM CVn type stars since the previous workshop is given. For AM CVn itself, line profile variations are interpreted as a sign of an elliptical disk in a permanent superoutburst state. This object also shows ''flares`` and UV-wind profiles. A new family member, EC 15330-14, with almost ide...

The spectrum of AM CVn shows no definite sign of a secondary star, but through black body calculations of the spectra of the primary, disc and secondary objects, we find that if a one-temperature model for the secondary is assumed, a secondary which is cooler than 5000 K may be present without being seen in the spectrum. There is some excess flux i...

A preliminary report of the analysis of multicolor data obtained in February 1994 for AM CVn is presented. The light curve has been observed in the UBVRI passbands over three nights with 20 % coverage. Temporal spectroscopy of the data shows that the 525 and 350 s modulations of the light curve have amplitudes, phases and shapes which are identical...

Preliminary results of the analysis of the XCOV4 campaign data in March and April 1990 for AM CVn are presented. The pulse spectrum has five harmonics of the undetected fundamental period 1051 s. In addition, sidebands are observed with a 21 microHz spacing, always on the high-frequency side. It is not possible to explain these observations as g-mo...

The WET groups in Europe co-operate on many levels. With a grant from the European Union, instrument development, joint observing campaigns and some short-time support for young scientists have been possible. At the moment the grant has expired, but instrument development continues with own funds, concentrating on the development of high-speed CCD...

Recent observations at the NOT telescope clearly show that PG 1618+563 is a new member of the EC14026 class of sdB pulsating stars (Kilkenny et al. 1997, O'Donoghue et al. 1999). The very good quality of the non-filtered data allows to detect an amplitude modulation effect with a beat period of about 1.2 hours, which is consistent with the presence...

For all the AM CVn objects we observe harmonic structure in the FT of their light curves. From recent advances in the theory of accretion discs we now can relate the harmonic structures to physical structures in the discs. Numerical simulations provide us with tools to interpret the pattern resulting from the tidal disc responses and non-linear cou...

We study the splitting of pulsations of the ZZ Ceti (DAV) white dwarf G 117--B15A using 96 h time series photometric data obtained with the Whole Earth Telescope in March 1990. We find that all the modes, except the main, have fine structure, but not according to the predictions of simple rotational or magnetic splitting of non-radial g-mode pulsat...

RXJ 2117+3412 is a transition object between the planetary nebulae and the white dwarfs. The central star is a pulsating PG 1159 type star. We summarize here the results of the campaigns organized between 1992 and 1994. We identify about 50 modes, most of them probably belonging to l = 1. The derived mass of the star is 0.57 Msun. Its distance can...

A prototype CCD photometer has been designed and assembled in Tromso, and tested at the Nordic Optical Telescope with the XCOV 17 target PG 1336-018 as a test object. Our new instrument uses a windowed readout technique to create an arbitrary number of virtual channels in the CCD field, and a sampling rate that can be pushed down to 1 Hz, thereby o...

We present a preliminary analysis of the data collected during the 1999/1 (XCOV17) Whole Earth Telescope (WET) campaign to observe the pulsating subdwarf B star PG 1336-018. Since PG 1336-018 is an HW Vir type eclipsing binary, our hope is to use the known orbital period, assume a tidally locked system, and search for rotationally split modes. To t...

A summary of the results on PQ Gem based on WET observations conducted in February 1996 is presented. The 13.9 min spin period of the white dwarf in the system and the orbital side-band at 14.5 min have been detected unambiguously. Searches for other periods in the system gave negative results.

The pulsating DA white dwarf R 548 was observed for 46 h in October 1993 in an eight-site campaign. New peaks near the known doublets in the Fourier transform are found.

The Whole Earth Telescope collaboration is build solidly on the interest of the participants. One of the goals of the collaboration is to produce a high signal to noise, as continuous as possible, light curve for a selected target. During the nearly 15 years of existence the operation of the network has been based on what the members have been able...

Account of the extinction in the Earth's atmosphere is an important part of the WET light curve reduction procedures. Usually, WET observations are not corrected for the second order extinction effects: the dependence of the extinction coefficient on spectral type and on air mass (the Forbes effect). The ignorance of these effects does not change s...

The Whole Earth Telescope (WET) saw first light in 1988. It was invented by scientists from the Astronomy Department, University of Texas at Austin. The idea was to generate a world-wide network of cooperating astronomical observatories to obtain uninterrupted time-series measurements of some variable stars. The technological goal was to resolve th...

The goal of the WET collaboration is to produce a photometric light curve as continuous and accurate as possible, given the weather and technical constraints. In order to join light curves from different observers, it is important that all observer's clocks are accurately synchronized with Universal Time, and with a precision substantially better t...

Experiment with small greenhouses, adding various amounts of CO2. No extra heating is observed.

The variation of the ice edge position is analyzed and compared with the total solar irradiance (TSI). Autocorrelation of the wavelet spectrum shows stationary periods close to the orbital periods of Saturn, Uranus and Neptun, suggesting a relation.

Total solar irradiance (TSI) is the primary quantity of energy that is provided to the Earth. The properties of the TSI variability are critical for understanding the cause of the irradiation variability and its expected influence on climate variations. A deterministic property of TSI variability can provide information about future irradiation var...

Planets influence on solar variability

Variations of the ice edge has been analyzed and stationary periods close to the orbital periods of Saturn, Uranus and Neptun are found. They appear also in total solar irradiation series. This indicates that there may be a connection between the planets, the Sun, and the position of the ice edge.

On January 7, 2013, there was a major solar flare. It occurred in direct connection with a triple planetary conjunction of Venus, Earth and Jupiter. This is in line with the theory of a solar response to planetary beat. The simultaneous aurora, magnetometer and tidal signals observed at Tromsø are reviewed, and a commensurability between the Sun- V...

The international journal of Pattern Recognition in Physics was a good journal that might have become a renowned forum for important scientific papers. Its termination due to a straightforward conclusion on solar variability in relation to climate change is not only to be regretted as an unreasonable constraint on academic freedom but also excoriat...

The Sun’s activity constantly varies in characteristic cyclic patterns. With new material and new analyses, we reinforce the old proposal that the driving forces are to be found in the planetary beat on the Sun and the Sun’s motions around the center of mass. This is a Special Issue published on Pattern Recognition in Physics where various aspects...

The idea that planetary effects may modulate, or even control solar variability is old; having been investigated by Rudolf Wolf from 1859 until his death in 1893. Many further efforts to measure and explain the possible mechanisms for planetary solar effects have been made by researchers at frequent intervals through the years. Despite this it has...

The best method for identification of planetary forcing of the Earth's climate is to investigate pe-riodic variations in climate time series. Some natural frequencies in the Earth climate system seem to be synchronized to planetary cycles, and amplified to a level of detection. The response by the Earth depends on location, and in global averaged s...

The Schwabe frequency band of the sunspot record since 1700 has an average period of 11.06 years and contains four major cycles, with periods of 9.97, 10.66, 11.01 and 11.83 years. Analysis of the O-C residuals of the timing of solar cycle minima reveals that the solar cycle length is modulated by a secular period of about 190 years and the Gleissb...

In a collection of research papers devoted to the problem of solar variability and its origin in plan-etary beat, it is demonstrated that the forcing function originates from gravitational and inertial effects on the Sun from the planets and their satellites. This conclusion is shared by nineteen co-authors.

Introduction to our special issue on Patterns in Solar variability, their origins and terrestrial impacts. Investigations of the hypothesis of a planetary affect on solar variability confirms strong correlations between planetary motion and solar activity changes. These are visible in Earth's paleological history proxy records and contemporary dire...

Callebaut et al. (2012)'s claim that Scafetta (2010)'s results about a correlation between 20-year and 60-year temperature cycles and the orbital motion of Jupiter and Saturn were not confirmed by Humlum et al. (2011) is erroneous and severely misleading. Also Callebaut et al. (2012)'s absolute claim that a planetary influences on the Sun should be...

Using data series on atmospheric carbon dioxide and global temperatures we investigate the phase relation (leads/lags) between these for the period January 1980 to December 2011. Ice cores show atmospheric CO2 variations to lag behind atmospheric temperature changes on a century to millennium scale, but modern temperature is expected to lag changes...

Based on 22 years of observations, we obtained the frequency and amplitude variations of the 7 largest amplitude modes of the GW Vir star PG 0122+200. We find that these variations occur on a much shorter time scale and with larger amplitude than predicted by theoretical evolutionary models in which the frequency variations only result from the sta...

Relations between the length of a sunspot cycle and the average temperature in the same and the next cycle are calculated for a number of meteorological stations in Norway and in the North Atlantic region. No significant trend is found between the length of a cycle and the average temperature in the same cycle, but a significant negative trend is f...

Analytic climate models have provided the means to predict potential impacts on future climate by anthropogenic changes in atmospheric composition. However, future climate development will not only be influenced by anthropogenic changes, but also by natural variations. The knowledge on such natural variations and their detailed character, however,...

PG 1351+489 is one of the 20 DBVs - pulsating helium-atmosphere white dwarf stars - known and has the simplest power spectrum for this class of star, making it a good candidate to study cooling rates. We report accurate period determinations for the main peak at 489.334 48 s and two other normal modes using data from the Whole Earth Telescope (WET)...

PG 2303+243 is a cool DA variable (also called ZZ Ceti) star with a rich pulsation spectrum and variable amplitudes. A mini-campaign involving six observatories yielded time-resolved photometric measurements of PG 2303+243 during the period 2004 September 5–20. A duty cycle of 35 per cent was achieved. We detected 24 possible independent frequencie...

Context: The PG 1159 pre-white dwarf stars experiment a rapidly cooling phase with a time scale of a few 106 years. Theoretical models predict that the neutrinos produced in their core should play a dominant role in the cooling, mainly at the cool end of the PG 1159 sequence. Measuring the evolutionary time scale of the coolest PG 1159 stars could...

Climate development with possible anthropogenic effects occurs on a background of natural climatic variations, which may be considerable, and especially in the Arctic. Natural climate variations however remain poorly understood, although they remain important for discriminating between natural and anthropogenic influences on current climate change....

The long temperature series at Svalbard (Longyearbyen) show large variations, and a positive trend since its start in 1912. During this period solar activity has increased, as indicated by shorter solar cycles. The temperature at Svalbard is negatively correlated with the length of the solar cycle. The strongest negative correlation is found with l...

AM CVn stars are the final outcome of a fine tuned binary star evolution. They are hydrogen deficient and have orbital periods less than 65 minutes, which make them possible detectable sources for Gravitational Wave (GW) radiation. Mass is transferred between a low mass star with a variable degree of degeneracy to a heavier white dwarf. The Sloan...

KPD 1930+2752 is a short-period pulsating subdwarf B (sdB) star. It is also an ellipsoidal variable with a known binary period of 2.3 h. The companion is most likely a white dwarf and the total mass of the system is close to the Chandresekhar limit. In this paper, we report the results of Whole Earth Telescope (WET) photometric observations during...

AM CVn stars are the outcome of a fine-tuned binary star evolution pathway. They are helium-rich and their binary orbital periods are less than 65 minutes. They evolve through one or two common envelope (CE) events, which are difficult to model. Observations of AM CVn stars are important to understand the CE phase. Thanks to intensive observing cam...

Context. A search programme for pulsating subdwarf B stars was conducted with the Nordic Optical Telescope on La Palma over 59 nights between 1999 and 2009. Aims: The purpose of the programme was to significantly extend the number of rapidly pulsating sdB stars to better understand the properties of this new group of variable compact stars. Methods...

The table contains all the sdB stars observed during the NOT survey that were not identified as pulsators. It provides coordinates, details of the photometric sequences, and on the variability for each object. (1 data file).

This white paper briefly describes the astrophysics of ultra-compact binaries, with emphasis of the challenges and opportunities in the next decade.

Observation of g-mode pulsations in the variable pre-white dwarf (GW Virginis) stars provides a unique means to probe their interiors and to study the late stages of stellar evolution. Multisite campaigns have in several cases proved highly successful in decoding pre-white dwarf light curves. Three previous attempts to untangle the pulsation spectr...

We report our analysis of the stability of pulsation periods in the DAV star (pulsating hydrogen atmosphere white dwarf) ZZ Ceti, also called R548. On the basis of observations that span 31 years, we conclude that the period 213.13 s observed in ZZ Ceti drifts at a rate dP/dt ≤ (5.5 ± 1.9) × 10-15 s s-1, after correcting for proper motion. Our resu...

Ultraviolet observations using the Solar Blind Channel on the Hubble Space Telescope provide light curves and low-resolution spectra of three pulsating white dwarfs in the cataclysmic variables SDSS J013132.39-090122.3, SDSS J161033.64-010223.3, and SDSS J220553.98+115553.7. The UV light curves show enhanced pulsation amplitudes over those from sim...

The cataclysmic variable SDSS J015543.40+002807.2 is confirmed to be a magnetic system of the AM Herculis type. With an orbital period of 87.13 minutes, it is also the shortest period eclipsing Polar known. Monitoring with XMM-Newton finds a high-state light curve dominated by a single X-ray-emitting accretion pole located slightly prograde of the...

We report the results of a synthetic spectral analysis of HST STIS spectra of the AM CVn-type cataclysmic variable CP Eri obtained when the system was in quiescence. The FUV spectrum is best fitted by a helium-dominated, hybrid composition (DBAZ) white dwarf with Teff ~ 17,000 ± 1000 K, log g ~ 8, He/H abundance ratio by number ~1000, metallicity Z...

We report on the analysis of 436.1 hrs of nearly continuous high-speed photometry on the pulsating DB white dwarf GD358 acquired with the Whole Earth Telescope (WET) during the 2006 international observing run, designated XCOV25. The Fourier transform (FT) of the light curve contains power between 1000 to 4000 microHz, with the dominant peak at 123...

We have observed with continuous photometry some hydrogen-deficient Planetary Nebula Nuclei (PNNs) with bipolar envelopes to search for pulsations, and to characterize the pulsations found. Our sample includes the "hybrid PG 1159" stars Abell 43 and NGC 7094 which are shown to have extremely long period g-mode pulsations between 38 and 101 min, dri...

The pre-white dwarf pulsators of PG 1159 type, or GW Virginis variable stars, are in a phase of rapid evolution towards the white dwarf cooling sequence. The rate of change of their nonradial g-mode frequencies can be measured on a reasonably short time scale. From a theoretical point of view, it was expected that one could derive the rate of cooli...

PG 1159-035, a pre-white dwarf with T_eff=140,000 K, is the prototype of both two classes: the PG1159 spectroscopic class and the DOV pulsating class. Previous studies of PG 1159-035 photometric data obtained with the Whole Earth Telescope (WET) showed a rich frequency spectrum allowing the identification of 122 pulsation modes. In this work, we us...

After the initial discoveries fifteen years ago, over 200 extrasolar planets have now been detected. Most of them orbit main-sequence stars similar to our Sun, although a few planets orbiting red giant stars have been recently found. When the hydrogen in their cores runs out, main-sequence stars undergo an expansion into red-giant stars. This expan...

While Abell 43 is entering the PG 1159 instability strip, in fact as an "hybrid-PG 1159" nucleus of a planetary nebula, PG 0122+200 presently defines its red edge. So these two stars define the limits of the instability strip along the evolutionary sequence from the planetary nebula nuclei to the pre-white dwarf PG 1159 stars. We describe the new o...

Because PG 2303+243 had not been observed since 1992, we have arranged the mini-campaign of six observatories on PG 2303+243 in 2004 Sep. 5-21 for the more detailed frequency analysis of variations. The amplitudes of the most frequencies change even during the one night and some frequencies can disappear or appear in one year. Probably it is resona...

We analyse the frequencies shown by the recently discovered pulsating sdB star PG 1657+416. It has at least four frequencies in the range 6.8--7.8 mHz, which are used to constrain the log g value of the star. Moreover, we derive an estimate of the radial order of the modes on the basis of the observed frequency distribution.

Based on 24h high speed photometry of the hybrid PG 1159 star Abell 43, we have detected 6 sighificant pulsations with periods between 2380 s and 6075 s. A short (4h) run on the almost spectroscopic twin NGC 7094 central star resulted in detection of 3 low amplitude pulsations with periods between 2000 s and 5000 s. The results are close to predict...

Context.The variable pre-white dwarf PG 1159 stars (GW Vir) are $g$-mode non-radial pulsators. Asteroseismology puts strong constraints on their global parameters and internal structure. PG 0122+200 defines the red edge of the instability strip and its evolutionary timescale is predicted to be dominated by neutrino emission. Its study offers the op...

In this article we present the O-C diagram of the hot subdwarf B pulsating star HS2201+2610 after seven years of observations. A secular increase of the main pulsation period, Pdot=(1.3+-0.1)x10**(-12), is inferred from the data. Moreover, a further sinusoidal pattern suggests the presence of a low-mass companion (Msini=~3.5 Mjup), orbiting the hot...

Context: Since the discovery in 1997 of stellar oscillations in some B-type hot subdwarfs (sdBs), much effort is being made both observationally and theoretically to characterize this new group of pulsating objects. Aims: To increase the number of members of such pulsators and to perform a theoretical analysis of new pulsating stars. Methods: The N...

Single DAV pulsating white dwarfs are known to show non-radial g-mode pulsations with periods around 50-1400s and have temperatures in the specific range of 11,000-12,500K. With the discovery of several pulsating white dwarfs in the accreting close binary systems of cataclysmic variables, it is possible to probe the effects of mass transfer and acc...