Related papers: Welcome back, Polaris the Cepheid
A collection of active photometric observations over the last half decade, archival data from the past 120 years, radial velocity observations from 1984, and recent monitoring through a pro-am collaboration reveal that the 9th magnitude F9…
AU Pegasi is a pulsating star in a spectroscopic binary system with an orbital period of 53.26 days. Between 1960 and 1990 an extremely rapid period increase was observed in the value of the pulsation period, but in the last 15 years the…
Comparison of the old observations of Cepheids in the Small Magellanic Cloud from the Harvard data archive, with the recent OGLE and ASAS observations allows an estimate of their period changes. All of matched 557 Cepheids are still…
We report on the surprising recent discovery of strong FUV emissions in two bright, nearby Classical Cepheids from analyses of FUSE archival observations and one of our own approved observations just prior to the failure of the satellite.…
In prior work, conducted since 2017, two celestial pointing directions have been observed to be associated with the measurement of anomalous high counts of narrow bandwidth, short duration, polarized radio frequency pulse pairs. The prior…
Periodic modulations are seen in normal period pulsars ($P >$ 0.1 sec) over timescales ranging from a few seconds to several minutes. Such modulations have usually been associated with the phenomenon of subpulse drifting. A number of recent…
Hydrodynamic models of short--period Cepheids were computed to determine the pulsation period as a function of evolutionary time during the first and third crossings of the instability strip. The equations of radiation hydrodynamics and…
Pulsars with periods more than 0.4 seconds in the declination range -9o < decj < 42o and in the right ascension range 0h < r.a.< 24h were searched in parallel with the program of interplanetary scintillations monitoring of a large number of…
Measurements of rates of period change of Classical Cepheids probe stellar physics and evolution. Additionally, better understanding of Cepheid structure and evolution provides greater insight into their use as standard candles and tools…
The quantity and quality of satellite photometric data strings is revealing details in Cepheid variation at very low levels. Specifically, we observed a Cepheid pulsating in the fundamental mode and one pulsating in the first overtone with…
The search of pulsars in monitoring observations being carried out for 5 years using LPA LPI radio telescope was done in 96 spatial beams covering daily 17,000 square degrees. Five new pulsars were detected. Candidates into pulsars were…
A recently presented HST/FGS parallax measurement of the Polaris system has been interpreted as evidence for the Cepheid Polaris Aa to be pulsating in the second overtone. An age discrepancy between components A and B has been noted and…
The Cepheid Period-Luminosity law is a key rung on the extragalactic distance ladder. However, numerous Cepheids are known to undergo period variations. Monitoring, refining, and understanding these period variations allows us to better…
Polaris is the nearest Cepheid to us and as such holds a special place in our understanding of Cepheids in general and the Leavitt Law. In the past couple of decades, we have learned many new things about the star as a Cepheid and as the…
We report the discovery using the Parkes radio telescope of binary millisecond pulsars in four clusters for which no associated pulsars were previously known. The four pulsars have pulse periods lying between 3 and 6 ms. All are in circular…
We derive the astrometric orbit of the photo-center of the close pair alpha UMi AP (=alpha UMi Aa) of the Polaris multiple stellar system. The orbit is based on the spectroscopic orbit of the Cepheid alpha UMi A (orbital period of AP: 29.59…
At the highest levels of pulsar timing precision achieved to date, experiments are limited by noise intrinsic to the pulsar. This stochastic wideband impulse modulated self-noise (SWIMS) limits pulsar timing precision by randomly biasing…
Y~Ophiuchi (Y~Oph) is a classical Cepheid reported to be as dim as a Cepheid of about half its pulsation period, and exhibits a low radial velocity and light-curves amplitude. Our objective is to conduct hydrodynamical pulsation modeling of…
Pulsar timing at the Mt Pleasant observatory has focused on Vela, which can be tracked for 18 hours of the day. These nearly continuous timing records extend over 24 years allowing a greater insight into details of timing noise, micro…
PSR J1518+4904 is a recently discovered 40.9~ms pulsar in an 8.6 day, moderately eccentric orbit. We have measured pulse arrival times for this pulsar over 1.4~yr at several radio frequencies, from which we have derived high precision…