The stellar photosphere–hydrogen ionization front interaction in classical pulsators: a theoretical explanation for observed period–colour relations

Susmita Das; Shashi M Kanbur; Earl P Bellinger; Anupam Bhardwaj; Harinder P Singh; Brett Meerdink; Nicholas Proietti; Anthony Chalmers; Ryan Jordan

doi:10.1093/mnras/staa182

The stellar photosphere–hydrogen ionization front interaction in classical pulsators: a theoretical explanation for observed period–colour relations

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa182 ◽

2020 ◽

Vol 493 (1) ◽

pp. 29-47

Author(s):

Susmita Das ◽

Shashi M Kanbur ◽

Earl P Bellinger ◽

Anupam Bhardwaj ◽

Harinder P Singh ◽

...

Keyword(s):

Theoretical Explanation ◽

Ionization Front ◽

Evolutionary Status ◽

Maximum Light ◽

Long Period ◽

Minimum Light ◽

Classical Cepheids ◽

Short Period ◽

Hydrogen Ionization ◽

Stellar Photosphere

ABSTRACT Period–colour and amplitude–colour (PCAC) relations can be used to probe both the hydrodynamics of outer envelope structure and evolutionary status of Cepheids and RR Lyraes. In this work, we incorporate the PCAC relations for RR Lyraes, BL Her, W Vir, and classical Cepheids in a single unifying theory that involves the interaction of the hydrogen ionization front (HIF) and stellar photosphere and the theory of stellar evolution. PC relations for RR Lyraes and classical Cepheids using the Optical Gravitational Lensing Experiment (OGLE-IV) data are found to be consistent with this theory: RR Lyraes have shallow/sloped relations at minimum/maximum light, whilst long-period (P > 10 d) Cepheids exhibit sloped/flat PC relations at minimum/maximum light. The differences in the PC relations for Cepheids and RR Lyraes can be explained based on the relative location of the HIF and stellar photosphere which changes depending on their position on the Hertzsprung–Russell diagram. We also extend our analysis of PCAC relations for type II Cepheids in the Galactic bulge, Large and Small Magellanic Clouds using OGLE-IV data. We find that BL Her stars have sloped PC relations at maximum and minimum light similar to short-period (P < 10 d) classical Cepheids. W Vir stars exhibit sloped/flat PC relation at minimum/maximum light similar to long-period classical Cepheids. We also compute state-of-the-art 1D radiation hydrodynamic models of RR Lyraes, BL Her and classical Cepheids using the radial stellar pulsation code in mesa to further test these ideas theoretically and find that the models are generally consistent with this picture. We are thus able to explain PC relations at maximum and minimum light across a broad spectrum of variable star types.

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Surface Brightness Radii and Distances of Cepheids and the Period-Radius Relationship

International Astronomical Union Colloquium ◽

10.1017/s0252921100109029 ◽

1985 ◽

Vol 82 ◽

pp. 38-42

Author(s):

W. P. Gieren

Keyword(s):

Surface Brightness ◽

Theoretical Models ◽

Long Period ◽

Classical Cepheids ◽

Short Period ◽

Absolute Magnitudes ◽

Considerable Support

Recently Gieren (1984) has derived accurate radii and distances of a sample of short-period classical Cepheids using the surface brightness (SB) method introduced by Barnes & Evans (1976). The results indicated that the period-radius (P-R) relationship obtained from SB radii might possess a slope close to the value of 0.82 defined by the Cepheids in clusters and associations (Fernie, 1983) and in conflict with the values obtained from Baade-Wesselink radii and from theoretical models (see Fernie, 1983). Since this finding would lend considerable support to the presently accepted absolute magnitudes of the cluster Cepheids, it was decided to obtain SB radii and distances of well-observed long-period Cepheids in order to strengthen the P-R relationship obtained from the SB technique.

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Discussion following the presentation by F. Deubner

International Astronomical Union Colloquium ◽

10.1017/s0252921100053240 ◽

1977 ◽

Vol 36 ◽

pp. 69-74

Keyword(s):

List Type ◽

The Sun ◽

Type Number ◽

Harmonic Motion ◽

Locally Excited ◽

Long Period ◽

Coherent Wave ◽

Short Period ◽

Global Modes

The discussion was separated into 3 different topics according to the separation made by the reviewer between the different periods of waves observed in the sun :1) global modes (long period oscillations) with predominantly radial harmonic motion.2) modes with large coherent - wave systems but not necessarily global excitation (300 s oscillation).3) locally excited - short period waves.

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Isolation and Analysis of Six timeless Alleles That Cause Short- or Long-Period Circadian Rhythms in Drosophila

Genetics ◽

10.1093/genetics/156.2.665 ◽

2000 ◽

Vol 156 (2) ◽

pp. 665-675

Author(s):

Adrian Rothenfluh ◽

Marla Abodeely ◽

Jeffrey L Price ◽

Michael W Young

Keyword(s):

Nuclear Translocation ◽

Phase Response Curve ◽

Fixed Number ◽

Constant Darkness ◽

Genetic Screens ◽

Protein Levels ◽

Long Period ◽

Short Period ◽

Molecular Oscillation ◽

New Alleles

Abstract In genetic screens for Drosophila mutations affecting circadian locomotion rhythms, we have isolated six new alleles of the timeless (tim) gene. Two of these mutations cause short-period rhythms of 21–22 hr in constant darkness, and four result in long-period cycles of 26–28 hr. All alleles are semidominant. Studies of the genetic interactions of some of the tim alleles with period-altering period (per) mutations indicate that these interactions are close to multiplicative; a given allele changes the period length of the genetic background by a fixed percentage, rather than by a fixed number of hours. The timL1 allele was studied in molecular detail. The long behavioral period of timL1 is reflected in a lengthened molecular oscillation of per and tim RNA and protein levels. The lengthened period is partly caused by delayed nuclear translocation of TIML1 protein, shown directly by immunocytochemistry and indirectly by an analysis of the phase response curve of timL1 flies.

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Wave Force Characteristics of Large-Sized Offshore Wind Support Structures to Sea Levels and Wave Conditions

Applied Sciences ◽

10.3390/app9091855 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1855

Author(s):

Youn-Ju Jeong ◽

Min-Su Park ◽

Jeongsoo Kim ◽

Sung-Hoon Song

Keyword(s):

Shallow Water ◽

Wave Height ◽

Wave Force ◽

Diffraction Effect ◽

Support Structures ◽

Sea Levels ◽

Irregular Wave ◽

Long Period ◽

Short Period ◽

Period Wave

This paper presents the results of wave force tests conducted on three types of offshore support structures considering eight waves and three sea levels to investigate the corresponding wave forces. As a result of this study, it is found that the occurrence of shoaling in shallow water induces a significant increase of the wave force. Most of the test models at the shallow water undergo a nonlinear increase of the wave force with higher wave height increasing. In addition, the larger the diameter of the support structure within the range of this study, the larger the diffraction effect is, and the increase in wave force due to shoaling is suppressed. Under an irregular wave at the shallow water, the wave force to the long-period wave tends to be slightly higher than that of the short period wave since the higher wave height component included in the irregular wave has an influence on the shoaling. In addition, it is found that the influence of shoaling under irregular wave becomes more apparent in the long period.

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Ultralong-period Cepheids: a possible primary distance indicator?

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312021552 ◽

2012 ◽

Vol 8 (S289) ◽

pp. 282-286 ◽

Cited By ~ 2

Author(s):

G. Fiorentino ◽

F. Annibali ◽

G. Clementini ◽

R. Contreras Ramos ◽

M. Marconi ◽

...

Keyword(s):

Spiral Galaxies ◽

Hubble Space Telescope ◽

Hubble Constant ◽

Variable Stars ◽

Evolutionary Status ◽

Stellar Systems ◽

Classical Cepheids ◽

Type Ia ◽

Distance Indicator ◽

Crucial Test

AbstractWe present a project that aims to provide a complete theoretical and observational framework for an as yet unexplored class of variable stars, the ultralong-period Cepheids (P longer than 80–100 days). Given their very high luminosities (MV up to −7 mag), with the Hubble Space Telescope we will be able to observe them easily in stellar systems located at large distances (~ 100 Mpc). This limit will be further increased, out to the Hubble flow (~ 350 Mpc), using future ground-based facilities such as the European Extremely Large Telescope. The nature of their pulsation is as yet unclear, as is their evolutionary status, which seems different from the central helium-burning phase generally associated with classical Cepheids. These objects have been found to cover a very large metallicity range, from [Fe/H] ~ −2 dex to solar values, and they are located in heterogeneous stellar systems, from dwarf to spiral galaxies. Once completely characterized, they could provide a crucial test, since they have been found in all Type Ia supernova host spiral galaxies that have been monitored for variability over long periods and that currently offer sound constraints on the estimated value of the Hubble constant.

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Reply to "Comment on 'Statistical Features of Short-Period and Long-Period Near-Source Ground Motions' by Masumi Yamada, Anna H. Olsen, and Thomas H. Heaton" by Roberto Paolucci, Carlo Cauzzi, Ezio Faccioli, Marco Stupazzini, and Manuela Villani

Bulletin of the Seismological Society of America ◽

10.1785/0120100210 ◽

2011 ◽

Vol 101 (2) ◽

pp. 919-924 ◽

Cited By ~ 1

Author(s):

M. Yamada ◽

A. H. Olsen ◽

T. H. Heaton

Keyword(s):

Ground Motions ◽

Statistical Features ◽

Long Period ◽

Short Period

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Epistatic and Synergistic Interactions Between Circadian Clock Mutations in Neurospora crassa

Genetics ◽

10.1093/genetics/159.2.537 ◽

2001 ◽

Vol 159 (2) ◽

pp. 537-543

Author(s):

Louis W Morgan ◽

Jerry F Feldman

Keyword(s):

Circadian Clock ◽

Neurospora Crassa ◽

Mutant Strain ◽

Temperature Compensation ◽

Double Mutant ◽

Synergistic Interactions ◽

Long Period ◽

Double Mutant Strain ◽

Short Period ◽

Compensation Mechanisms

Abstract We identified a series of epistatic and synergistic interactions among the circadian clock mutations of Neurospora crassa that indicate possible physical interactions among the various clock components encoded by these genes. The period-6 (prd-6) mutation, a short-period temperature-sensitive clock mutation, is epistatic to both the prd-2 and prd-3 mutations. The prd-2 and prd-3 long-period mutations show a synergistic interaction in that the period length of the double mutant strain is considerably longer than predicted. In addition, the prd-2 prd-3 double mutant strain also exhibits overcompensation to changes in ambient temperature, suggesting a role in the temperature compensation machinery of the clock. The prd-2, prd-3, and prd-6 mutations also show significant interactions with the frq7 long-period mutation. These results suggest that the gene products of prd-2, prd-3, and prd-6 play an important role in both the timing and temperature compensation mechanisms of the circadian clock and may interact with the FRQ protein.

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LONG-PERIOD SURFACE-RELATED MULTIPLE SUPPRESSION IN 2D MARINE SEISMIC DATA USING PREDICTIVE DECONVOLUTION AND COMBINATION OF SURFACE-RELATED MULTIPLE ELIMINATION AND PARABOLIC RADON FILTERING

10.32008/geolinks2021/b1/v3/30 ◽

2021 ◽

Author(s):

Pimpawee Sittipan ◽

Pisanu Wongpornchai

Keyword(s):

Seismic Data ◽

Seismic Reflection ◽

Petroleum Reservoirs ◽

The United States ◽

Multiple Reflections ◽

Long Period ◽

Predictive Deconvolution ◽

Short Period ◽

Marine Seismic ◽

Multiple Elimination

Some of the important petroleum reservoirs accumulate beneath the seas and oceans. Marine seismic reflection method is the most efficient method and is widely used in the petroleum industry to map and interpret the potential of petroleum reservoirs. Multiple reflections are a particular problem in marine seismic reflection investigation, as they often obscure the target reflectors in seismic profiles. Multiple reflections can be categorized by considering the shallowest interface on which the bounces take place into two types: internal multiples and surface-related multiples. Besides, the multiples can be categorized on the interfaces where the bounces take place, a difference between long-period and short-period multiples can be considered. The long-period surface-related multiples on 2D marine seismic data of the East Coast of the United States-Southern Atlantic Margin were focused on this research. The seismic profile demonstrates the effectiveness of the results from predictive deconvolution and the combination of surface-related multiple eliminations (SRME) and parabolic Radon filtering. First, predictive deconvolution applied on conventional processing is the method of multiple suppression. The other, SRME is a model-based and data-driven surface-related multiple elimination method which does not need any assumptions. And the last, parabolic Radon filtering is a moveout-based method for residual multiple reflections based on velocity discrimination between primary and multiple reflections, thus velocity model and normal-moveout correction are required for this method. The predictive deconvolution is ineffective for long-period surface-related multiple removals. However, the combination of SRME and parabolic Radon filtering can attenuate almost long-period surface-related multiple reflections and provide a high-quality seismic images of marine seismic data.

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Analysis of the eastern Adriatic sea-level extremes

10.5194/egusphere-egu21-5676 ◽

2021 ◽

Author(s):

Marija Pervan ◽

Jadranka Šepić

Keyword(s):

Sea Level ◽

Adriatic Sea ◽

Hot Spot ◽

Storm Surges ◽

Low Pressure ◽

Long Period ◽

Short Period ◽

Sea Level Oscillations ◽

Low Pass ◽

Level Height

The Adriatic Sea is known to be under a high flooding risk due to both storm surges and meteorological tsunamis, with the latter defined as short-period sea-level oscillations alike to tsunamis but generated by atmospheric processes. In June 2017, a tide-gauge station with a 1-min sampling resolution has been installed at Stari Grad (middle Adriatic Sea), the well-known meteotsunami hot-spot, which is, also, often hit by storm surges.&#160;Three years of corresponding sea-level measurements were analyzed, and 10 strongest episodes of each of the following extreme types were extracted from the residual series: (1) positive long-period (T > 210 min) extremes; (2) negative long-period (T > 210 min) extremes; (3) short-period (T < 210) extremes. Long-period extremes were defined as situations during which sea level surpasses (is lower than) 99.7 (i.e. 2) percentile of sea level height, and short-period extremes as situations during which variance of short-period sea-level oscillations is higher than 99.4 percentile of total variance[J1]&#160; of short-period series. A strong seasonal signal was detected for all extremes, with most of the positive long-period extremes appearing during November to February, and most of the negative long-period extremes during January to February. As for the short-period extremes, these appear evenly throughout the year, but strongest events seem to appear during May to July.All events were associated to characteristic atmospheric situations, using both local measurements of the atmospheric variables, and ERA5 Reanalysis dataset. It was shown that positive low-pass extremes commonly appear during presence of low pressure over the Adriatic associated with strong SE winds (&#8220;sirocco&#8221;), and negative low-pass extremes are associated to the high atmospheric pressure over the area associated with either strong NE winds (&#8220;bora&#8221;), or no winds at all. On the other hand, high-pass sea level extremes are noticed during two distinct types of atmospheric situations corresponding to both &#8220;bad&#8221; (low pressure, strong SE wind) and &#8220;nice&#8221; (high pressure, no wind) weather.It is particularly interesting that short-period extremes, of which strongest are meteotsunamis, are occasionally coincident with positive long-period extremes contributing with up to 50 percent to total sea level height &#8211; thus implying existence of a double danger phenomena (meteotsunami + storm surge).&#160;

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