# Tag Info

### How does the cepheid variables help in finding distance

Why not read his original paper? It's fairly short by today's standards, despite being such a monumental turning point in our understanding of the size and nature of the Universe. In short though, ...
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### Did Gaia actually generate complete light curves for 212 Cepheids in other galaxies?

Am I naive to think that it is necessary to build up a nice, complete light curve with dense points in time in order to use the photometry for precision distance calculations? No, the more I read ...
• 2,225
Accepted

### Pulsation Modes of Cepheids

Cepheid pulsations The basic description of the mechanism behind Cepheid pulsations is given here: The accepted explanation for the pulsation of Cepheids is called the Eddington valve,[38] or κ-...
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### Classification and discovery of stars

Cepheid variable stars and exoplanets transiting stars have very different light curves (the relation between brightness and time). Exoplanet light curve from NASA: Cepheid variable light curve from ...
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### How to find a Cepheid's pulsation period using its graph?

This graph is not the light curve of a cepheid. It is used to find the average brightness of the star, and from that, estimate its distance. The rate at which cepheids pulse is related to their ...
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### Did Gaia actually generate complete light curves for 212 Cepheids in other galaxies?

Casertano et al. used the period-luminosity (P-L) relation of Cepheid variables as a sanity check on Gaia DR1 parallaxes. They chose Cepheid variables within the Milky Way having parallaxes in TGAS (...
• 16.6k
Accepted

### Deriving phase of a pulsating star from list of Julian date values of observing brightness

INT refers to the floor function. So $\mathrm{INT}(x)$ is the largest integer not exceeding $x$. In this case, the function is used to get the fractional part of $\frac{\mathrm{HJD}-T_0}{P}$, i.e. ...
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### Stars in star clusters in SMC and LMC

Finally, after searching quite a deal, I found this paper which would aptly answer the question. The paper from 1999 published by Pietrzynski and Udalski in Acta Astronomica lists the Cepheids in the ...
• 810
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### Distance of extra-galactic Classical Cepheids

Since it seems you don't know the equations, I will try to keep it simple. However, just keep in mind that, in principle, there is no difference between Galactic and extragalactic Cepheids, in this ...
• 1,899
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### How to calculate a phase shift in the process of deriving Baade-Wesselinke distance?

It is admirable that you are tackling this type of problem as a high school student, but I really think that some of these topics are out of your grasp currently, partly because of the highly ...
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### Which software is appropriate to integrate radial velocity with respect to time

I'm not sure what you are actually trying to do. Radial velocity isn't generally measured, it is computed from the projected velocity. But if I take you at your word, that your raw data is radial ...
• 21
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### How does the Hubble Space Telescope "Drift and Shift"?

The "drift-and-shift" (DASH) mode was described in a paper by Momcheva et al. (2016), and works the way you supposed: a sequence of nearby images is taken using blind offsets without guide-star ...
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1 vote

### Observing cepheid variables in other galaxies

It is correct that we can't observation stars in other galaxies with the unaided eye. But with telescopes, we can see much more, including individual stars in other galaxies. We certainly have plenty ...
1 vote

### Stars in star clusters in SMC and LMC

Vizier is a good resource for finding catalogs. Searching for "SMC+cepheid" I found a related paper (Udalski et al. 1999) with additional data http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=J/AcA/...
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1 vote

### Pulsation Modes of Cepheids

[In addition to the answer already provided by Py-ser] In the body of a Cepheid, there is a regular or periodical variation of difference between the gravitational pressure and radiation pressure. ...
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