Stellar Astrophysics - Science topic

the nature of time

Could it be that there is a fifth fundamental force, a 'hypergravity' that only manifests (i.e. becomes physically significant) at a large cosmological scale ?

The gravitational field of a quark is negligible compared to their electric charge and strong charge (color). But when a sufficient amount of quarks in the form of atomic nuclei come together they produce powerful gravitational fields.

In the same way at the mass scale of planets and stars the 'hypergravitational' force

is negligible and ordinary gravity (as well as electromagnetism and other forces) plays the predominant role.

But at a cosmological scale (for mass, energy or distance, i.e. millions of solar masses) the hypergravitational force will come into the play and explain astrophysical (sp. galactic) and cosmological phenomena which seem to require 'dark matter'.

Another aproach could be through dynamical systems. The water of the ocean behaves very differently from the water in a bathtub. Ultimately this must be explained by a different scale (also different set of 'negligibles') and different values for physical and chemical parameters of the same model.

Dear Researchers in the field :

Does anyone know what the KAGRA Gravitational Waves Observatory it's been up to ?

KAGRA announced at the end of last year (2019) that they were ready for the kick off. And that in February this year (2020) they were turn to the sky for the first (real) observations and be ready to joing the efforts of the LIGO-Virgo collaboration.

But I haven't hear anything about KAGRA since that time.

I'm sure they had to close due to the COVID-19 pandemic, probably since March.

But, now in December, almost the end of the year, I would have expected to hear news about Observatory.

Does anyone know what is it status nowadays ? Maybe the explanation is that the facilities kept shut down almost the whole year since the pandemic.

If someone know fresh news, I'll appreciate the sharing.

Best Regards all ! :)

To whom might be interested,

I have been thinking about prime numbers and how they might fit into our world, and this idea came to me that the primes might be constructed in a similar way to how elements fuse in stars.

To demonstrate my idea I wrote a short php script showing the construction of the first 25 primes. I have never seen anything like this before and I believe it is an original idea.

Would love to have some feedback on this from someone in number theory who have studied the primes.

Here is a link to the URL; https://www.gammaspectacular.com/steven/primes.php

Steven

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Question: since the findings of unmanned missions are many times what are gained by manned space missions why does the public care less about unmanned missions (which cost much less and go farther into space)?

How can the major findings of unmanned space missions be made more of interest?

The use of line abundance analysis using equivalent width and Kurucz model atmospheres in MOOG code is something done for chemical abundance analysis in stellar astronomy. However there is no material to guide through the procedure. Any resource with some examples of abundance analysis using this code?

Can we speak of a slight linear increase of the core density of sun-like stars during their stay in the main sequence ? As this is a period where gravitational effects are steadily balanced by the radiative pressure resulting from the progressive conversion of H into He. And the same with a bigger slope for the further period of conversion of He into C ?   

Under what natural processes could stellar formation have occurred after the initial singularity but prior to a cosmic inflation event?

Assume this is the scientific actuality, so it is not a question of if it could have occurred but how it could have occurred.

Assume  CR does not indicate any ongoing cosmic expansion. 

Thank you,

r

Tell me please who is researching the atmospheres of exoplanets, and the most of circulation?

For who conducted this research?

Does the existence of a developed theory of atmospheres on exoplanets depending on different astronomical conditions?

What organizations are engaged?

Where can I read about it?

Dolia Vadym.

In the light that we get from stars we discern certain lines belonging to the most abundant elements in those stars. Assume that we would pass the light from a star through a prism in order to disperse the spectrum, then isolate the hydrogen line(s).

Which one of the hydrogen lines is the most abundant in stars? And what are its properties: is the light in that line coherent light, or is it thermal light? Is it polarized?

We know that the equilibrium condition for neutron star. But I do not know in the case of hyperon star. Is it same or not?

Suppose the magnetic field in a region of space increases from 10⁻⁶ to 10⁻⁵ G over a period of 10⁷ yr. To what energy would nonrelativistic electrons and protons be accelerated if they moved perpendicular to the field and suffered no collisions? How does the final energy depend on the initial energy?

This picture was taken through my telescope (150/1400) from Tripoli (north of Lebanon). Briefly, the story of this picture is that when I was taking arbitrary pictures of the sky with my camera which was connected to my telescope, I saw something strange -maybe never seen before- (a group of blue stars surrounded by a group of red stars, attached photos). I thought that the blue dots were “Neptune” planet, but after focusing I have deduced that my thought was false because I saw a group of blue stars surrounded by a group of red stars. I didn't recognize what I saw but I was sure that it wasn't an artifact or an out of focus picture. To identify this picture, I have asked many specialists and amateurs of astronomy for help and explanation. None of them gave me a convincing answer. Some of them told me that it was a globular cluster, others talked about planetary nebula like ring nebula or owl nebula. Many specialists asked me about the coordinates of that location (RA/DEC) but the problem is that I didn't take into consideration these parameters and I can't review it now because I don't know its exact location in the sky. Keep in mind that there were no lights in the street, the place was totally obscured. The size of these points in the picture is not their actual size but red points appear only after enlarging it many times. So, before zooming there was only blue points and after zooming red and blue stars could be seen.

I am searching a listi of stellar types (F0,F1, F2, F3, F4, F5, F6, F7, F8, G0, G1,G2,G3,G4,G5,,G6,G7,G8,K0,K1,K2,K3,K4,K5,K6,K7,K8,M0,M1,M2,M3,M4,M5,M6,M7,M8) with temperature in kelvin and luminosity in solar units like these ones

I have used the KOSMA, JCMT and the SAAO optical telescopes all in an effort to understand the formation of stars i.e. massive stars.

Be that it may, one thing I have been asking myself of late, is -- what is it that astronomers reality measure, it is the frequency or the wavelength of the photon?

For all I know, when I use the KOSMA telescope, the KOSMA smart receiver actually measured the frequency of the photon and converted this into a wavelength using the equation c= wavelength X frequency.

I am asking this question in connection with the controversial issue of redshift of quasars. When astronomer measure the redshift of quasars, the telescopes that they use actually measure only the frequency of the photon -- am I right to think this or am I wrong? An answer to this is important in the work I am doing on issue of the distances to quasars.

Your answers will be of great benefit to my research.

As some of the research papers suggest that low FIP (below 10 KeV) elements get enhance by factor of 3-4 in Corona from Photosphere, while high FIP (above 10 KeV) elements don't show this characteristics.

Does this effect conclude anything about energy transfer from Photospere to Corona ?

Do you know a reference in the literature that gives straightforward conversion formulae between stellar color indices and effective temperatures for the broad range of spectral types and luminosities?

The central densities that are adopted for the initial, cold, WDs in this paper, seem to be a lot lower than those quoted in most papers on the stability of WDs near the Chandrasekhar limit. These say that non-rotating WDs become unstable at 1.39Msun but at densities of 2-3E13 kg/m^3, which seems to be an order of magnitude greater than adopted in the initial configurations here. Is there a simple explanation for this? Neglect of GR?

To my knowledge, the vast majority of white dwarfs and neutron star (WD+NS) systems appear as unresolved (am I right?), consequently WD+NS systems would be mixed up with isolated white dwarfs because of the magnitude/color dominance of the white dwarf companion. I bet that only in the cases of pulsar behavior the neutron star might give them away. However, not every neutron star is a pulsar, so I am wondering if there is a technique to unmask all the neutron stars that belong to close binary systems as WD+NS.

I'm interested in calculating the microturbulent velocity of iota Herculis (B3IV star) using the basic equation of Doppler broadening. The question is, can I modify the Doppler broadening (as indicated in the attachment) in order to include the macroturbulent velocity in the equation?

How can I find the list of Galactic AGB stars, including their distance?

Specifically, I like to know if alpha Herculis is THE closest AGB star to the Sun.

One thing is theory, but what do observations have to say about this?