What is the role of anisotropy in the dynamic modeling of star ?

Zainab Mohammadi

Yew-Chung Chak

Universiti Putra Malaysia

Mostafa Eidiani

Khorasan Electric Generation Company

Abiodun Olusola Omotayo

North-West University

Filippo Maria Denaro

Università degli Studi della Campania "Luigi Vanvitelli

30th Mar, 2016

Universidad de Salamanca

Find the attached file.

Anisotro
py.pdf
99.39 KB

30th Mar, 2016

National Defence Academy, Khadakwasla, Pune, India

Dear Prof. Herrera, since $p_t$ acts perpendicular to $p_r$, does it mean that $p_t$ will produce a rotational motion on the particles at interior? What will be the effect of anisotropy on a collapsing star?

30th Mar, 2016

Universidad de Salamanca

No, rotations are excluded by the spherical symmetry. (in the case you are considering such a case. The effect of anisotropy consists in the appearance of an additional "force" term, besides the pressure gradient.

30th Mar, 2016

Universidad de Salamanca

The above mentioned force term, of course, is directed along the radial direction.

31st Mar, 2016

Neeraj Pant

NATIONAL DEFENCE ACADEMY KHADAKWASLA PUNE INDIA

THANKS Prof Herrera for your prompt reply !

31st Mar, 2016

National Defence Academy, Khadakwasla, Pune, India

Prof. Herrera, that means, due to the presence of anisotropy, the collapse will be delayed ?

31st Mar, 2016

Universidad de Salamanca

It might be. It will depend on the type of anisotropy.

31st Mar, 2016

National Defence Academy, Khadakwasla, Pune, India

Thank you so much Prof. Herrera. This idea seems to agree with our new solution that represents a collapsing star with non-zero anisotropy. We have analysed the time evolution of all the physical quantities and found to delayed due to anisotropy. Again we found more anisotropy implies more delayed.

2nd Apr, 2016

Kali Charan

SSJ UNIVERSITY ALMORA

Dear sir, anisotropy may or may not delay the collapse rate it depends on type of anisotropy as said by Prof. Herrera i.e. radial pressure is greater or less than the tangential pressure.

2nd Apr, 2016

National Defence Academy, Khadakwasla, Pune, India

Here pr < pt, i.e. in TOV equation, the force due to anisotropy 2(pt-pr)/r > 0 and thus exert an outward force. Therefore it is clearly seen that positive anisotropy force will delay the collapsing possess.

5th Apr, 2016

G. Bothun

University of Oregon

I think everyone is forgetting that the interior of stars represents a complex plasma in its physics more than an ideal gas under hydrostatic equilibrium. Yes there is no LARGE SCALE asymmetry but there are important small scale effects.

1. We do know something about seismicity in the solar fluid through the solar helioseismology project. Bulk internal movements, which can move significant amounts of mass, can produce temporal anisotropies.

2. The role that magnetic fields play in the internal structures of stars is virtually unknown and may cause important effects

Also, in the latter part of stellar evolution when the core is degenerate there may be some important effects as well

15th Apr, 2016

D. R. K. Reddy

Andhra University

yes

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Harasit Kumar Paul

Bangabandhu Sheikh Mujib Medical University

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