Sagittarius Project - Sagittarius.xls

The Sagittarius.xls EXCEL program is the first phase of the Sagittarius Project. The Sagittarius Project involves a simulation of 10 mini BH's which rotate around the BH which lies in centre of our Galaxy i.e. the constellation Sagittarius. For more detail select: Sagittarius Project For the source of the program select: Sagittarius.zip
This zip file consists of the program:
  1. Not available

1 Introduction

Sagittarius A* is a compact astronomical source at the center of the Milky Way. This location also harbours a Black Hole. For more detail select this link: https://en.wikipedia.org/wiki/Sagittarius_A*. Around this BH in Sagittarius A* rotate a certain number of Stars. It is the purpose of the Sagittarius Project to simulate these stars.
For more detail select this link: https://en.wikipedia.org/wiki/Sagittarius_A*#Orbiting_stars. The next 10 stars are considered:
id1 	a 	e 	i () 	omega  	w () 	Tp (yr) 	P (yr) 	Kmag 	q (AU) 	v (%c) 	dv      m0
S1 	0.5950 	0.5560 	119.14 	342.04 	122.30 	2001,800 	166.0 	14.70 	2160.7 	0.55 	0.03    12.40
S2 	0.1251 	0.8843 	133.91 	228.07 	66.25 	2018,379 	16.1 	13.95 	118.4 	2.56 	0.00	13.6
S4 	0.3570 	0.3905 	80.33 	258.84 	290.80 	1957,400 	77.0 	14.40 	1779.7 	0.57 	0.01    12.2
S6 	0.6574 	0.8400 	87.24 	85.07 	116.23 	2108,610 	192.0 	15.40 	860.3 	0.94 	0.00     9.2
S8 	0.4047 	0.8031 	74.37 	315.43 	346.70 	1983,640 	92.9 	14.50 	651.7 	1.07 	0.0     13.2
S9 	0.2724 	0.6440 	82.41 	156.60 	150.60 	1976,710 	51.3 	15.10 	793.2 	0.93 	0.02     8.2
S12 	0.2987 	0.8883 	33.56 	230.10 	317.90 	1995,590 	58.9 	15.50 	272.9 	1.69 	0.01     7.6
S13 	0.2641 	0.4250 	24.70 	74.50 	245.20 	2004,860 	49.0 	15.80 	1242.0 	0.69 	0.01    10.
S14 	0.2863 	0.9761 	100.59 	226.38 	334.59 	2000,120 	55.3 	15.70 	56.0 	3.83 	0.06    10.
S62     0.0905 	0.9760 	 72.76 	122.61 	 42.62 	2003,330 	 9.9 	16.10 	16.4 	7.03 	0.04    10.

                                             Table 1
The three most important parameters to consider at present are Tp, P and V. Tp is the epoch of pericentre passage, P is the orbital period in years and v is the pericentre speed in percent of the speed of light
This information is important because the parameter Tp in all cases is different, means that the speed v cannot be used directly as an initial state for all the stars.
For example: at Tp 2001,8 for S1 the speed v=0.55*C. However at that same instance the speed of all the other stars is unknown.
That is exactly what the program Sagitarrius.xls tries to solve: To calculate the initial parameters for a specific initial date.
For example: Suppose you want to calculate the initial parameters at TP2000, than this is okay for the stars S4, S8, S9 and S12 because each of TP values are before TP2000. To solve that you have to subtract the value of P (orbital period) from TP.

2. General Excel Program Description

To calculate the initial conditions at one specific date each star is handled individual and is considered a binary system together with the Black Hole.
The simulation performed is a 2D simulation using Newton's Law.
Each simulation in 2D requires the following parameters for each star: a, e, TP, v and m0
To do the same in 3D requires the folloing additional parameters: omega, inclination and w

The EXCEL program consists of 4 pages: Blad1, Sphere, Ellipse and JD Test.

  1. page Blad1 contains a database with all the parameters for the 10 stars but also for the planets. This is important to test certain program details for both environments.
  2. page Ellipse contains the simulation software for the 10 stars.
    The page contains one button marked Simulate. When the button Simulate is selected the program runs automatically.

3 Page Ellipse

3.1 Page Ellipse, Single Simulation, No Database update

The pupose of the 'single simultion' is to get a general idea what the Sagitarrius.xls program does. Only one mini BH is simulated.
Page Ellipse contains a certain # of Yellow cells which have to contain the folowing values:
  1. The Cell dt row 5 should be 1000.
  2. The Cell star# row 9 can have any value between 1 and 10, in order to select a star.
    In order to test enter # 10, which is star S62.
  3. The Cell auto mode row 11 should be 0.
    In that case the results are not stored in a dB file.
    Auto mode
    Picture 1
    • When Picture 1 is not selected the display shows the operating console when only one BH is simulated. In this particular case S62.
    • When Picture 1 is selected the display shows the operating console when all 10 mini BH's are simulated.

3.2 Page Ellipse, Complex Simulation, DataBase update

The purpose of this simulation is to simulate all then stars and and to store the results in a file.
In this case the Yellow Cells on Page Ellipse have to contain the folowing values:
  1. The Cell dt row 5 should be 1000.
  2. The Cell star# row 9 should be 0.
    The value of 0 means that all 10 stars are executed from from star #1 to star #10.
  3. The Cell auto mode row 11 should be 3.
    In that case the results are stored in a file.
  4. The following parameters are retrieved from the database in Blad1: m1, dist(a), e, star #, star name, P and TP
  5. These same parameters are stored in column 3 of Page Ellipse : m1 in row 2, dist(a) in row 3, e in row 4, star # in row 9, star name in row 10 , P in row 12 and TP in row 13.

3.3 Page Ellipse right half.

The right half of page ellipse contain the intermediate results of each simulation.
Auto mode
Picture 2
  • When picture 2 is not selected Picture 2 shows the results of S62
    row 2 shows the initial conditions when S62 is at aphelion.
    Column T shows the distance r1 from center of gravity, which is now at its maximum value.
    Column V shows the speed v1, which is now at its minimum value.
    row 8 shows the stuation when S62 is at perihelion. This was in 1993.
    Column T shows the distance r1, which is now at its minimum value.
    Column V shows the speed v1, which is now at its maximum value i.e. 7% of the speed of light.
    row 21 shows the stuation when S62 is at perihelion. This was in 2003.
  • When picture 2 is selected Picture 2 shows the results for Sagitarrius A* Column S shows the distance r0 from center of gravity, which is now at its maximum value.
    Column U shows the speed v0, which is now at its minimum value.
Picture 2 shows the result for star #10 or S62.
The most important information is in column T and V.
Column T shows the distance from the BH and Column V shows the speed of the star #10.
Column V is the easiest because it shows two waves. The higest speeds are in 1993 and 2003 when the star is at perihelion. Column T shows this shorest distance. This data is in agreement with Table 1

3.4 Page Elipse - Detailed discussion of S62

4 Excel Program description


Reflection part 1


Reflection part 2


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Created: 8 August 2020

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