Talk:Star
STAR PLACEMENT - General Notes[edit]
NOTE CONCERNING POSITIONS OF STARS AND CELESTIAL OBJECTS :
When comparing real-astronomical celestial object positions to the Traveller Map of Charted Space, it needs to be observed that the axes of the Charted Space Map appear to be tilted about 45o counter-clockwise from the correct position (i.e. "true" Coreward actually lies in the general direction of the Lesser Rift). If one makes that adjustment, about 70% of the named stars and celestial objects will fall roughly along their correct bearing. However, there are some exceptions in which the star in question lies in roughly the correct position relative to the Charted Space Map without the need to rotate the coordinate axes.
In general, if one is assigning the position of a Real-Universe star or celestial object to a Traveller Map hex, it should be acceptable if:
- 1) The object's longitude angle (θ) is within a 45o bearing-arc between the "true" coordinate axes and the Traveller Charted Space Map coordinate axes, and
- 2) The object's assigned distance from Terra on the hexmap falls somewhere between its true distance R in parsecs, and its 2D-projection onto the flat map as seen from above, found by Dproj = {R * cos(ɸ)}, where (ɸ) is the latitude angle. If desired, the distance above/below the plane can be determined by Z = {R * sin(ɸ)}.
ASTRONOMICAL NOTES:
Information about stars can be found at the following external websites:
Links (2019)[edit]
- EXTERNAL LINK: Has anyone (that you know of ) tried to Traveler map our actual galaxy based on star systems we know IRL?
- EXTERNAL LINK: The Known Star List for the Solomani Rim, Version 6.21 (14 Sep 02) by Harold Hale, Jo Grant, and Ben Lin
- - Maksim-Smelchak (talk) 11:00, 7 March 2019 (EST)
Links (2018)[edit]
- EXTERNAL LINK: YOUNG RED DWARFS THROW MEAN TANTRUMS. A LOT.
- - Maksim-Smelchak (talk) 07:21, 28 October 2018 (EDT)
Links (2017)[edit]
- EXTERNAL LINK: New evidence that all stars are born in pairs
- EXTERNAL LINK: https://www.space.com/22509-binary-stars.html
- - Maksim-Smelchak (talk) 09:13, 20 August 2017 (EDT)
Links (2016)[edit]
- EXTERNAL LINK: Kuiper Belt Glossary
- Maksim-Smelchak (talk) 13:10, 16 September 2016 (EDT)
Stellar Errata (2016)[edit]
External Link: Star Update Notes
- There's an old errata list for the sec files...
- 1. Change all primary Ds to Vs.
- 2. Change all VIs to Vs.
- 3. Star types K5 to M9 are not available with star size IV: change star size to V.
- 4. Star types A, F and G are extremely rare with star sizes II and III: change star size to V.
- 5. Star types M4V through M9V cannot have habitable worlds: subtract 6 from the decimal classification.
- 6. If two or more stars in the same system are size D, change the last one to size V.
- 7. Unless the primary star is size II, III, or IV, change remaining companion size D stars to size V.
White dwarfs usually have the prefix D:
- D (prefix) white dwarfs. Example: van Maanen 2 (DZ8)
From: Stellar_classification
- M0 D seems off. Maksim-Smelchak (talk) 00:18, 19 May 2015 (EDT)
- Older versions of Traveller, specifically Book 6, would generate a significant number of stars with type of "D". In the understanding of the time, this meant a Dwarf star. In current astrophysics is no such thing as a "M0 D" star. Either the star is a M0 V (called a dwarf star vs an Ib super-giant star), or it is a White Dwarf (per wikipieda). The latter is a problem because it would have had to have gone through it's complete stellar evolution, including expanding into giant size and cooked every planet in the system. T5 corrects this by changing every Type D start to a Type V. In this case the M0 D becomes an M0 V.
- There are also (rarely) stars of type VI. Again a historical gaming artifact generating star types which do not exist. These also should be given a type of "V". Tjoneslo (talk) 07:29, 19 May 2015 (EDT)
- Thanks, Tjoneslo! Maksim-Smelchak (talk) 07:40, 19 May 2015 (EDT)
- Actually, stellar Type VI does exist in the real world: it is known as a "Sub-Dwarf", and is a main-sequence star that is smaller (hence dimmer) and hotter than a normal main-sequence star (Type V) due to a lower overall metallicity (most likely because it was formed at an earlier period in the history of the Universe when there were fewer heavy elements). They are much less common than regular main-sequence stars, but there is one in Sol's back yard: Kapteyn's Star.
- - WHULorigan (talk) 07:57, 9 February 2018 (EST)
WHULorigan, I am hoping that T5SS will eventually tackle stars.
- - Maksim-Smelchak (talk) 10:01, 9 February 2018 (EST)
Smelchak Notes (2016)[edit]
External Link: SETI, Astrobiology and Red Dwarfs
{{InfoboxStar |name = |image = |spectral = |type = |multiple = |radius = |rrank = |lum = |mag = |lref = |lrworld = |lref2 = |lrworld2 = |temp = |mass = |mrank = |companion =
Instable systems[edit]
What about very recently formed stars that may still have much of their gas cloud, or which may be in the process of planet formation, with swarms of rocky planetoids colliding and aggregating?
Such systems would not be conventionally habitable, but on the other side they would be paradisical for resource extraction as the component pieces are yet in manageable sizes, and without much of a gravity well to transport up from.
Richards Notes[edit]
For the Stellar Frequencies Table, I still owe some references. They are forth coming and may cause my chart to change some. and an explanation of the calculations made to come up with the numbers I have. The number of stars was placed at roughly 200,000,000,000 as a compromise between the range of possible values of 100 to 400 billion stars. Then the number of estimated Black holes, Neutron stars and White Dwarfs was added to that number, as they were not part of the original estimate. Giving us the value of ~261,614,592,000
Stellar object frequencies[edit]
I noticed a typo/ small error in the Stellar Frequencies percentages. I have consulted https://en.wikipedia.org/wiki/Stellar_classification#/media/File:Stellar_Classification_Chart.png and the data suggests the correct percentage of Red Dwarf stars should be roughly 76.5%, so i will tweak the table.
