Orbital Zone

Orbital Zone: Here for reference are the orbital zones for the various star types in Traveller.

• This data includes the Jump Diameter limit of the star and the Gravitic Drive Limit for the star.

Description (Specifications)

These are combined tables from various sources including T5, book 6 Scouts and Mega Traveller. Additionally, the data for O class stars was obtained from a website by Landon Noll

• A pink cell indicates the approximate size of the given star's jump shadow. Engaging a Jump drive is not safe within this area. Additionally, all incoming ships will be pulled out of jump outside of this area.
• Cells that have a grey border are outside the star's 10 diameter limit where gravitic drives can not function.
• A yellow cell indicates that the specified area is inside the star.
  • At this distance, unless using exotic technologies, any starship will be destroyed very quickly/instantaneously
• a cell with blue text indicates the approximate frost line for the given star.
• A dash "-" indicates that a planet will be vaporized with in that orbit, Likely a star ship as well.
  • Here the temperature is sufficient to vaporize metals. There is some delay while this happens.
  • Planets with atmospheres this far in will be White or Dark Redish-Grey.
• An "I" indicates Inner Zone.
  • Here any water will be present only as water vapour and, for many smaller worlds, that vapour will have escaped the atmosphere completely.
  • Planets with atmospheres will usually be deep blue, or showing some white or yellow clouds.
• An "H" indicates a habitable zone for most humanoid species.
  • Planets with atmospheres will usually be blue (water), or showing some white clouds.
• An "O" indicates Outer Zone.
  • Planets with atmospheres will be deep blue, rusty-pink or yellow (or combinations thereof) depending upon atmospheric composition.
• An "H-" indicates a hot Habitable zone, and a "H+" indicates a colder habitable zone. These values are used in T5. Replace H- with "I" and H+ with "O" for other editions of Traveller.
• WC stars are Wolf-Rayet stars of the carbon sequence (WC stars) These are an important cornerstone in the late evolution of massive stars before their core collapse. As core-helium burning, hydrogen-free objects with huge mass-loss, they are likely the last observable stage before collapse and thus promising progenitor candidates for type Ib/c supernovae.

NOTE: for Stellar classifications O and B the 10D Gravitic and 100D Jump Limits had to be calculated as they are not represented on any tables.

The Frost-Line (where ice melts to water or sublimes) generally lies 1-2 bands out from the "H+" band. It is at that line that cometary tails usually start to form.

Size IaO

The Hyper Giants table was calculated from data and can not be found in any of the Traveller source materials.

Size IaO Hyper Giants

Orbit	AU	O0	O5	B0	B5	A0	A5	F0	F5	G0	G5	K0	K5	M0	M5	M9	N0	N5	WC0	WC5
0	0.2	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*
1	0.4	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*
2	0.7	-	-	-	-	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*
3	1	-	-	-	-	-	*	*	*	*	*	*	*	*	*	*	*	*	-	-
4	1.6	-	-	-	-	-	-	-	*	*	*	*	*	*	*	*	*	*	-	-
5	2.8	-	-	-	-	-	-	-	-	*	*	*	*	*	*	*	*	*	-	-
6	5.2	-	-	-	-	-	-	-	-	-	*	*	*	*	*	*	*	*	-	-
7	10	-	-	-	-	I	I	I	I	-	*	*	*	*	*	*	-	*	-	-
8	20	-	-	I	I	I	I	I	I	I	I	*	*	*	*	*	I	*	-	-
9	40	-	I	I	I	I	I	I	I	I	I	I	I	I	*	*	I	*	I	I
10	77	I	I	I	I	I	I	I	I	I	I	I	I	I	*	*	I	I	I	I
11	154	I	I	I	I	H-	I	I	I	I	I	I	I	I	*	*	I	I	I	I
12	308	I	I	I	I	H	H-	H-	H-	H-	I	I	I	I	I	*	I	I	I	I
13	615	I	I	H-	H-	H+	H	H	H	H	H-	H-	H-	H-	I	*	I	I	I	I
14	1230	I	H-	H	H	O	H+	H+	H+	H+	H	H	H	H	I	I	I	I	I	H-
15	2500	H-	H	H+	H+	O	O	O	O	O	H+	H+	H+	H+	I	I	H-	I	H-	H
16	4900	H	H+	O	O	O	O	O	O	O	O	O	O	O	I	I	H	H-	H	H+
17	9800	H+	O	O	O	O	O	O	O	O	O	O	O	O	H-	I	H+	H	H+	O
18	19600	O	O	O	O	O	O	O	O	O	O	O	O	O	H	I	O	H+	O	O
19	39200	O	O	O	O	O	O	O	O	O	O	O	O	O	H+	H	O	O	O	O
20	78400	O	O	O	O	O	O	O	O	O	O	O	O	O	O	H+	O	O	O	O
21	156800	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O
22	313600	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O

It is worth noting that the jump shadow for a M9IaO star extends out to 3.413 light years. Fortunately, these stars are very rare. For reference Orbit 21 extends beyond the System Hex, and orbit 22 nearly encompasses the surrounding hexes. These rows were left in this table to show just how big these stars are.

Size Ia

Size Ia Bright Super Giants

Orbit No.	AU	O0	O5	B0	B5	A0	A5	F0	F5	G0	G5	K0	K5	M0	M5	M9	N0	N5
0	.2	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*
1	.4	-	-	*	*	*	*	*	*	*	*	*	*	*	*	*	*	*
2	.7	-	-	-	-	*	*	*	*	*	*	*	*	*	*	*	*	*
3	1	-	-	-	-	*	*	*	*	*	*	*	*	*	*	*	*	*
4	1.6	-	-	-	-	-	*	*	*	*	*	*	*	*	*	*	*	*
5	2.8	-	-	-	-	-	-	-	*	*	*	*	*	*	*	*	*	*
6	5.2	-	-	-	-	I	-	-	-	-	*	*	*	*	*	*	*	*
7	10	-	-	I	I	I	I	I	I	I	I	-	*	*	*	*	I	*
8	19.6	I	I	I	I	I	I	I	I	I	I	I	-	I	*	*	I	*
9	38.8	I	I	I	I	I	I	I	I	I	I	I	I	I	*	*	I	*
10	77.2	I	I	I	I	I	I	I	H-	I	I	I	I	I	I	*	I	I
11	154	I	I	I	H-	H-	I	I	I	I	I	I	I	I	I	*	I	I
12	307.4	I	I	I	I	H	H	H	H	H	I	I	I	I	I	*	H-	I
13	615	I	I	H	H	O	O	O	O	O	O	H	I	I	I	*	H	H-
14	1229.2	H	H	O	O	O	O	O	O	O	O	O	H	H	I	I	H+	H
15	2458	H	H	H+	O	O	O	O	O	O	O	O	O	O	I	I	O	H+
16	4915.6	O	O	O	O	O	O	O	O	O	O	O	O	O	I	I	O	O
17	9800	O	O	O	O	O	O	O	O	O	O	O	O	O	O	H	O	O

Size Ib

Size Ib Weaker Super Giants

Orbit No.	AU	O0	O5	B0	B5	A0	A5	F0	F5	G0	G5	K0	K5	M0	M5	M9
1	0.4	-	-	-	-	-	-	-	-	-	*	*	*	*	*	*
2	0.7	-	-	-	-	-	-	-	-	-	-	*	*	*	*	*
3	1.0	-	-	-	-	-	-	-	-	-	-	*	*	*	*	*
4	1.6	-	-	-	-	-	-	-	I	I	-	-	*	*	*	*
5	2.8	-	-	-	-	I	I	I	I	I	I	I	-	*	*	*
6	5.2	-	-	-	I	I	I	I	I	I	I	I	I	I	*	*
7	10.0	-	-	-	I	I	I	I	I	I	I	I	I	I	I	*
8	19.6	-	-	I	I	I	I	I	I	I	I	I	I	I	I	I
9	38.8	-	-	I	I	I	H-	H-	H-	H-	H-	H-	I	I	I	I
10	77.2	I	I	I	H-	H-	H	H	H	H	H	H	H-	H-	I	I
11	154.0	I	I	I	H	H	H+	H+	H+	H+	H+	H+	H	H	H-	H-
12	307.6	I	I	H-	H+	H+	O	O	O	O	O	O	H+	H+	H	H
13	614.8	H-	H-	H	O	O	O	O	O	O	O	O	O	O	H+	H+
14	1229.2	H	H	H+	O	O	O	O	O	O	O	O	O	O	O	O
15	2548.0	H+	H+	O	O	O	O	O	O	O	O	O	O	O	O	O
16	4915.6	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O

Size II

Size II Bright Giants

Orbit No.	AU	O0	O5	B0	B5	A0	A5	F0	F5	G0	G5	K0	K5	M0	M5	M9
1	0.4	-	-	-	-	-	-	-	-	-	-	-	*	*	*	*
2	0.7	-	-	-	-	-	I	I	I	I	I	I	-	*	*	*
3	1.0	-	-	-	-	I	I	I	I	I	I	I	I	*	*	*
4	1.6	-	-	-	-	I	I	I	I	I	I	I	I	I	*	*
5	2.8	-	-	-	I	I	I	I	I	I	I	I	I	I	*	*
6	5.2	-	-	I	I	I	I	I	I	I	I	I	I	I	I	I
7	10.0	-	I	I	I	I	H-	H-	H-	H-	H-	I	I	I	I	I
8	19.6	I	I	I	I	H-	H	H	H	H	H	H-	H-	I	I	I
9	38.8	I	I	I	I	H	H+	H+	H+	H+	H+	H	H	H-	H-	I
10	77.2	I	I	I	H-	H+	O	O	O	O	O	H+	H+	H	H-	H-
11	154.0	I	I	H-	H	O	O	O	O	O	O	O	O	H+	H	H
12	307.6	I	H-	H	H+	O	O	O	O	O	O	O	O	O	H+	H+
13	614.8	H-	H	H+	O	O	O	O	O	O	O	O	O	O	O	O
14	1229.2	H	H+	O	O	O	O	O	O	O	O	O	O	O	O	O
15	2548.0	H+	O	O	O	O	O	O	O	O	O	O	O	O	O	O
16	4915.6	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O

Size III

Size III Giants

Orbit No.	AU	O0	O5	B0	B5	A0	A5	F0	F5	G0	G5	K0	K5	M0	M5	M9
1	0.4	-	-	-	-	I	I	I	I	I	I	I	I	-	*	*
2	0.7	-	-	-	-	I	I	I	I	I	I	I	I	I	*	*
3	1.0	-	-	-	-	I	I	I	I	I	I	I	I	I	*	*
4	1.6	-	-	-	I	I	I	I	I	I	I	I	I	I	I	*
5	2.8	-	-	-	I	I	I	H-	H-	H-	I	I	I	I	I	I
6	5.2	-	-	-	I	I	H-	H	H	H	H-	H-	I	I	I	I
7	10.0	-	-	I	I	H-	H	H+	H+	H+	H	H	H-	H-	I	I
8	19.6	-	I	I	I	H	H+	O	O	O	H+	H+	H	H	H-	H-
9	38.8	I	I	I	H-	H+	O	O	O	O	O	O	H+	H+	H	H
10	77.2	I	I	I	H	O	O	O	O	O	O	O	O	O	H+	H+
11	154.0	I	I	H-	H+	O	O	O	O	O	O	O	O	O	O	O
12	307.6	I	H-	H	O	O	O	O	O	O	O	O	O	O	O	O
13	614.8	H-	H	H+	O	O	O	O	O	O	O	O	O	O	O	O
14	1229.2	H	H+	O	O	O	O	O	O	O	O	O	O	O	O	O
15	2548.0	H+	O	O	O	O	O	O	O	O	O	O	O	O	O	O
16	4915.6	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O

Size IV

Size IV Sub Giants

Orbit No.	AU	O0	O5	B0	B5	A0	A5	F0	F5	G0	G5	K0	K5	M0	M5	M9
0	0.2	-	-	-	-	-	I	I	I	I	I	I	na	na	na	na
1	0.4	-	-	-	-	I	I	I	I	I	I	I	na	na	na	na
2	0.7	-	-	-	-	I	I	I	I	I	I	I	na	na	na	na
3	1.0	-	-	-	I	I	I	I	I	I	I	H-	na	na	na	na
4	1.6	-	-	I	I	I	I	I	H-	H-	H-	H	na	na	na	na
5	2.8	-	-	I	I	I	H-	H-	H	H	H	H+	na	na	na	na
6	5.2	-	-	I	I	H-	H	H	H+	H+	H+	O	na	na	na	na
7	10.0	-	-	I	I	H	H+	H+	O	O	O	O	na	na	na	na
8	19.6	-	I	I	H-	H+	O	O	O	O	O	O	na	na	na	na
9	38.8	I	I	I	H	O	O	O	O	O	O	O	na	na	na	na
10	77.2	I	I	I	H+	O	O	O	O	O	O	O	na	na	na	na
11	154.0	I	I	H-	O	O	O	O	O	O	O	O	na	na	na	na
12	307.6	I	H-	H	O	O	O	O	O	O	O	O	na	na	na	na
13	614.8	H-	H	H+	O	O	O	O	O	O	O	O	na	na	na	na
14	1229.2	H	H+	O	O	O	O	O	O	O	O	O	na	na	na	na
15	2548.0	H+	O	O	O	O	O	O	O	O	O	O	na	na	na	na
16	4915.6	O	O	O	O	O	O	O	O	O	O	O	na	na	na	na

Size V

Size V Main Sequence

Orbit No.	AU	O0	O5	B0	B5	A0	A5	F0	F5	G0	G5	K0	K5	M0	M5	M9
0	0.2	-	-	-	-	I	I	I	I	I	H-	H-	H	H	H+	H+
1	0.4	-	-	-	-	I	I	I	I	H-	H	H	H+	H+	O	O
2	0.7	-	-	-	-	I	I	I	I	H-	H+	H+	O	O	O	O
3	1.0	-	-	-	I	I	I	I	H-	H	O	O	O	O	O	O
4	1.6	-	-	-	I	I	I	H-	H	H+	O	O	O	O	O	O
5	2.8	-	-	-	I	I	H-	H	H+	O	O	O	O	O	O	O
6	5.2	-	-	I	I	H-	H	H+	O	O	O	O	O	O	O	O
7	10.0	-	I	I	I	H	H+	O	O	O	O	O	O	O	O	O
8	19.6	-	I	I	H-	H+	O	O	O	O	O	O	O	O	O	O
9	38.8	I	I	I	H	O	O	O	O	O	O	O	O	O	O	O
10	77.2	I	I	I	H+	O	O	O	O	O	O	O	O	O	O	O
11	154.0	I	I	H-	O	O	O	O	O	O	O	O	O	O	O	O
12	307.6	I	H-	H	O	O	O	O	O	O	O	O	O	O	O	O
13	614.8	H-	H	H+	O	O	O	O	O	O	O	O	O	O	O	O
14	1229.2	H	H+	O	O	O	O	O	O	O	O	O	O	O	O	O
15	2548.0	H+	O	O	O	O	O	O	O	O	O	O	O	O	O	O
16	4915.6	O	O	O	O	O	O	O	O	O	O	O	O	O	O	O

Size VI

Size VI Sub Dwarf

Orbit No.	AU	O0	O5	B0	B5	A0	A5	F0	F5	G0	G5	K0	K5	M0	M5	M9
0	0.2	-	-	-	-	I	I	I	I	H-	H-	O	O	O	O	O
1	0.4	-	-	-	-	I	I	I	H-	H	H	O	O	O	O	O
2	0.7	-	-	-	I	I	I	H-	H	H+	H+	O	O	O	O	O
3	1.0	-	-	-	I	I	H-	H	H+	O	O	O	O	O	O	O
4	1.6	-	-	-	I	I	H	H+	O	O	O	O	O	O	O	O
5	2.8	-	-	I	I	H-	H+	O	O	O	O	O	O	O	O	O
6	5.2	-	-	I	I	H	O	O	O	O	O	O	O	O	O	O
7	10	-	I	I	H-	H+	O	O	O	O	O	O	O	O	O	O
8	20	I	I	I	H	O	O	O	O	O	O	O	O	O	O	O
9	40	I	I	I	H+	O	O	O	O	O	O	O	O	O	O	O
10	77	I	I	H-	O	O	O	O	O	O	O	O	O	O	O	O
11	154	I	I	H	O	O	O	O	O	O	O	O	O	O	O	O
12	308	I	H-	H+	O	O	O	O	O	O	O	O	O	O	O	O
13	615	H-	H	O	O	O	O	O	O	O	O	O	O	O	O	O
14	1230	H	H+	O	O	O	O	O	O	O	O	O	O	O	O	O
15	2500	H+	O	O	O	O	O	O	O	O	O	O	O	O	O	O

Size D

Alternatively: Size VII

Size D White Dwarf

Orbit No.	AU	O	B	A	F	G	K	M
0	0.2	na	H	O	O	O	O	O
1	0.4	na	O	O	O	O	O	O

History & Background (Dossier)

Traveller, now known as Classic Traveller, was founded in 1977 CE, a long time ago in a Galaxy not so far away... We know it's not so far away because it features Earth. It's now 2019 CE, and a world of change has occurred in the scientific fields that perform astronomy, astrography, celestial observation, space sciences, Xenobiology, and practically every other field involved with science fiction in one way or another. The breakneck pace of new discoveries in space science, mean that it is very hard to keep an old-fashioned hard copy RPG abreast of the latest discoveries. Referees, authors, players, and fans just have to do their best to customize their game to their tastes and the latest news.

References & Contributors (Sources)

	This article was originally developed for wiki.travellerrpg.com by William Richards 2026, all rights reserved.

This list of sources was used by the Traveller Wiki Editorial Team and individual contributors to compose this article. Copyrighted material is used under license from Mongoose Publishing or by permission of the author. The page history lists all of the contributions.

• Book 6 by Marc Miller
• Megatraveller Referee's Manual
• Traveller 5.10, Book 3 Worlds and Adventures
• EXTERNAL LINK: Stellar Classification Table - Sorted by HR Class by Landon Noll (Fair Use) last accessed on Oct 11, 2019
• Author: William Richards