NightshadowStarartcile

Nightshadow seen with the planet ‘Warrior’s Demise transiting across

Nightshadow – T4.5V Dwarf Companion star:

Mass .057143

73 J Mass

Stellar Radius .08 (1 Jupiter radius)

Radius 55,872.3 km

Luminosity .000008596

Temp in Kelvin 1101.6

Color deep reddish brown

Mean separation 18 AU

Orbital Period 141.811 years

Orbital Eccentricity .36

Closest separation 11.52 AU

Farthest separation 24.48 AU

Planets can’t survive: .0000624 AU

Inner system zone

1^st orbit .0009796 AU;

2^nd orbit .00156736;

3^rd orbit .00250776;

Inner Kuiper Belt: .095201 AU

Mid Kuiper Belt .172391 AU

Outer Kuiper Belt .223851 AU

Life Zone: inner: .00192975 AU

Outer: .0036022 AU

Optimum: .002573 AU

Basics about ‘Brown Dwarves’

“Brown Dwarves” are still an uncommon object, yet is becoming more common. This object is known simply as a “brown dwarf”. Ever since their discovery, these tiny objects have been filled with scientific work, theory, insight, study and speculation. Over the decades, much has been learned about these objects, as more are found every year. These objects are naked to the unaided eye, yet with a camera using a ‘near-infrared’ filter, one can spot them if one knows where to look. These dwarves are called sub-stellar objects since they have too little mass to maintain a hydrogen fusion process, and are objects that basically keep up it’s heat due to gravitational contraction, in other words, it shrinks. ‘Brown Dwarves’ come in two varieties, an L-dwarf and a T-dwarf. There are primary differences between the two, especially in density, temperature, spectra and chemical processes that occur within it. One thing about these objects is that they are in-between planets and stars in terms of how they work, since the cool with age like jovians. And so over time, a large ‘brown dwarf’ might start out as an L-dwarf with higher temperature, yet cool off and actually become cool enough to become a T-dwarf and then to planetary temperatures (under 1000 K). One major thing to note is that the larger the ‘brown dwarf’ the slower it cools down. To give an example of how slowly these larger dwarves cool down, take a dwarf that weighs 72 times that of Jupiter, it would be 9.5 Billion years old before that dwarf cooled to 1000K. Smaller dwarves, say of around 25 times the weight of Jupiter are small enough to barely even reach T-dwarf temperatures even at a young age of 1 Billion years, and so these dwarves will look more like Jupiter itself as they grow older. Brown dwarves do, like their low mass star big brothers, have magnetic fields within them, so that X-ray flares are emitted from these tiny dwarves as well. As for spectra, these dwarves can be seen by their dim red glow, emission of infra-red and uncommon X-ray flares. In the atmospheres of these dwarves are methane clouds due to the cool temperatures in the upper atmosphere of these objects. Some have even speculated the presence of liquid iron falling as rain due to severe weather that some theorists have speculated to exist.

First the L-dwarf is a very dim, deeply red dwarf that has a temperature of roughly 2100 K to 1300 K. The line between L-dwarf and M-star in terms of solar mass is .08 masses, which is about 85 Jupiter masses. Also a primary difference between it and an M-star is that a red dwarf shows strong Titanium oxide and Vanadium oxide lines, while the L-dwarf shows up with strong Hydride lines in its spectra. Hydrides are where hydrogen fuses with other chemicals, primarily seen as Iron hydride, Chromium Hydride, Magnesium Hydride and Calcium hydride. (FeH, CrH, MgH, CaH). Also, L-dwarves are known to show Alkali metals such as Sodium, Potassium, Cesium, and Rubidium. (Na I, K I, Cs I, Rb I). L-dwarves are near 75 Jupiter masses, nearly the 85 masses where the mainline M-star sequence begins. One thing that is agreed on is that at 65 Jupiter masses, the ‘brown dwarves’ can fuse both deuterium and lithium.

Secondly, the T-dwarf group is the cooler of the two varieties of ‘brown dwarf’. The lower end of the brown dwarves is generally thought to be 13 times the weight of Jupiter, since this is the limit of deuterium fusion. There have been isolated incidents of brown dwarves being smaller, even 8 times the mass, yet these dwarves will cool off very quickly and present little excitement of a lasting planetary system or even the possibility of life. The lower end of T-dwarves as far as temperature is still under debate, yet the border is generally thought as 800 K, the upper end is where it meets with L-dwarves at 1300 K.

Drem-B

T4.5 dwarf, that will reach T5 in another 500 million years of cooling, Drem is thought to have been hot enough to have been an L-dwarf for the first 3 Billion years of life, before going below the 1350K mark of becoming a T-dwarf. The dwarf will have gone thru roughly 17 Billion years of life before the temperature will reach 800K and then the dwarf will become more and more like Jupiter in appearance. So any habitable zone for this dwarf will be very stable for a long time, much like around the main star Drem.

Used with Celestia 1.4.1

Chris Laurel <claurel@www.shatters.net>

Clint Weisbrod <cweisbrod@cogeco.ca>

Fridger Schrempp <t00fri@mail.desy.de>

Bob Ippolito <bob@redivi.com>

Christophe Teyssier <chris@teyssier.org>

Hank Ramsey <hramsey@users.sourceforge.net>

Grant Hutchison <granthutchison@blueyonder.co.uk>