[BRIEF NOTE] On the latest landmark of our glorious future in space (2)

[rfmcdonald]

My previous post dealt with the success of space probes. This post deals with the astonishing power and accuracy of ground- and space-based telescopes. Where once fans of science fiction imagined that fleets of probes and manned vehicles would be needed to discover planets from afar, the current generation of telescopes does this quite well. Centauri Dreams' post on the discovery of two very dim nearby brown dwarfs.

The two brown dwarf discoveries — WISE J0254+0223 and WISE J1741+2553 — are at estimated distances of 15 and 18 light years respectively. Their strong infrared signature and their extremely faint appearance at visible wavelengths attracted the team’s attention, and both show the high proper motion across the sky that flags nearby stellar objects. The team was able to use the Large Binocular Telescope (LBT) in Arizona to determine spectral type and distance more accurately. Interestingly, both objects fit into the category of T-type brown dwarfs, at the boundary of the still not well defined class of Y-type brown dwarfs.

The first brown dwarf was only found in 1995; now, the universe is turning out to be dense with them. There may even be brown dwarf objects closer to our planetary system than nearby Alpha Centauri.

The (un)known Solar neighbors. The stars are shown with symbols of different sizes and colours, roughly corresponding to their real sizes and spectral types. Most stars in the Solar neighborhood are red dwarf stars of spectral type M (in the middle of the figure) with surface temperatures of slightly more than 2000 Kelvin. Proxima, our nearest known neighbor, also belongs to this class. The number of brown dwarf discoveries (almost all with spectral types L and T, and surface temperatures below 2000 K) is already higher than the number of white dwarfs (shown as small white dots at the top). The two nearest brown dwarfs, epsilon Indi Ba and Bb, the discovery of which was reported by the AIP in 2003 and 2004, and the newly found objects are marked. (Credit: AIP).

And more will be coming