HD 141569

Starbox short
name = HD 141569
epoch = J2000.0
equinox = J2000.0
constell = Libra
ra = RA|15|49|57.75
dec = DEC|-03|55|16.4
appmag_v = 7.11
absmag_v =
dist_ly = 320
dist_pc = 98
class = B9.5Ve
names = GSC 05026-00042, HIP 77542, SAO 140789
Simbad = HD+141569

HD 141569 is a blue-white dwarf star approximately 320 light-years away in the constellation of Libra. The primary star has two red dwarf companions (orbiting each other) at about nine arseconds. In 1999, a protoplanetary disk was discovered around the star. A gap in the disk speculate a possible extrasolar planet forming in the disk.

Planetary system

OrbitboxPlanet disk
disk = Inner disk
periapsis = 86
apoapsis = OrbitboxPlanet hypothetical
exoplanet = b
mass =
semimajor = 225
period =
eccentricity = OrbitboxPlanet disk
disk = Outer disk
periapsis = 250
apoapsis =

Protoplanetary disk

In January of 1999, NASA announced a protoplanetary disk around HD 141569. The Hubble Space Telescope showed that the disk appears to come in two parts (inner and outer). It superficially resembles the largest gap in Saturn's rings (known as the Cassini division).

The vast disk is 75 billion miles across (13 times the diameter of Neptune's orbit). The inner edge of the gap is 21 billion miles from the star. The relatively narrow gap lies approximately halfway between the inner and outer edges of the disk. Though already a fully formed star, HD 141569 is relatively young, probably only 1% through its lifetime as a stable star. The star is nearly three times more massive and 22 times brighter than the Sun.cite web |url=http://hubblesite.org/newscenter/archive/releases/1999/03/ |title=Hubble Views of Dust Disks and Rings Surrounding Young Stars Yield Clues |accessdate=2008-07-13 |work=Hubble Space Telescope |publisher=NASA |date=1999-01-08 ]

HD 141569 was first identified as a source that might have a disk in 1986 as a result of observations done with the Infrared Astronomical Satellite (IRAS). Thermal radiation emitted by the warmed dust was observed in images taken last June at the W. M. Keck Observatory.

Light from the central star which was reflected from dust particles in the disk was captured by Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) at a wavelength of 1.1 microns. At the distance of HD 141569, the crisp resolution of the telescope and camera combination reveals structures as small as 1 billion miles across. Dust disks surrounding newly forming stars are common, but only a small number of adult stars are known to have disks; of these, only a handful have been imaged. Astronomers believe these disks must form and/or be replenished when older rocks and debris collide and break up into small particles.

Possible planet

The gap in the disk leads to the conclusion of a protoplanet in formation around the star. The planet does not have to be in the gap, however. It could either be sweeping up the dust and rocks from the disk as it travels in its orbit around the star, or the gravity of the planet could knock the dust out of one part of the disk.

See also

* HR 4796
* Vega

References

External links

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