Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.arcetri.astro.it/~palla/ANDREAIMMAGINI/Stelle/9905a.pdf Дата изменения: Sun Feb 11 18:28:32 2001 Дата индексирования: Sat Dec 22 08:11:18 2007 Кодировка: Поисковые слова: dust disk

CoKu Tau1

DG Tau B

Haro 6-5B

500AU IRAS 04016+2610 IRAS 04248+2612 IRAS 04302+2247

Young Stellar Disks in Infrared Hubbl e Space Telescope · NICMOS
P RC99-05a · STScI OPO · D. Padgett (IPAC/Caltech), W. Brandner (IPAC), K . Stapelfeldt (JPL) and NASA


EMBARGOED UNTIL: 1:00 P.M. (EST) February 9, 1999

PHOTO NO.: STScI-PRC99-05a
NICMOS PEERS THROUGH DUST TO REVEAL YOUNG STELLAR DISKS
The following images were taken by NASA Hubble Space Telescope' Near-Infrared Camera s and Multi-Object Spectrometer. All of the objects are extremely young stars, 450 light-years away in the constellation Taurus. Most o f the nebulae represent small dust particles around the stars, which are seen because they are reflecting starlight. I n the color-coding, regions of greatest dust concentration appear red. All photo credits: D . Padgett (IPAC/Caltech), W. Brandner (IPAC), K.Stapelfeldt (JPL) and NASA Top left: CoKu Tau/1 Thi s image shows a newborn binary star system, CoK u Tau/1, lyin g at th e center of four "wings" of light extending as much as 75 billion miles from the pair. The "wings" outline the edges of a region in th e stars' dusty surroundings, which hav e been cleared by outflowin g gas. A thin , dark lane extends to the left and to righ t of th e binary, suggesting that a disk or ring o f dusty material encircles the two young stars. Top center: DG Tau B An excellent example of the complementary nature o f Hubble's instruments may be found by comparing the infrared NICM OS image of DG Tau B to the visible-light Wide Field and Planetary Camera 2 (WFPC2) imag e o f the sam e object. WFP C2 highlights the jet emerging from the system, while NICMOS penetrates some of the dust near the star to mor e clearly outline th e 50 billion-mile-long dust lan e (the horizontal dark band, which indicates the presence of a large disk forming around the infant star). The young star itself appears as the bright red spot at the corner of the V-shaped nebula. Top right: Haro 6-5B Thi s image of th e young star Haro 6-5B shows two bright regions separated by a dark lane. As seen in the WFPC2 image of the same object, the bright regions represent starlight reflecting from the upper and lower surfaces of th e disk, which is thicker at its edges than its center. However, the infrared view reveals the young star just above the dust lane. Bottom A very reddish forming left: I04016 young star still deep within the dusty cocoon from which i t formed is shown in this imag e of IR AS 04016+2610. The star is visible as a bright spot at th e base of a bowl-shaped nebula about 100 billion miles across at the widest point. The nebula arises from dusty material falling onto a circumstellar disk, seen as a partial dark band to th e left o f the star. Th e necklace of bright spots above the star is an imag e artifact.

Bottom cen ter: I04248 In this image of IRAS 04248+2612, the infrared eyes of NI CMOS peer through a dusty cloud to reveal a double-star system in formation. A nebula extends at least 6 5 billion miles in opposite directions from the twin stars, and i s illuminated b y them. This nebula w as formed fro m material ejected by the young star system. The apparent "pinching" of thi s nebula close to the binary suggests that a ring or disk of dust and gas surrounds the two stars. Bottom right: I04302 Thi s image shows IRAS 04302+2247, a star hidden from direct view and seen only by the nebula it illuminates. Dividing th e nebula in two is a dense, edge-on disk of dust and gas which appears as the thick, dark band crossing the center of the image. The disk has a diameter of 80 billion miles (15 times the diameter of Neptune's orbit), and ha s a mass comparable to the Solar Nebula, which gave birth to our planetary system. Dark clouds an d bright wisps above and below the disk suggest that it is still building up from infalling dust and gas.