51 Ophiuchi
Encyclopedia
51 Ophiuchi is a young B-type star
, lying approximately 410 ly away in the constellation Ophiuchus
, northwest of the center of the Milky Way. It is notable for being "a rare, nearby example of a young planetary system just entering the last phase of planet formation".
and is probably
a planetary system in the late stages of formation. This system resembles Beta Pictoris
, a well known star with a large debris disk, in several ways:
spectral type, the presence of an edge-on disk with both gas and dust, and the presence of variable blue-shifted
absorption lines suggesting in-falling comets.
The distance to 51 Ophiuchi is much greater than the distance to Beta Pictoris
, and its debris disk is relatively compact. As a consequence, the disk around 51 Ophiuchi requires an interferometer to resolve, in contrast to that of Beta Pictoris, which has been observed using visual spectrum imaging. Recent observations of 51 Ophiuchi made with the Keck Interferometer Nuller at the W. M. Keck Observatory show that the disk has two components: a central cloud of large particles (exozodiacal dust
) surrounded by a much larger cloud of small silicate
particles extending to about 1,000 astronomical unit
s. The inner disk has a radius approximately four times the distance between the sun and the Earth, with a density of around 100,000 times that of the dust in our solar system.
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
, lying approximately 410 ly away in the constellation Ophiuchus
Ophiuchus
Ophiuchus is a large constellation located around the celestial equator. Its name is from the Greek "serpent-bearer", and it is commonly represented as a man grasping the snake that is represented by the constellation Serpens. Ophiuchus was one of the 48 constellations listed by the 2nd-century...
, northwest of the center of the Milky Way. It is notable for being "a rare, nearby example of a young planetary system just entering the last phase of planet formation".
Dust and gas disk
51 Ophiuchi has a disk of dust and gas that appears to be a young debris diskDebris disk
A debris disk is a circumstellar disk of dust and debris in orbit around a star. Sometimes these disks contain prominent rings, as seen in the image of Fomalhaut on the right. Debris disks have been found around both evolved and young stars, as well as at least one debris disk in orbit around a...
and is probably
a planetary system in the late stages of formation. This system resembles Beta Pictoris
Beta Pictoris
Beta Pictoris is the second brightest star in the constellation Pictor. It is located 63.4 light years from our solar system, and is 1.75 times as massive and 8.7 times as luminous as the Sun. The Beta Pictoris system is very young, only 8–20 million years old, although it is already in the main...
, a well known star with a large debris disk, in several ways:
spectral type, the presence of an edge-on disk with both gas and dust, and the presence of variable blue-shifted
Blue shift
A blueshift is any decrease in wavelength ; the opposite effect is referred to as redshift. In visible light, this shifts the colour from the red end of the spectrum to the blue end...
absorption lines suggesting in-falling comets.
The distance to 51 Ophiuchi is much greater than the distance to Beta Pictoris
Beta Pictoris
Beta Pictoris is the second brightest star in the constellation Pictor. It is located 63.4 light years from our solar system, and is 1.75 times as massive and 8.7 times as luminous as the Sun. The Beta Pictoris system is very young, only 8–20 million years old, although it is already in the main...
, and its debris disk is relatively compact. As a consequence, the disk around 51 Ophiuchi requires an interferometer to resolve, in contrast to that of Beta Pictoris, which has been observed using visual spectrum imaging. Recent observations of 51 Ophiuchi made with the Keck Interferometer Nuller at the W. M. Keck Observatory show that the disk has two components: a central cloud of large particles (exozodiacal dust
Exozodiacal dust
Exozodiacal dust is the exoplanetary analog of zodiacal dust, the 1-100 micrometre-sized grains of silicate dust that fill the plane of the solar system, especially interior to the asteroid belt. As for the zodiacal dust, these grains are probably produced by outgasing comets as well as by...
) surrounded by a much larger cloud of small silicate
Silicate
A silicate is a compound containing a silicon bearing anion. The great majority of silicates are oxides, but hexafluorosilicate and other anions are also included. This article focuses mainly on the Si-O anions. Silicates comprise the majority of the earth's crust, as well as the other...
particles extending to about 1,000 astronomical unit
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
s. The inner disk has a radius approximately four times the distance between the sun and the Earth, with a density of around 100,000 times that of the dust in our solar system.