High Velocity Gas in the Orion Nebula

Symposium - International Astronomical Union ◽

10.1017/s0074180900072090 ◽

1980 ◽

Vol 87 ◽

pp. 33-38

Author(s):

Nicholas Z. Scoville

Keyword(s):

High Velocity ◽

Center Of Mass ◽

High Spectral Resolution ◽

Collisional Excitation ◽

Orion Nebula ◽

Hii Region ◽

The Core ◽

Neutral Gas ◽

Infrared Wavelengths ◽

Co Emission

Observations at both millimeter and infrared wavelengths reveal energetic activity within the core of the Orion molecular cloud in the vicinity of the KL-BN cluster. New observations of the high velocity CO emission at 2.6-mm with improved angular resolution (HPBW = 44″) show that the source diameter averages 4 × 1017 cm and the center of mass is displaced 10-12″ north of the Kleinmann-Low nebula to a position close to the Becklin-Neugebauer object. The total mass of high velocity gas in the core region is ∼10 M⊙ (assuming 10% of the carbon is in CO); the present kinetic energy is 4 × 1047 ergs. Further evidence that BN may be the ultimate source of this energy is provided by high resolution infrared spectra which show both ionized and high temperature (Tk ≳ 3000 K) neutral gas in this source. CO bandhead emission (v = 2 → 0, 3 → 1, and 4 → 2) seen in BN is thought to arise from collisional excitation at high temperatures in a very dense (nH > 1010 cm−3) region only 1 AU in size. And high spectral resolution profiles of the Br α and γ recombination lines show that the HII region previously detected in BN apparently has motions over 100 km s−1.

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High Velocity Features in the Orion Nebula

The Astronomical Journal ◽

10.1086/118622 ◽

1997 ◽

Vol 114 ◽

pp. 2016 ◽

Cited By ~ 22

Author(s):

C. R. O'dell ◽

Patrick Hartigan ◽

John Bally ◽

Jon A. Morse

Keyword(s):

High Velocity ◽

Orion Nebula

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HST Images Do Not Support the Presence of Three High-Velocity, Low-Mass Runaway Stars in the Core of the Orion Nebula Cluster

The Astrophysical Journal ◽

10.1086/498450 ◽

2005 ◽

Vol 633 (1) ◽

pp. L45-L47 ◽

Cited By ~ 6

Author(s):

C. R. O'Dell ◽

Arcadio Poveda ◽

Christine Allen ◽

Massimo Robberto

Keyword(s):

High Velocity ◽

Orion Nebula ◽

The Core ◽

Low Mass ◽

Runaway Stars

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Galactic orbits of stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900105340 ◽

1966 ◽

Vol 25 ◽

pp. 93-97

Author(s):

Richard Woolley

Keyword(s):

Globular Cluster ◽

Potential Field ◽

High Velocity ◽

Velocity Vector ◽

Variable Stars ◽

The Sun ◽

Proper Motions ◽

Rr Lyrae ◽

The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

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Supernovae and interstellar gas dynamics

Symposium - International Astronomical Union ◽

10.1017/s0074180900100774 ◽

1967 ◽

Vol 31 ◽

pp. 117-119

Author(s):

F. D. Kahn ◽

L. Woltjer

Keyword(s):

Lower Limit ◽

High Velocity ◽

Gas Dynamics ◽

Interstellar Cloud ◽

Interstellar Gas ◽

Random Motions ◽

Relativistic Particles

The efficiency of the transfer of energy from supernovae into interstellar cloud motions is investigated. A lower limit of about 0·002 is obtained, but values near 0·01 are more likely. Taking all uncertainties in the theory and observations into account, the energy per supernova, in the form of relativistic particles or high-velocity matter, needed to maintain the random motions in the interstellar gas is estimated as 1051·4±1ergs.

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