Ring structures in Orion KL

Matveenko, L. I.; Diamond, P. J.; Graham, D. A.

doi:10.1134/1.1307554

Cited by 22 publications

(23 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Table 9 gives the absolute position of this H 2 O source, together with our methyl formate position and positions from other studies of nearby objects. Matveenko et al (2000) estimate a very low mass of 0.007 M for their H 2 O supermaser central source whose position is distinct from P1822/LBLS k. However, the proximity and youth of these two objects suggest that they might be a binary still in its forming phase.…”

Section: Main Methyl Formate Peak Mf1 (Compact Ridge)mentioning

confidence: 99%

“…This tends to confirm a scenario of MF production involving the release of molecules from ice mantles, either MF itself or a precursor (CH 3 OH). Four possible origins were identified for the excited H 2 emission and the MF production: shock from the "low-velocity" outflow from source I, shock from a bullet ejected during the supposed collision-explosion event 500 yr ago (Zapata et al 2009), action of the young forming star Parenago 1822/LBLS k, or from the nearby source (and possible companion of the star) responsible for the H 2 O supermaser (Matveenko et al 2000). We cannot conclude yet which of these four likely processes dominates the MF production, but all may have contributed.…”

Section: Discussionmentioning

confidence: 99%

“…Getman et al (2005) derive an age of 22 000 yr and a low mass of 0.26 M . Another nearby remarkable object is the H 2 O "Supermaser" identified and studied by Matveenko et al (2000), see also Demichev & Matveenko (2009) and Matveyenko et al (2007). Table 9 gives the absolute position of this H 2 O source, together with our methyl formate position and positions from other studies of nearby objects.…”

Section: Main Methyl Formate Peak Mf1 (Compact Ridge)mentioning

confidence: 99%

See 2 more Smart Citations

HCOOCH₃as a probe of temperature and structure in Orion-KL

Favre

Despois

Brouillet

et al. 2011

A&A

100

238

View full text Add to dashboard Cite

Context. The Orion Kleinmann-Low nebula (Orion-KL) is a complex region of star formation. Whereas its proximity allows studies on a scale of a few hundred AU, spectral confusion makes it difficult to identify molecules with low abundances. Aims. We studied an important oxygenated molecule, HCOOCH 3 , to characterize the physical conditions, temperature, and density of the different molecular source components. Methyl formate presents strong close rotational transitions covering a wide range of energy, and its emission in Orion-KL is not contaminated by the emission of N-bearing molecules. This study will help in the future 1) to constrain chemical models for the formation of methyl formate in gas phase or on grain mantles and 2) to search for more complex or prebiotic molecules. Methods. We used high-resolution observations from the IRAM Plateau de Bure Interferometer to reduce spectral confusion and to better isolate the molecular emission regions. We used twelve data sets with a spatial resolution down to 1.8 × 0.8 . Continuum emission was subtracted by selecting apparently line-free channels. Results. We identify 28 methyl formate emission peaks throughout the 50 field of observations. The two strongest peaks, named MF1 and MF2, are in the Compact Ridge and in the southwest of the Hot Core, respectively. From a comparison with single-dish observations, we estimate that we miss less than 15% of the flux and that spectral confusion is still prevailing as half of the expected transitions are blended over the region. Assuming that the transitions are thermalized, we derive the temperature at the five main emission peaks. At the MF1 position in the Compact Ridge we find a temperature of 80 K in a 1.8 × 0.8 beam size and 120 K on a larger scale (3.6 × 2.2 ), suggesting an external source of heating, whereas the temperature is about 130 K at the MF2 position on both scales. Transitions of methyl formate in its first torsionally excited state are detected as well, and the good agreement of the positions on the rotational diagrams between the ground state and the v t = 1 transitions suggests a similar temperature. The LSR velocity of the gas is between 7.5 and 8.0 km s −1 depending on the positions and column density peaks vary from 1.6 × 10 16 to 1.6 × 10 17 cm −2 . A second velocity component is observed around 9−10 km s −1 in a north-south structure stretching from the Compact Ridge up to the BN object, and this component is warmer at the MF1 peak. The two other C 2 H 4 O 2 isomers are not detected, and the derived upper limit for the column density is ≤3 × 10 14 cm −2 for glycolaldehyde and ≤2 × 10 15 cm −2 for acetic acid. From the 223 GHz continuum map, we identify several dust clumps with associated gas masses in the range 0.8 to 5.8 M . Assuming that the methyl formate is spatially distributed as the dust is, we find relative abundances of methyl formate in the range ≤0.1 × 10 −8 to 5.2 × 10 −8 . We suggest a relation between the methyl formate distribution and shocks as traced by 2.12 μm H 2 emission.

show abstract

Section: Main Methyl Formate Peak Mf1 (Compact Ridge)mentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Main Methyl Formate Peak Mf1 (Compact Ridge)mentioning

confidence: 99%

See 1 more Smart Citation

HCOOCH₃as a probe of temperature and structure in Orion-KL

Favre

Despois

Brouillet

et al. 2011

A&A

100

238

View full text Add to dashboard Cite

show abstract

“…There are, however, a handful of studied interstellar H 2 O maser sources that appear to be associated with circumstellar disks or rings rather than molecular outflows (Matveenko 1987;Cesaroni 1990;Fiebig et al 1996;Torrelles et al 1996;Berulis, Lekht, & Mendoza-Torres 1998;Torrelles et al 1998aTorrelles et al , 1998bHunter et al 1999;Shepherd & Kurtz 1999;Matveenko & Diamond 2000;Patel et al 2000;Lekht & Sorochenko 2001). These disks are thought to be the remnants of the molecular cloud cores out of which the stars formed (e.g., Shu, Adams, & Lizano 1987).…”

Section: Introductionmentioning

confidence: 99%

Expansion of the R4 H₂O Maser Arc near Cepheus A HW2

Gallimore

Cool

Thornley

et al. 2003

ApJ

View full text Add to dashboard Cite

We present new (2000 April) MERLIN observations of the H 2 O masers located near the protostar Cepheus A HW2. The MERLIN observations detect many of the structures found in earlier (1996) Very Long Baseline Array (VLBA) observations of Torrelles and collaborators, and the changed positions of these structures are compatible with the VLBA proper motions and astrometric uncertainties. The radius of curvature of the R4 structure of maser arcs appears to have grown by a factor of 2, and the displacement of the arcs between 1996 and 2000 is compatible with expansion about a common center. In addition, the MERLIN observations detect redshifted masers not previously found; taken with the newly discovered masers, the R4 structure now resembles patchy emission from an elliptical ring. We demonstrate that a simple bow shock model cannot simultaneously account for the shape and the velocity gradient of the R4 structure. A model involving a slow, hydromagnetic shock propagating into a rotating, circumstellar disk better describes the maser spot kinematics and luminosities. In this model, the central mass is 3 M , and we demonstrate that the mass of the disk is negligible in comparison. The expansion velocity of the postshock gas, $5 km s À1 , is slow compared to the shock velocity, v S $ 13 km s À1 , suggesting that the postshock gas is magnetically supported with a characteristic field strength of $30 mG. We speculate that the expanding maser rings R4 and R5 may be generated by periodic, instability-driven winds from young stars that periodically send spherical shocks into the surrounding circumstellar material.

show abstract

“…The surrounding matter accreting to the disk moved along arms and ejected to bipolar outflow. Tangential directions of the arms correspond to compact sources, brightness temperature of which are T b ≈ 10 12 K. The extra high temperature is result of amplification more than two orders of magnitude in the neighborhood [15,21]. Extra ordinary rotation of polarization is determined by different orientation polarization at nozzle outputs and velocities of outflows [23].…”

Section: Orion Klmentioning

confidence: 99%

Early VLBI in the USSR

Matveenko¹

2012

Proceedings of Resolving the Sky - Radio Interferometry: Past, Present and Future — PoS(RTS2012)

View full text Add to dashboard Cite

Ring structures in Orion KL

Cited by 22 publications

References 11 publications

HCOOCH₃as a probe of temperature and structure in Orion-KL

HCOOCH₃as a probe of temperature and structure in Orion-KL

Expansion of the R4 H₂O Maser Arc near Cepheus A HW2

Early VLBI in the USSR

Contact Info

Product

Resources

About

Ring structures in Orion KL

Cited by 22 publications

References 11 publications

HCOOCH3as a probe of temperature and structure in Orion-KL

HCOOCH3as a probe of temperature and structure in Orion-KL

Expansion of the R4 H2O Maser Arc near Cepheus A HW2

Early VLBI in the USSR

Contact Info

Product

Resources

About

HCOOCH₃as a probe of temperature and structure in Orion-KL

HCOOCH₃as a probe of temperature and structure in Orion-KL

Expansion of the R4 H₂O Maser Arc near Cepheus A HW2