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Project MK27: Mon-R2



We have detected the water maser in Monoceros R2 IRS3 (near the Orion constellation).
So, what do we see with our 1 pixel radio telescope, well...this

Mon-R2-python-sum-1-and-2
Mon-R2-python-sum-1-and-2

It is a simple peak at 12.4km/s. This maser was difficult to capture; 2 of 14 trials were reasonable. Correction shift for the two vlsr plots was not needed.
Numerous identical profiles can be found on maserdb.org.
We cannot fine locate this water maser, but we can compare it with methanol measurements done on 6.7GHz.
Here we see 14 masers, located along a line.

Mon-R2-profile-Minier
Mon-R2-6.7GHz-profile-J2000-Minier

From the papers table 1, the OH reference location is J2000 Mon-R2 Nov. 98 06:07:47.9 -06:22:57.0; see paper below.
We can enter the individual OH velocity spots in a spreadsheet.

Mon-R2-excel-correlated-velocities-03

Mon-R2-Excel-correlated maser velocities

We see not a random velocity plot, but a sine like curve; indicating that these points are forming a circle.(sine fit tbd)
For the spacial points we can do the same.
With a Python script we can illustrate that by fitting an ellipse.

Mon-R2-6.7GHz-masers-on-ellipse

Mon-R2-6.7GHz masers on ellipse

Next we want to add the central calculated but invisible protostar.

Mon-R2-6.7GHz masers-on-ellipse-protostar

Mon-R2-6.7GHz masers-on-ellipse-protostar

Now we also want to add the H2O spot. There are a number of observations like in the next table.


AuthorRADECFrequency[GHz]Vlsr[km/s]
Tofani 06 07 47.8558-06 22 56.522412GHz --
Breen06 07 47.85-06 22 56.612GHz--
Minier06 07 47.90-06 22 57.06.6GHz --
Kim06 07 46.2-06 23 0812GHz--
Felli06 07 48.0-06 22 5712GHz--
Migenes06 07 47.8598-06 22 56.512712GHz--
Breen06 07 47.9-06 22 5712GHz12.7
Caswell06 07 48-06 22 56.712GHz10.9
Yang06 07 48.4-06 22 51.3 6.6GHz10.5

Table.1 - Mon-R2 H2O spot locations.

Often the methanol masers are formed in lower temperature regions and water masers in higher regions.
Higher temperatures are located closer to the radiating source.
Water masers are closer to the protostar. Our measurement gives a Vlsr of 12.4km/s.
This suggest to be near the center of the ring.
We select the 22GHz location vlbi result from Tofani.

Mon-R2-22GHz-sector-spot-01

Mon-R2-22GHz-sector-spot-01

So, it apeares that the water maser does not lie in the expected sector. It indicates more to be an outflow. However next one would expect bipolar outflow, but we see only one. So more investigations have to be done.

pdf1 :maser-location-table1--2000A+A___362_1093M
pdf2 :Tofani--1995A+AS__112__299T
pdf3 :OH-and-water-masers-profiles-in-Mon-R2--1976ApJ...204...21K
pdf4 :#Japan VLBI--0710.4872






Michiel Klaassen Februari 2023