Volume 403, Number 3, June I 2003
|Page(s)||1095 - 1100|
|Section||Stellar structure and evolution|
|Published online||23 May 2003|
The protostellar mass limit for 6.7 GHz methanol masers*
I. A low-mass YSO survey
School of Physics, University of New South Wales, Sydney 2052, NSW, Australia
2 Onsala Space Observatory, 439 92 Onsala, Sweden
3 School of Mathematics and Physics, University of Tasmania, Private Bag 21, Hobart 7001, TAS, Australia
4 Australia Telescope National Facility, PO Box 76, Epping 1710, NSW, Australia
Corresponding author: V. Minier, firstname.lastname@example.org
Accepted: 27 March 2003
We report the results of a search for 6.7 GHz methanol masers toward low-mass young stellar objects (YSOs) and (pre)protostellar condensations with the Australia Telescope Compact Array (ATCA). Our sample consisted of 13 class 0 protostars and 44 class I YSOs as well as 66 (pre)protostellar condensations. A single detection was obtained toward NGC 2024: FIR4 in the Orion B region. This is the first detection of a 6.7 GHz methanol maser in Orion. The nature of FIR4 has been a subject of debate with some evidence suggesting that it is a very cold high-mass (pre)protostellar condensation and others arguing that it is a low-mass YSO. The discovery of a methanol maser associated with this source is inconsistent with both of these hypotheses and we suggest that FIR4 probably harbours an intermediate- or high-mass YSO. The less massive objects in our sample do not exhibit any methanol maser stronger than 400 mJy (4σ). Based on the nil detection rate toward the low-mass YSOs we can place an upper limit of K on the brightness temperature of any methanol maser associated with class 0, I or II sources. These results support the hypothesis that no strong methanol masers are associated with low-mass star formation ( ).
Key words: masers / stars: formation / stars: circumstellar matter
© ESO, 2003
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.