2018A&A...612A.103C


Query : 2018A&A...612A.103C

2018A&A...612A.103C - Astronomy and Astrophysics, volume 612A, 103-103 (2018/4-1)

Radio outburst from a massive (proto)star. When accretion turns into ejection.

CESARONI R., MOSCADELLI L., NERI R., SANNA A., CARATTI O GARATTI A., EISLOFFEL J., STECKLUM B., RAY T. and WALMSLEY C.M.

Abstract (from CDS):


Context. Recent observations of the massive young stellar object S255 NIRS 3 have revealed a large increase in both methanol maser flux density and IR emission, which have been interpreted as the result of an accretion outburst, possibly due to instabilities in a circumstellar disk. This indicates that this type of accretion event could be common in young/forming early-type stars and in their lower mass siblings, and supports the idea that accretion onto the star may occur in a non-continuous way.
Aims. As accretion and ejection are believed to be tightly associated phenomena, we wanted to confirm the accretion interpretation of the outburst in S255 NIRS 3 by detecting the corresponding burst of the associated thermal jet.
Methods. We monitored the radio continuum emission from S255 NIRS 3 at four bands using the Karl G. Jansky Very Large Array. The millimetre continuum emission was also observed with both the Northern Extended Millimeter Array of IRAM and the Atacama Large Millimeter/Submillimeter Array.
Results. We have detected an exponential increase in the radio flux density from 6 to 45GHz starting right after July 10, 2016, namely ∼13 months after the estimated onset of the IR outburst. This is the first ever detection of a radio burst associated with an IR accretion outburst from a young stellar object. The flux density at all observed centimetre bands can be reproduced with a simple expanding jet model. At millimetre wavelengths we infer a marginal flux increase with respect to the literature values and we show this is due to free-free emission from the radio jet.
Conclusions. Our model fits indicate a significant increase in the jet opening angle and ionized mass loss rate with time. For the first time, we can estimate the ionization fraction in the jet and conclude that this must be low (<14%), lending strong support to the idea that the neutral component is dominant in thermal jets. Our findings strongly suggest that recurrent accretion + ejection episodes may be the main route to the formation of massive stars.

Abstract Copyright: © ESO 2018

Journal keyword(s): stars: early-type - stars: formation - stars: winds, outflows - ISM: jets and outflows

Simbad objects: 10

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Number of rows : 10
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 3C 48 QSO 01 37 41.2996631208 +33 09 35.080388820   16.62 16.20     ~ 2680 2
2 EM* LkHA 101 Em* 04 30 14.4355820328 +35 16 23.983198932   17.91 15.71 13.33   F 324 1
3 QSO B0507+179 QSO 05 10 02.3689932504 +18 00 41.582562768   20.0 19.0 19.09   ~ 373 1
4 NVSS J055932+235354 Rad 05 59 32.03313165 +23 53 53.9267683           ~ 45 1
5 [WBB2011] S255IR-SMA2 mm 06 12 53.77 +17 59 26.1           ~ 10 0
6 MMB G192.600-00.048 Y*O 06 12 54.0100 +17 59 23.200           ~ 367 0
7 QSO J0613+1306 QSO 06 13 57.6930897120 +13 06 45.406606500       19.5   ~ 52 1
8 QSO B0748+126 QSO 07 50 52.0455280992 +12 31 04.828034820   17.67 17.28 17.16   ~ 302 1
9 V* V723 Car Or* 10 43 23.26 -59 33 56.7           ~ 15 0
10 [BHC2016] MM1 mm 17 20 53.415 -35 46 57.88           ~ 66 0

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2022.06.29-20:45:09

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