Difference between revisions of "Triggers:FUOri"

From Gaia Science Alerts Working Group
Jump to: navigation, search
 
(6 intermediate revisions by 3 users not shown)
Line 1: Line 1:
== FU Orionis (FUors) ==
+
== Eruptive YSOs ==
FU Orionis (V1647 Ori) is young pre-main sequence stars, illuminating a McNeil's nebula in the vicinity of NGC 2068 star-forming region.
+
 
 +
Prototypes:
 +
 
 +
FU Oris are an extreme subsample of eruptive classical T Tauri stars. Only one outburst observed, but lasts for decades. Only about a dozen FU Ori bursts observed. V1647 Ori is illuminating a McNeil's nebula in the vicinity of NGC 2068 star-forming region.
  
 
[[File:FUOri.png]]
 
[[File:FUOri.png]]
 
Plot from [http://www.ta3.sk/caosp/Eedition/FullTexts/vol36no3/pp149-157.pdf D.Chochol et al. 2006].
 
Plot from [http://www.ta3.sk/caosp/Eedition/FullTexts/vol36no3/pp149-157.pdf D.Chochol et al. 2006].
 +
 +
EX Lupis (EXors) have smaller, shorter, recurrent outbursts.
 +
 +
[[File:ExLupi.png|right|400px|thumb|EX Lupi photometry from the ASAS project.]]
 +
 +
OO Ser was discovered in 1994 and is similar to FUors and EXors, but is so deeply embedded, that at its brightest was not visible in J band ([http://ukads.nottingham.ac.uk/abs/1996ApJ...468..861H Hodapp et al. 1996]).
 +
It was observed in infrared with ''Infrared Space Observatory'' and Spitzer ([http://arxiv.org/abs/0705.1231 Kospal et al. 2007]).
 +
It has different time scales than FUors and EXors, is rather a ''fast'' FUor (similar to V1647 Ori) with a time of rise of about 8 months.
  
 
Characteristics:
 
Characteristics:
  
* Very rare
+
* diverse zoo of lightcurves, use of templates is risky
* Outbursts repeat with a time scale of 40 years (1978, 2003)
+
* many details unknown, unbiased sample required
* Amplitude: 5 mag over 4 months
+
* rise time varies from months to years  
* Outbursts last for 2 years
+
* amplitude range from <1 mag to 5 mag (but 1mag cutoff is probably useful)
* Spectra: F or G supergiants
+
* outburst last from months to decades, some are recurrent
* Spectrum: red, heavily veiled continuum with strong emission of <math>H_{\alpha}</math>; in blue consistent with an early B spectral type
+
* extreme events like FU Ori are very rare
 +
* Spectra: F or G supergiants, red, heavily veiled continuum with strong emission of <math>H_{\alpha}</math>
 +
* At maximum spectral types are in the range Ae(alpha) - Gpe(alpha)
 
* X-ray variability present
 
* X-ray variability present
 
* FU Ori and V1057 Cyg rise over 1 yr, whereas V1515 Cyg rise over 20 years
 
* FU Ori and V1057 Cyg rise over 1 yr, whereas V1515 Cyg rise over 20 years
 
* FU Ori and V1515 Cyg decline over 20-100 years, V1015 Cyg decays faster (10 yrs)
 
* FU Ori and V1515 Cyg decline over 20-100 years, V1015 Cyg decays faster (10 yrs)
  
== Similar types to FU Ori ==
+
Trigger is necessary, because immediate follow-up (on timescales of weeks) needed to study the impact of
=== EX Lupis (EXors) ===
+
such accretion bursts on the properties of the dust and gas in the disks. Also, high cadence monitoring
 
+
immediately after the event is useful for modeling the source.
[[File:ExLupi.png|right|400px|thumb|EX Lupi photometry from the ASAS project.]]
 
  
See Herbig (2007) [http://www.iop.org/EJ/article/1538-3881/133/6/2679/205809.text.html]
+
Identification:
 +
* >1mag rise in magnitude
 +
* red spectrum, any spectral type
 +
* J-K>1. IR excess, UV excess
 +
* IRAC3 [5.8mu] - IRAC4 [8.0mu] > 0.4
 +
* WISE1 [3.5mu] - WISE4 [22mu] > 2.0
 +
* WISE1 [3.5mu] - WISE2 [4.5mu] > 0.3 (weak criterion)
 +
* Halpha emission
  
* Recurent eruptions
+
References:
* Amplitudes similar or smaller than in FUors
 
* Balmer emission lines, He I and other lines as in active T Tauri stars
 
  
=== OO Serpentis ===
+
* Hartmann & Kenyon 1996 review: http://adsabs.harvard.edu/abs/1996ARA%26A..34..207H
OO Ser was discovered in 1994 and is similar to FUors and EXors, but is so deeply embedded, that at its brightest was not visible in J band ([http://ukads.nottingham.ac.uk/abs/1996ApJ...468..861H Hodapp et al. 1996]).
+
* Scholz et al. 2013 systematic survey: http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1301.3152
It was observed in infrared with ''Infrared Space Observatory'' and Spitzer ([http://arxiv.org/abs/0705.1231 Kospal et al. 2007]).
+
* Clarke et al. 2005 with example lightcurves (Fig. 1): http://adsabs.harvard.edu/abs/2005MNRAS.361..942C
It has different time scales than FUors and EXors, is rather a ''fast'' FUor (similar to V1647 Ori) with a time of rise of about 8 months.
 

Latest revision as of 16:09, 24 July 2013

Eruptive YSOs

Prototypes:

FU Oris are an extreme subsample of eruptive classical T Tauri stars. Only one outburst observed, but lasts for decades. Only about a dozen FU Ori bursts observed. V1647 Ori is illuminating a McNeil's nebula in the vicinity of NGC 2068 star-forming region.

FUOri.png Plot from D.Chochol et al. 2006.

EX Lupis (EXors) have smaller, shorter, recurrent outbursts.

EX Lupi photometry from the ASAS project.

OO Ser was discovered in 1994 and is similar to FUors and EXors, but is so deeply embedded, that at its brightest was not visible in J band (Hodapp et al. 1996). It was observed in infrared with Infrared Space Observatory and Spitzer (Kospal et al. 2007). It has different time scales than FUors and EXors, is rather a fast FUor (similar to V1647 Ori) with a time of rise of about 8 months.

Characteristics:

  • diverse zoo of lightcurves, use of templates is risky
  • many details unknown, unbiased sample required
  • rise time varies from months to years
  • amplitude range from <1 mag to 5 mag (but 1mag cutoff is probably useful)
  • outburst last from months to decades, some are recurrent
  • extreme events like FU Ori are very rare
  • Spectra: F or G supergiants, red, heavily veiled continuum with strong emission of <math>H_{\alpha}</math>
  • At maximum spectral types are in the range Ae(alpha) - Gpe(alpha)
  • X-ray variability present
  • FU Ori and V1057 Cyg rise over 1 yr, whereas V1515 Cyg rise over 20 years
  • FU Ori and V1515 Cyg decline over 20-100 years, V1015 Cyg decays faster (10 yrs)

Trigger is necessary, because immediate follow-up (on timescales of weeks) needed to study the impact of such accretion bursts on the properties of the dust and gas in the disks. Also, high cadence monitoring immediately after the event is useful for modeling the source.

Identification:

  • >1mag rise in magnitude
  • red spectrum, any spectral type
  • J-K>1. IR excess, UV excess
  • IRAC3 [5.8mu] - IRAC4 [8.0mu] > 0.4
  • WISE1 [3.5mu] - WISE4 [22mu] > 2.0
  • WISE1 [3.5mu] - WISE2 [4.5mu] > 0.3 (weak criterion)
  • Halpha emission

References: