J/ApJ/789/L38 LRLL54361 protostar Herschel/PACS fluxes (Balog+, 2014)
The extraordinary far-infrared variation of a protostar: Herschel/PACS
observations of LRLL54361.
Balog Z., Muzerolle J., Flaherty K., Detre O.H., Bouwmann J., Furlan E.,
Gutermuth R., Juhasz A., Bally J., Nielbock M., Klaas U., Krause O.,
Henning T., Marton G.
<Astrophys. J., 789, L38 (2014)>
=2014ApJ...789L..38B 2014ApJ...789L..38B (SIMBAD/NED BibCode)
ADC_Keywords: Photometry, infrared ; Protostars
Keywords: infrared: stars - stars: formation - stars: individual: LRLL54361 -
stars: protostars - stars: variables: general
Abstract:
We report Herschel/Photodetector Array Camera and Spectrometer (PACS)
photometric observations at 70 µm and 160 µm of LRLL54361, a
suspected binary protostar that exhibits periodic (P = 25.34 days)
flux variations at shorter wavelengths (3.6 µm and 4.5 µm)
thought to be due to pulsed accretion caused by binary motion. The
PACS observations show unprecedented flux variation at these
far-infrared wavelengths that are well correlated with the variations
at shorter wavelengths. At 70 µm the object increases its flux by a
factor of six while at 160 µm the change is about a factor of two,
consistent with the wavelength dependence seen in the far-infrared
spectra. The source is marginally resolved at 70 µm with varying
FWHM. Deconvolved images of the sources show elongations exactly
matching the outflow cavities traced by the scattered light
observations. The spatial variations are anti-correlated with the flux
variation, indicating that a light echo is responsible for the changes
in FWHM. The observed far-infrared flux variability indicates that the
disk and envelope of this source is periodically heated by the
accretion pulses of the central source, and suggests that such long
wavelength variability in general may provide a reasonable proxy for
accretion variations in protostars.
Description:
We observed a 14'x14' area in IC348 with the Photodetector Array
Camera and Spectrometer (PACS; Poglitsch et al. 2010A&A...518L...2P 2010A&A...518L...2P)
Herschel Space Observatory (Pilbratt et al. 2010A&A...518L...1P 2010A&A...518L...1P)
simultaneously at 70 and 160um 24 times in scan map mode. An
additional five epoch were observed during a later pulse phase of
LRLL54361 in all three PACS photometer bands. The PACS spectrograph
consists of a 5x5 array of 9.4" x 9.4" spatial pixels
(hereafter referred to as spaxels) covering the spectral range from
52-210 um with λ/δλ ∼1000-3000. Spectra were obtained
in two spectral orders simultaneously, with the second order ranging
from 51 to 105um and the first order from 102 to 210um. The
spatial resolution of PACS-S ranges from ∼9'' at 50um to ∼18'' at
210um. Our target was observed in the standard range-scan
spectroscopy mode with a grating step size corresponding to Nyquist
sampling (see further Poglitsch et al. 2010A&A...518L...2P 2010A&A...518L...2P).
Objects:
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RA (ICRS) DE Designation(s)
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03 43 51.02 +32 03 08.1 LRLL54361 = Cl* IC 348 LRL 54361
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 80 33 Observing log of the observations and measured
fluxes
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See also:
J/A+A/419/999 : Infrared knots along protostellar jets (Giannini+, 2004)
J/AJ/144/31 : Spitzer+2MASS photometry of protostar candidates
(Kryukova+, 2012)
J/AJ/145/94 : Luminosities of protostars from two Spitzer surveys
(Dunham+, 2013)
J/AJ/151/75 : Herschel-PACS and -SPIRE spectroscopy of 70 objects
(Green+, 2016)
J/ApJS/224/5 : The Herschel Orion Protostar Survey (HOPS): SEDs (Furlan+, 2016
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 I1 --- Cycle ? Cycle number (1)
3- 6 I4 yr Obs.Y Year of the observation
8- 9 I2 "month" Obs.M Month of the observation
11- 12 I2 d Obs.D Day of the observation
14- 15 I2 h Obs.h Hour of the observation
17- 18 I2 min Obs.m Minute of the observation
20- 23 F4.1 s Obs.s Second of the observation
25- 35 F11.3 d JD Julian Date of the observation
37- 41 F5.3 --- Phase Phase (2)
43- 48 F6.3 Jy F70 ? Herschel/PACS 70 micron band flux density
50- 54 F5.3 Jy e_F70 ? Error in F70
56- 61 F6.3 Jy F100 ? Herschel/PACS 100 micron band flux density
63- 67 F5.3 Jy e_F100 ? Error in F100
69- 74 F6.3 Jy F160 ? Herschel/PACS 160 micron band flux density
76- 80 F5.3 Jy e_F160 ? Error in F160
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Note (1): The last four lines without Cycle values give the spectrocopy
information. The first 29 lines with Cycle values are the photometry.
Note (2): We calculated the phase of the observations based on the period of
25.34 days and zero point JD 2455121.203 reported by
Muzerolle et al. (2013, J/other/Nat/493.378). Phase=0 corresponds to
the peak flux, as measured from the Spitzer/IRAC observations.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 08-Mar-2017