J/ApJ/848/18 High-res. spectroscopic obs. of 2 Herbig stars (Aarnio+, 2017)
High-cadence, high-resolution spectroscopic observations of Herbig stars
HD 98922 and V1295 Aquila.
Aarnio A.N., Monnier J.D., Harries T.J., Kraus S., Calvet N., Acreman D.,
Che X.
<Astrophys. J., 848, 18-18 (2017)>
=2017ApJ...848...18A 2017ApJ...848...18A (SIMBAD/NED BibCode)
ADC_Keywords: Spectra, optical; Stars, pre-main sequence
Keywords: stars: formation; stars: individual: (HD 98922, V1295 Aql);
stars: pre-main sequence; stars: variables: T Tauri, Herbig Ae/Be
Abstract:
Recent observational work has indicated that mechanisms for accretion
and outflow in Herbig Ae/Be star-disk systems may differ from
magnetospheric accretion (MA) as it is thought to occur in T Tauri
star-disk systems. In this work, we assess the temporal evolution of
spectral lines probing accretion and mass loss in Herbig Ae/Be systems
and test for consistency with the MA paradigm. For two Herbig Ae/Be
stars, HD 98922 (B9e) and V1295 Aql (A2e), we have gathered
multi-epoch (∼years) and high-cadence (∼minutes) high-resolution
optical spectra to probe a wide range of kinematic processes.
Employing a line equivalent width evolution correlation metric
introduced here, we identify species co-evolving (indicative of common
line origin) via novel visualization. We interferometrically constrain
often problematically degenerate parameters, inclination and
inner-disk radius, allowing us to focus on the structure of the wind,
magnetosphere, and inner gaseous disk in radiative transfer models.
Over all timescales sampled, the strongest variability occurs within
the blueshifted absorption components of the Balmer series lines; the
strength of variability increases with the cadence of the
observations. Finally, high-resolution spectra allow us to probe
substructure within the Balmer series' blueshifted absorption
components: we observe static, low-velocity features and time-evolving
features at higher velocities. Overall, we find the observed line
morphologies and variability are inconsistent with a scaled-up T Tauri
MA scenario. We suggest that as magnetic field structure and strength
change dramatically with increasing stellar mass from T Tauri to
Herbig Ae/Be stars, so too may accretion and outflow processes.
Description:
From 2006 to 2013, we conducted an optical spectroscopic observational
campaign of a sample of ∼60 HAeBe stars. Over the course of gathering
data, we observed 13 objects at multiple epochs; 2 of these, V1295 Aql
and HD 98922, were followed-up on in 2013 with high-cadence
time-series observations.
Our optical spectra were taken with MIKE, the Magellan Inamori Kyocera
Echelle (Las Campanas Observatory), a cross-dispersed double echelle
spectrograph. The blue side of MIKE covers a ∼3200-5000Å range, and
the red chip spans ∼4900-10000Å; using the narrowest slit, 0.35",
the resolving powers of the blue and red sides are R∼80000 and
R∼65000, respectively.
Objects:
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RA (ICRS) DE Designation(s) Per
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11 22 31.67 -53 22 11.5 HD 98922 = TYC 8617-657-1 (P=4-8)
20 03 02.51 +05 44 16.7 V1295 Aql = HD 190073 (P=32)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 94 451 *Time series observing log with MIKE (the
Magellan Inamori Kyocera Echelle)
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Note on table1.dat: All data are MIKE spectra, unless otherwise indicated
(i.e. 12 ESO -UVES and -HARPS archival spectra).
Time-series spectra were generally taken in sets of four integrations, with
ThAr lamps taken between sets.
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See also:
J/A+A/599/A85 : Structure of Herbig AeBe disks at mas scale (Lazareff+, 2017)
J/A+A/586/A47 : Accretion process in NGC 2264 (Sousa+, 2016)
J/other/NewA/44.1 : IR photometric study of Herbig Ae/Be stars (Chen+, 2016)
J/ApJ/698/2031 : Polarimetry of HAeBe stars (Rodrigues+, 2009)
J/ApJ/653/657 : Spectroscopic obs. of Herbig Ae/Be stars (Manoj+, 2006)
J/A+A/442/1127 : Library of 2500-10500Å synthetic spectra (Munari+, 2005)
J/ApJ/606/L73 : CO emission of 5 Herbig Ae stars (Blake+, 2004)
J/AJ/126/2971 : UBVRI photometry of 131 Herbig Ae/Be (Vieira+, 2003)
J/A+A/378/116 : Classification & vsini of Vega-type & PMS stars (Mora+, 2001)
J/A+A/361/1143 : Proper motions of PMS stars (Teixeira+ 2000)
J/AJ/118/1043 : Herbig Ae/Be stars catalog (Herbst+, 1999)
J/A+AS/104/315 : Member of Herbig Ae/Be stellar group (The+ 1994)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 "Y/M/D" Obs.date Date of the observation
13- 49 A37 --- Desc Description data
51- 59 A9 --- Name Star name ("HD 98922" or "V1295 Aql")
61- 71 A11 "h:m:s" Obs.time UT time of the observation
73- 84 A12 --- Filter Filter use or wavelength range if spectra
(mainly B, R, or 3044-3916AA, 3732-4999AA,
3780-6911 4726-6835AA, 6650-10250AA)
86- 88 I3 s Exp [15/600] Integration time
90- 94 F5.3 --- Airmass [1/2.6]? Airmass
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 07-Jun-2018