J/AJ/150/190 Spectroscopy and Stromgren photometry of HR 1040 (Corliss+, 2015)
Spectroscopic and photometric variability in the A0 supergiant HR 1040.
Corliss D.J., Morrison N.D., Adelman S.J.
<Astron. J., 150, 190 (2015)>
=2015AJ....150..190C 2015AJ....150..190C (SIMBAD/NED BibCode)
ADC_Keywords: Stars, supergiant ; Spectroscopy ; Photometry, uvby ;
Radial velocities ; Equivalent widths
Keywords: methods: statistical - stars: early-type - stars: statistics -
stars: variables: general
Abstract:
A time-series analysis of spectroscopic and photometric observables of
the A0 Ia supergiant HR 1040 has been performed, including equivalent
widths, radial velocities, and Stromgren photometric indices. The
data, obtained from 1993 through 2007, include 152 spectroscopic
observations from the Ritter Observatory 1m telescope and 269
Stromgren photometric observations from the Four College Automated
Photoelectric Telescope. Typical of late B- and early A-type
supergiants, HR 1040 has a highly variable Hα profile. The star
was found to have an intermittent active phase marked by correlation
between the Hα absorption equivalent width and blue-edge radial
velocity and by photospheric connections observed in correlations to
equivalent width, second moment and radial velocity in
SiIIλλ6347,6371. High-velocity absorption (HVA) events
were observed only during this active phase. HVA events in the wind
were preceded by photospheric activity, including SiII radial velocity
oscillations 19-42 days prior to onset of an HVA event and correlated
increases in SiII Wλ and second moment from 13 to 23 days
before the start of the HVA event. While increases in various line
equivalent widths in the wind prior to HVA events have been reported
in the past in other stars, our finding of precursors in enhanced
radial velocity variations in the wind and at the photosphere is a new
result.
Description:
This study includes 152 spectroscopic observations (see Table9) during
14 seasons from 1993 to 2007 from the 1.06m f/8 Ritchey-Chretien
telescope at the Ritter Observatory on the campus of The University of
Toledo and 269 Stromgren photometric observations (see Table10) during
six seasons (from 1998 to 2001 and from 2003 to 2006) from the 0.75m
Four College Automated Photoelectric Telescope (FCAPT) located in
Washington Camp, AZ.
The Ritter Observatory echelle spectrograph was employed with an
entrance slit width that yielded a spectral resolution element
4.3pixels wide at a resolving power of about 26000. Used in this
research were an echelle order centered on Hα with a range from
6527 to 6594Å and the adjacent one including SiII
λλ6347, 6371, with a range from 6340 to 6406Å. The
range of the orders is restricted by the size of the CCD, which is
much smaller than the image plane of the spectrograph. More details
about the instrumentation are given on the Ritter Observatory web site
(http://astro1.panet.utoledo.edu/~wwritter/telescope.html#echelleold).
Objects:
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RA (ICRS) DE Designation(s)
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03 29 54.74 +58 52 43.5 HR 1040 = HD 21389
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table9.dat 124 152 Spectroscopic results and observation log
table10.dat 34 277 Differential Stromgren magnitudes
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See also:
J/AJ/141/17 : 5-year spectroscopy and photometry of Deneb (Richardson+, 2011)
Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 10 F10.2 d HJD Heliocentric Julian date at mid-exposure
12- 16 F5.3 0.1nm EWabs [0.088/1.34] Hα absorption equivalent
width (in Å) (1)
18- 23 F6.4 0.1nm EWLem [0.008/0.16] Hα left (blue) emission
equivalent width (in Å) (1)
25- 30 F6.4 0.1nm EWRem [0.007/0.17] Hα right (red) emission
equivalent width (in Å) (1)
32- 37 F6.2 km/s HRVb [12.5/201] Hα blue edge radial velocity
vBE absolute value (all values are
negative) (2)
39- 44 F6.2 km/s HRVr [-15/88.6] Hα red edge radial velocity
vRE (2)
46- 51 F6.4 0.1nm EW6578 [0.025/0.11] C II λ6578 equivalent
width (in Å) (1)
53- 58 F6.4 0.1nm EW6583 [0.015/0.07] C II λ6583 equivalent
width (in Å) (1)
60- 65 F6.4 0.1nm EW6546 [0.04/0.2] Mg II λ6546 equivalent width
(in Å) (1)
67- 71 F5.3 0.1nm EW6347 [0/2.7] Si II λ6347 equivalent width
(in Å) (1)
73- 77 F5.3 0.1nm EW6371 [0/3.55] Si II λ6371 equivalent width
(in Å) (1)
79- 83 F5.2 km/s HRV6347 [-9.2/14.9] Si II λ6347 radial
velocity (3)
85- 90 F6.3 km/s HRV6371 [-8.6/13] Si II λ6371 radial
velocity (3)
92- 96 F5.3 0.1nm2 M26347 [0.022/2.72] Si II λ6347 second moment
(in Å2) (4)
98-101 I4 s Exp [900/3600] Exposure time
103-105 I3 --- S/N [20/161] Signal-to-noise ratio per pixel
107-124 A18 --- Obs Initals of observer(s) (5)
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Note (1): Equivalent widths were calculated relative to the local continuum,
using integration limits given in Table3 (see the paper) and illustrated
for the Hα emission components and nearby lines in Figure2.
See Section 2.2.1 for more details.
Note (2): The blue- and red-edge velocities of Hα were defined in terms of
a one-piece quartic spline through points in the blue and red wings of the
line profile (Figure 3). See Section 2.2.2 for additional details.
Note (3): In this material, only SiII λλ6347,6371 are deep and
sharp (mean full width at half depth 1.4Å) enough to support an accurate
measurement of radial velocity. See Section 2.2.2 for further details.
Note (4): The second moment of a distribution, M2, is a measure of its width,
being defined by the integral:
∫(x-µ)2f(x)dx (Eq. (1) in the paper).
Note (5): The Ritter observers who collected the data are listed as follows:
JA = Jason Aufdenberg;
KSB = Karen Bjorkman;
WJF = Will Fischer;
KG = Karl Gordon;
ENH = Erica Hesselbach;
DWK = Dan Kittell;
DCK = David Knauth;
NMK = Nicole Kurschat;
DRL = Douglas Long;
IJM = Ian McGinness;
AM = Anatoly Miroshnichenko;
NDM = Nancy Morrison;
CLM = Christopher Mulliss;
JKP = Jens Petersohn;
AMR = Adam Ritchey;
HLR = Howard Ritter;
SJR = Sara Rother;
TLS = Tracy Smith;
NNS = Nicholas Sperling;
JT = Joshua Thomas;
GBT = Greg Thompson;
JPW = John Wisniewski
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Byte-by-byte Description of file: table10.dat
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Bytes Format Units Label Explanations
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1- 10 F10.2 d HJD Heliocentric Julian Date
12- 16 F5.3 mag umag [0.4/0.9] Differential Stromgren u band magnitude
18- 22 F5.3 mag vmag [0.6/1.1] Differential Stromgren v band magnitude
24- 28 F5.3 mag bmag [0.4/0.7] Differential Stromgren b band magnitude
30- 34 F5.3 mag ymag [0.09/0.3] Differential Stromgren y band magnitude
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 26-Apr-2016