J/AJ/149/34 Spectroscopy and photometry of IM Per (Lacy+, 2015)
Absolute properties of the eclipsing binary star IM Persei.
Lacy C.H.S., Torres G., Fekel F.C., Muterspaugh M.W., Southworth J.
<Astron. J., 149, 34 (2015)>
=2015AJ....149...34L 2015AJ....149...34L
ADC_Keywords: Binaries, eclipsing ; Radial velocities ; Photometry, CCD
Keywords: binaries: eclipsing - binaries: spectroscopic -
stars: fundamental parameters - stars: individual: IM Per
Abstract:
IM Per is a detached A7 eccentric eclipsing binary star. We have
obtained extensive measurements of the light curve (28225 differential
magnitude observations) and radial velocity curve (81 spectroscopic
observations) which allow us to fit orbits and determine the absolute
properties of the components very accurately: masses of
1.7831±0.0094 and 1.7741±0.0097 solar masses, and radii of
2.409±0.018 and 2.366±0.017 solar radii. The orbital period is
2.25422694(15) days and the eccentricity is 0.0473(26). A faint third
component was detected in the analysis of the light curves, and also
directly observed in the spectra. The observed rate of apsidal motion
is consistent with theory (U=151.4±8.4year). We determine a distance
to the system of 566±46pc.
Description:
V-band differential photometry was obtained by using the URSA WebScope
at the University of Arkansas at Fayetteville from 2003 September 20
to 2012 March 1 (11212 usable observations) and the NFO WebScope near
Silver City, NM from 2005 January 18 to 2014 February 17 (17,013
usable observations). Descriptions of the telescopes are given by Lacy
et al. 2014 (cat. J/AJ/147/148) and Grauer et al.
(2008PASP..120..992G 2008PASP..120..992G).
IM Per was observed spectroscopically with three different
instruments. Monitoring began in 2004 January at the
Harvard-Smithsonian Center for Astrophysics (CfA) with an echelle
spectrograph ("Digital Speedometer," DS) mounted on the 1.5m
Tillinghast reflector at the F. L. Whipple Observatory (Mount Hopkins,
AZ). A total of 10 spectra were recorded through 2007 December with an
intensified photon-counting Reticon detector providing 45Å of
coverage centered at 5187Å, and including the MgI b triplet. The
resolving power of this instrument was approximately R=35000, and the
signal-to-noise ratios (S/Ns) of the spectra range from 14 to 39 per
resolution element of 8.5km/s.
An additional 22 spectra were obtained with the bench-mounted
Tillinghast Reflector Echelle Spectrograph (TRES) and its CCD detector
on the same telescope from 2010 January to 2014 February. These
observations cover the entire optical range (3860-9100Å) in 51
orders, at a resolving power of about R=44000. The S/Ns near the MgI b
region range from 32 to 89 per resolution element of 6.8km/s.
From 2011 October through 2014 February we acquired 49 usable spectra
of IM Per with the Tennessee State University 2m Automatic
Spectroscopic Telescope (AST) and a fiber-fed echelle spectrograph at
Fairborn Observatory in southeast Arizona. The detector for these
observations was a Fairchild 486 CCD, having 4096*4096 15 micron
pixels. Although the spectrograms have 48 orders ranging from
3800-8260Å, we have analyzed just the orders that cover the
wavelength region from 4920-7100Å. Because of the faintness and
rapid rotation of IM Per, we used a fiber that produced a spectral
resolution of 0.4Å, corresponding to a resolving power of 15000 at
6000. See Fekel et al. 2013 (cat. J/AJ/145/111) for additional
information about the AST facility. Our spectra have typical S/Ns of
40 at 6000Å.
Objects:
----------------------------------------------------------------
RA (ICRS) DE Designation(s) (Period)
----------------------------------------------------------------
03 11 42.31 +52 12 42.2 V* IM Per = CSV 276 (P=2.25423576)
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 52 102 Times of eclipse for IM Per
table2.dat 55 32 *Heliocentric radial velocities of IM Per from
the CfA spectra
table3.dat 31 49 *Heliocentric radial velocities of IM Per from
the Fairborn observatory
table5.dat 23 11212 *Differential V magnitudes of IM Per from the
URSA WebScope
table6.dat 23 17015 *Differential V Magnitudes of IM Per from the
NFO WebScope
refs.dat 92 26 References
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Note on table2.dat: At the Harvard-Smithsonian Center for Astrophysics (CfA).
Note on table3.dat: Fairborn observatory in southeast Arizona.
Note on table5.dat: URSA WebScope at the University of Arkansas at Fayetteville.
Note on table6.dat: NFO WebScope near Silver City, New Mexico.
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
J/AJ/147/148 : Spectroscopy and photometry of AP And (Lacy+, 2014)
J/AJ/147/1 : Spectroscopy and photometry of HP Aur (Lacy+, 2014)
J/AJ/145/111 : Radial velocities of five spectroscopic binaries (Fekel+, 2013)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Running sequence number
5- 13 F9.4 yr Year [1950.70/2014.06] Year
15- 24 F10.4 d HJD Heliocentric Julian Date (HJD-2400000) (1)
26- 32 F7.5 d e_HJD ? Error estimate on HJD (2)
34- 38 I5 --- E [-9371/893] Epoch
40 I1 --- Type [1/2] Eclipse type (1=primary, 2=secondary minima)
42- 49 F8.5 d O-C [-0.003/0.005] The (O-C) residual
51- 52 I2 --- Ref [1/26] Reference; in refs.dat file
--------------------------------------------------------------------------------
Note (1): Numerous measurements of the times of eclipse of IM Per have been made
in the last 20 years using photoelectric/CCD techniques. Nine additional
determinations were obtained from our own photometric measurements
described below. The current eclipse ephemeris is:
HJDminI=2454665.736068(85)+2.25423576(26)E.
Note (2): Uncertainties for the photoelectric/CCD timings are listed as
published. For those with no published errors we assigned an uncertainty of
0.0019days, and 0.008days for the single General Catalogue of Variable
Stars (GCVS; cat. B/gcvs) measurement (see Section 4). Our analysis
indicates that published internal errors for the photoelectric/CCD timings
are underestimated by factors of 1.9 and 2.2 for the primary and secondary,
respectively.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.4 d HJD Heliocentric Julian Date (HJD-2400000)
12- 18 F7.2 km/s HRVA [-158/91] Primary heliocentric radial velocity
20- 24 F5.2 km/s e_HRVA [1/11] 1σ error in HRVA
26- 32 F7.2 km/s HRVB [-156/95] Secondary heliocentric radial velocity
34- 37 F4.2 km/s e_HRVB [1/7] 1σ error in HRVB
39- 44 F6.4 --- Phase [0/1] Phase (G1)
46- 50 F5.1 km/s HRVC [-47/-14]? Tertiary heliocentric radial velocity
(σ 11km/s for DS and 7km/s for TRES) (1)
52- 55 A4 --- Inst Instrument used at the Harvard-Smithsonian Center
for Astrophysics (CfA) (1)
--------------------------------------------------------------------------------
Note (1): Instrument used at Harvard-Smithsonian for Astrophysics (CfA):
DS = Digital Speedometer (typical uncertainty: 11km/s)
TRES = Tillinghast Reflector Echelle Spectrograph (typical uncertainty: 7km/s)
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.4 d HJD Heliocentric Julian Date (HJD-2400000)
12- 17 F6.1 km/s HRVA [-158/95] Primary heliocentric radial velocity
(typical uncertainty of 2.9km/s)
19- 24 F6.1 km/s HRVB [-155/95] Secondary heliocentric radial
(typical uncertainty of 3.0km/s)
26- 31 F6.4 --- Phase [0/1] Phase (G1)
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Byte-by-byte Description of file: table[56].dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.5 d HJD Heliocentric Julian Date (HJD-2400000)
12- 13 A2 --- --- [00]
15- 23 F9.7 mag DVmag [1.84/2.59] Differential V band magnitude (1)
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Note (1): Two comparison stars near the eclipsing binary were used:
GSC 03323 01163 (mag 9.8) and GSC 03323 01366 (mag 9.9). The sum of the
fluxes of both of the two comparison stars was converted into a comparison
star magnitude called "comps," and the differential magnitude
ΔV=var-comps was formed from these magnitudes.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode Bibliographic code
24- 40 A17 --- Aut Author's name
42- 92 A51 --- Com Comments
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Global notes:
Note (G1): Phases are computed from the ephemeris in the last column of
Table 4: HJDminI=2454665.736068(85)+2.25423576(26)E, with phase 0.0
indicating the deeper eclipse of the marginally more massive star (primary).
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 05-Feb-2015