X Ophiuchi
Program Star (variable)
X OphiuchiSpectral Type:
KIIII+M6IIIeSAO123744
HR7002
HD172171RA (2000) 18h 38m 20.97s
Dec(2000) 08d 50' 02"J~ 0.10
H~ -0.70
V~ 5.9 max
delta V= 3.3
(R-I)~ ?
B~ 7.72
(B-V)~ +1.32
U~ 8.11
(U-B)~ +0.89Period= 334.2 d
Comparison Star
60 beta Ophiuchi
Spectral Type:
K2III
SAO122671
HR6603
HD161096
RA(2000) 17h
43m 28.357s
Dec (2000) +04d 34' 2.20"
J= +0.90
H= +0.40
V= 2.77
(R-I)= +0.57
B= 3.93
(B-V)= +1.16
U=5.17
(U-B)= +1.24
Check Star
58 eta Serpentis
Spectral Type:
K2IIIabCN1
SAO142241
HR6869
HD168723
RA(2000) 18h 21m 18.595s
Dec (2000) -02d 53' 55.8"
J=1.60
H= 1.11
V= 3.26
(R-I) = +0.50
B= 4.20
(B-V)= +0.94
U= 4.86
(U-B)= +0.66
Possible Variable
Principal Investigator: ???????????????????? e-mail: ?????????
Objective: To determine period of the star system.
Season: Early morning in January through fall.
There may be some confusion between chi (the Greek letter similar to X) and X Ophiuchi.
X Ophiuchi is a Mira variable and it is well observed by visual AAVSO observers. It is rather unique because it is a known binary system. The separation is less than one arc second. The binary system has been measured for over a century and the orbit has been calculated. This helps us determine the mass of stars. Compared to visual or V band observations, J and H band observations are relatively rare. The light curve for X Oph has never been measured in J and H (at least it has been published). The light curves helps astronomers determine the physical processes occurring within the star.
Title: The Binary System X Ophiuchi.
Authors: Fernie, J. D. Publication: Astrophysical Journal, vol. 130, p.611 (ApJ Homepage) Publication Date: 09/1959
Origin: ADS Bibliographic Code: 1959ApJ...130..611FAbstract
A study of all available observations of the X Oph visual binary system (K1 III t M6e) is described. It is concluded that the mass of the long-period variable component is close to , compared to the mass of about predicted by the mass-luminosity relation. This smaller mass leads to a pulsation constant, P Vp similar to that observed for other types of variables and in close agreement with theory. The age of X Oph is about 5^10 years, and hence probably all long-period variables are old. Evidence is given to support the suggestion that long-period variables evolve from early F dwarfs. It is shown that the binary nature of X Oph has not in any way affected its evolution and that it is not necessary, therefore, for a star to belong to a binary system in order to become a long-period variable.
Data Summary
|
Date
|
JD
|
J
|
#
|
Err
|
H
|
#
|
Err
|
X
|
Obs
|
Notes
|
|
MAR 10.4500
|
2453074.95
|
0.48
|
?
|
?
|
-0.24
|
?
|
?
|
?
|
WJD
|
|
|
MAR 30.4722
|
2453094.9722
|
0.45
|
?
|
?
|
-0.26
|
?
|
?
|
?
|
WJD
|
|
|
APR 14.3993
|
2453109.8993
|
?
|
?
|
?
|
-0.36
|
?
|
?
|
?
|
WJD
|
Note 2
|
|
453123.9236
|
0.25
|
?
|
?
|
-0.50
|
?
|
?
|
?
|
WJD
|
||
|
MAY 04.4257
|
2453129.9257
|
0.19
|
?
|
?
|
-.56
|
?
|
?
|
?
|
WJD
|
|
|
2006
|
||||||||||
|
JAN 14.5347
|
2453750.0347
|
0.42
|
2
|
0.01
|
-0.38
|
2
|
0.01
|
?
|
WJD
|
7,12,19
|
|
MAR 27.4653
|
2453821.9653
|
0.17
|
2
|
0.02
|
-0.63
|
2
|
0.02
|
?
|
WJD
|
7,12,19
|
|
MAR 31.4674
|
2453825.9674
|
0.18
|
2
|
0.01
|
-0.65
|
2
|
0.01
|
?
|
WJD
|
7,12,19
|
|
APR 04.4222
|
2453829.9222
|
0.17
|
2
|
0.01
|
-0.65
|
2
|
0.01
|
?
|
WJD
|
7,12,19
|
|
APR 09.4840
|
2453834.9840
|
0.16
|
1
|
0.05
|
-0.69
|
1
|
0.05
|
?
|
WJD
|
12,13,15
|
|
APR 13.4271
|
2453838.9271
|
0.10
|
2
|
0.06
|
-0.68
|
2
|
0.01
|
?
|
WJD
|
7,12,19
|
|
APR 17.4285
|
2453842.9285
|
0.11
|
2
|
0.01
|
-0.70
|
2
|
0.01
|
?
|
WJD
|
7,12,19
|
|
APR 27.4285
|
2453852.9285
|
0.06
|
2
|
0.02
|
-0.74
|
2
|
0.01
|
?
|
WJD
|
7,12,19
|
|
MAY 03.4271
|
2453858.9271
|
0.03
|
2
|
0.01
|
-0.76
|
2
|
0.01
|
?
|
WJD
|
7,12,19
|
|
MAY 23.4208
|
2453878.9208
|
-0.02
|
2
|
0.04
|
-.079
|
2
|
0.05
|
?
|
WJD
|
7,12,19
|
|
MAY 25.4264
|
2453880.9264
|
-0.01
|
2
|
0.02
|
-0.82
|
2
|
0.01
|
?
|
WJD
|
7,12,19
|
|
JUN 02.4264
|
2453888.9264
|
0.02
|
2
|
0.02
|
-.82
|
2
|
0.01
|
?
|
WJD
|
7,12,19
|
|
JUL 24.1125
|
2453940.6125
|
0.07
|
2
|
0.02
|
-.76
|
2
|
0.02
|
?
|
WJD
|
7,12,19
|
|
JUL 26.1076
|
2453942.6076
|
0.08
|
2
|
0.08
|
-.76
|
2
|
0.04
|
?
|
WJD
|
7,12,19
|
|
JUL 30.1028
|
2453946.6028
|
0.13
|
2
|
0.09
|
-.78
|
2
|
0.02
|
?
|
WJD
|
7,12,19
|
|
AUG 21.0931
|
2453968.5931
|
0.18
|
2
|
0.02
|
-.68
|
2
|
0.01
|
?
|
WJD
|
7,12,19
|
|
AUG 30.0799
|
2453977.5799
|
0.25
|
2
|
0.00
|
-0.61
|
2
|
0.00
|
?
|
WJD
|
7,12,19
|
|
OCT 13.1056
|
2454021.6056
|
0.38
|
2
|
0.01
|
-0.42
|
2
|
0.02
|
?
|
WJD
|
7,12,19
|
Comparison Star: SAO 122671 (J=0.90, H=0.40)
Check Star: SAO 142241 (J=1.60, H=1.11).
Observers:
WJD = Doug West, 0.25m SCT, Mulvane, KSNotes:
2. The J band observations had too large difference in comparison stars to be used. Passing cloud?
7. Err term is the standard deviation of measurements.
12. Not corrected for color or airmass differences.
13. Observation procedure: CVK
15. Err is an estimate based on previous observations.
19. Observation procedure: CVCVK.
Phase Plot
15 October 2006 by Doug West
Created 22 October 2006
Modified 22 October 2006
