J/AN/319/201 Alpha Per cluster low-mass members. I. (Prosser+, 1998)
Identification of new low-mass members of the alpha Persei open cluster
by ROSAT. I.
Prosser C.F., Randich S
<Astron. Nachrichten 319, 201 (1998)>
=1998AN....319..201P 1998AN....319..201P
ADC_Keywords: Clusters, open ; Photometry ; X-ray sources ; Spectroscopy
Keywords: open clusters and associations: individual (alpha Per = Melotte 20) -
stars: late-type - stars: coronae - stars: activity - X-rays: stars
Abstract:
Following the work of Randich et al. (1996A&A...305..785R 1996A&A...305..785R) involving a
ROSAT raster scan survey of the α Persei open cluster, we
present here the results of a photometric/spectroscopic program
examining the possible optical counterparts to a group of 73 X-ray
sources in the raster survey which were not matched to catalogued
stars. Of the 73 sources investigated, ∼40 have an optical counterpart
with photometry acceptable for cluster membership and ∼20 of these
also have radial velocities consistent with membership. We discuss the
X-ray properties of these potential new members and why they may not
have been identified in earlier membership surveys of this cluster.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 55 73 Raster APX X-ray source list
table2.dat 106 89 Optical counterparts
notes.dat 79 102 Individual notes on finding charts (Appendix A)
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See also:
I/68 : Positions and Proper Motions in alpha Per cluster (Fresneau, 1980)
J/AN/319/315 : Alpha Per cluster low-mass members. II. (Prosser+, 1998)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- APX [1/73] APX number
4- 5 I2 h RAh Right ascension (J2000)
7- 8 I2 min RAm Right ascension (J2000)
10- 13 F4.1 s RAs Right ascension (J2000)
15 A1 --- DE- Declination sign (J2000)
16- 17 I2 deg DEd Declination (J2000)
19- 20 I2 arcmin DEm Declination (J2000)
22- 23 I2 arcsec DEs Declination (J2000)
25- 29 F5.1 --- MLh Hardband Maximum Likelihood value
31- 35 I5 s ExpTime Effective exposure time
37- 42 F6.4 s-1 CountRate Count rate
44- 49 F6.4 s-1 e_CountRate rms uncertainty on CountRate
51 A1 --- l_HR Limit flag on HR
52- 55 F4.1 --- HR Hardness ratio (1)
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Note (1): HR=(H-S)/(H+S), where H and S are the count rates from the hard
(0.4-2keV) and soft (0.1-0.4keV) bands respectively
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- APX [1/73] APX number
4- 10 A7 --- Star Star name (1)
11 A1 --- n_Star [ab] Note detailed in notes.dat (2)
12- 13 I2 h RAh Right ascension (J2000)
15- 16 I2 min RAm Right ascension (J2000)
18- 21 F4.1 s RAs Right ascension (J2000)
23 A1 --- DE- Declination sign (J2000)
24- 25 I2 deg DEd Declination (J2000)
27- 28 I2 arcmin DEm Declination (J2000)
30- 31 I2 arcsec DEs Declination (J2000)
33- 37 F5.2 mag Vmag V magnitude
39- 42 F4.2 mag B-V ? B-V colour index
43 A1 --- u_B-V Uncertainty flag on B-V
45- 48 F4.2 mag V-Ik ? (V-I)K colour index
50 I1 --- o_Vmag ? Number of observation in V band
51 I1 --- o_Bmag ? Number of observation in B band
52 I1 --- o_Imag ? Number of observation in I band
54- 57 F4.2 mag B-V0 ? (B-V)0 colour index
59- 63 F5.2 [solLum] log(LX) ? X-ray luminosity
65- 69 F5.2 [solLum] log(Lbol) ? Bolometric luminosity
71- 75 F5.2 --- log(LX/Lbol) ? X-ray to bolometric luminosity ratio
78- 79 A2 --- HaMemb [YN ?] Hα member flag
81 A1 --- Halpha [YN] Hα emission flag
84- 86 F3.1 0.1nm EWHa ? Hα equivalent width
88- 90 I3 km/s RV1 ? Radial velocity for brighter stars,
based on Hα observations
92- 94 I3 km/s RV2 ? Radial velocity for other stars,
based on echelle observations
97 A1 --- l_vsini Limit flag on vsini
98- 99 I2 km/s vsini ? Rotational velocity for brighter stars,
based on echelle observations
100 A1 --- u_vsini Uncertainty flag on vsini
102-103 A2 --- MemRV [YN ?] Membership from radial velocity
105-106 A2 --- Mem [YN ?] Final membership
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Note (1): APNNN: Cl* Melotte 20 AP NNN in Simbad
APXNN: APX NN in Simbad
APXNNA: APX NNA in Simbad
HE NNNN: Cl Melotte 20 NNNN in Simbad
Note (2): a: galaxy
b: SB1 (see note in appena.dat file)
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [APX]
4 - 5 I2 --- APX APX Number
6 A1 --- m_APX Multiplicity index
8- 80 A73 --- Note Text of the note
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History: Prepared via OCR at CDS.
(End) James Marcout, Patricia Bauer [CDS] 30-Apr-1999