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2.5. The optical/IR star: LS 5039 57
Table 2.4: Optical photometry of LS 5039.
Date Julian Day V R I
[JD−2400000]
1998 Jun 2 50966.5 11.35 — —
1998 Jun 3 50967.6 11.33 — —
1998 Jun 7 50971.6 11.35 10.64 9.90
1998 Jun 8 50972.5 11.39 10.69 9.95
Compilation of optical and near infrared observations
Optical and/or near infrared photometry of LS 5039 has been published in the past
by Drilling (1975, 1991), Lahulla & Hilton (1992), Kilkenny et al. (1993), Spencer
Jones et al. (1993), Martí et al. (1998, see Table 2.4) and Clark et al. (2001).
We have compiled all simultaneous broad band (at least 3 filters) measurements in
Table 2.5, where the initials and numbers refer to the cited papers. As can be seen,
all values are consistent with a long-term variability smaller than ∼ 0.1 mag in all
filters except in V , where it varies ∼ 0.2 mag. This suggests that no strong optical
variations appear to be present on timescales of years.
Nevertheless, Clark et al. (2001) also report broad band JHK photometry in the
period 1995–2000 that indicates variability up to ∼0.4 mag in H band and ∼0.5 mag
in K band. These authors also searched for medium-term variability in the B and V
bands during 21 nights spanning 43 days. They only could find aperiodic variability
at the hundredth of magnitude level, on single nights and from night to night, that
can be attributed to variations in mass loss rate or to non-radial pulsations.
Table 2.5: Compilation of optical and near infrared photometry of LS 5039.
Observation U B V R I J H K L
D91 12.02 ± 0.02 12.18 ± 0.01 11.23 ± 0.01 — — — — — —
LH92 11.97 ± 0.02 12.15 ± 0.02 11.20 ± 0.02 — — — — — —
K93, SJ93 — — 11.24 ± 0.01 10.59 ± 0.01 9.88 ± 0.01 9.02 ± 0.01 8.79 ± 0.02 8.57 ± 0.03
1996 Oct, C01 — 12.18 ± 0.02 11.33 ± 0.02 10.65 ± 0.02 9.87 ± 0.02 9.05 ± 0.02 8.75 ± 0.02 8.60 ± 0.02 8.69 ± 0.05
1998 Jun 7 M98 — — 11.35 ± 0.03 10.64 ± 0.03 9.90 ± 0.03 — — — —
1998 Jun 8, M98 — — 11.39 ± 0.03 10.69 ± 0.03 9.95 ± 0.03 — — — —
2000 Sep, C01 — 12.17 ± 0.03 11.32 ± 0.01 10.61 ± 0.01 9.91 ± 0.01 — — — —