We report here the results of a 4‐yr K‐band (2.2 μm) survey for large‐amplitude variable stars in a area centred on the Galactic Centre. A total of 409 likely long‐period variables (LPVs) were detected, for which positions, amplitudes, average magnitudes and periods were obtained whenever possible. The surface density of LPVs is more than ten times greater than in the Sgr I Baade window at The limits of completeness arising from interstellar and circumstellar absorption are discussed. Most of the area suffers interstellar extinction of The shorter‐period LPVs are less luminous than the longer‐period ones and may be slightly under‐represented in the data. Extremely heavy extinction which affects the probability of detecting variables, occurs in less than 25 per cent of the area. Almost all of the LPVs are Miras or OH/IR stars, with periods ranging from 150 d to about 800 d. K‐band counterparts have been found for 59 per cent of the 109 known OH sources in the field. The average period of the variables found is 427 d, while that of the OH/IR stars is 524 d. For comparison, the average period in the Sgr I window, which contains no known OH/IR stars, is 333 d and only two stars are detected with The survey field also contains a number of long‐period, large‐amplitude variables that are not OH emitters.

We present observations of the microlensing event MACHO 98-BLG-35, which reached a peak magniÐcation factor of almost 80. These observations by the Microlensing Planet Search (MPS) and MOA collaborations place strong constraints on the possible planetary system of the lens star and show intriguing evidence for a low-mass planet with a mass fraction 4 ] 10~5 ¹ v ¹ 2 ] 10~4. A giant planet with v \ 10~3 is excluded from 95% of the region between 0.4 and 2.5 from the lens star, where is R E R E the Einstein ring radius of the lens. This exclusion region is more extensive than the generic "" lensing zone,ÏÏ which is 0.6È1.6For smaller mass planets, we can exclude 57% of the "" lensing zone ÏÏ for R E . v \ 10~4 and 14% of the lensing zone for v \ 10~5. The mass fraction v \ 10~5 corresponds to an Earth-mass planet for a lensing star of mass D0.3A number of similar events will provide sta-M _ . tistically signiÐcant constraints on the prevalence of Earth-mass planets. In order to put our limits in more familiar terms, we have compared our results to those expected for a solar system clone, averaging over possible lens system distances and orientations. We Ðnd that such a system is ruled out at the 90% conÐdence level. A copy of the solar system with Jupiter replaced by a second Saturn-mass planet can be ruled out at 70% conÐdence. Our low-mass planetary signal (few Earth masses to Neptune mass) is signiÐcant at the 4.5 p conÐdence level. If this planetary interpretation is correct, the MACHO 98-BLG-35 lens system constitutes the Ðrst detection of a low-mass planet orbiting an ordinary star without gas giant planets.20

We report observations of variability amongst the stars of the `Quintuplet' cluster located about 30 pc in projection from the centre of the Galaxy. Two of the five cocoon star members, which may be protostars or peculiar Wolf‐‐Rayet stars, are seen to vary slowly with moderate amplitude (0.4‐‐0.5 mag). The bright star within the `Pistol' H ii region, suspected of being a luminous blue variable (LBV), has in fact been found to show variability, confirming its tentative classification. A second nearby presumed LBV also varies. One of the apparent Quintuplet members is likely to be a Mira variable along the same line of sight.

Optical photometry and H I synthesis observations of the southern edge-on Sc/Sd galaxy IC 5249 are reported. The rotation curve rises linearly out to a radius of 7 kpc and then appears to Ñatten out at D100 km s~1. The H I mass out to 24.5 kpc is D6 ] 109 or 10% of the total mass out to this M _ , radius. The color, central surface brightness, scale height, and scale length of the disk of IC 5249 are R [ I B 0.4, mag arcsec~2, 600^40 pc, and 11^2 kpc, respectively. Additional light k \ 20.6^0.1 R C to that predicted by an exponential disk is present at distances greater than 3 kpc from the disk. At 5 kpc the surface brightness is mag arcsec~2. The measured distribution of surface brightness is 27È28 R C used to constrain the abundance of low-mass main-sequence stars in the halo of the galaxy. A halo made up entirely of main-sequence stars heavier than 0.13 is excluded. We also Ðnd that less than 20% of M _ the halo can be composed of main-sequence stars heavier than 0.30Further observations are M _ . required to determine the rotation curve of IC 5249 to large radii and to determine precisely the abundance of low-mass main-sequence stars in the halo of the galaxy.