CF Cir
ILLUSTRATION FROM MEASURED TEMPERATURE · 23 800 K · 0.553 L☉ · VARIABLE, MAG 11.77–12.28 · TIMING NOT TO SCALE
OVERVIEW
] STARCF Cir is a WN5-w Wolf-Rayet star in the constellation Circinus, 673.9 from Earth, shining at apparent magnitude 12.07 (). Other catalogues list it as HIP 69445.
- WHAT IT IS
- Wolf-Rayet star
- HOW FAR
- 673.9
- HOW BRIGHT (V)
The light arriving now left it that long ago.
A small telescope reaches it.
THE MODEL
] CATALOGUED RADIUSCALCULATED · NOT AN OBSERVATION · CATALOGUED RADIUS · MEASURED TEMPERATURE · 23 800 K · 0.553 L☉ · VARIABLE, MAG 11.77–12.28 · RADIATIVE ENVELOPE · NO SPOTS, FLARES OR CORONA
Drawn from the catalogued radius and from the same properties the picture at the top of this page uses, at the distance a flight to it would stop. The disc is darker and redder at its edge because a ray leaving at a slant escapes from a shallower, cooler layer of the atmosphere, and the mottling on it is convection. There is nothing else on it: a star this hot carries its energy out through the envelope by radiation rather than convection, and with no convection at the surface there is no dynamo, so no spots, no flares and no corona — which is also why stars above about six and a half thousand kelvin still spin as fast as they were born spinning. Drag it, or use the arrow keys, to look from another direction. The stars behind are the 498,631 this catalogue holds real distances for, drawn from where the camera actually is — but every one of them is within 170 parsecs of the Sun and this object is much further out, so from here that whole neighbourhood is a knot in one direction and the rest of the sky is empty. The view you land on looks the other way; turn back towards the Sun and the stars come with it. What the readout says is which of the two the frame is pointed at. The emptiness is not a missing backdrop — it is the edge of what this catalogue has measured.
OBSERVING
] FROM WHERE YOU AREWhat it takes to see CF Cir for yourself. Everything in this part of the page is worked out for a real horizon, a real night and the equipment you say you have.
Say where you are, and this line says when CF Cir is worth going out for.
THROUGH AN EYEPIECE
] 150 MM TELESCOPE · 25 MM EYEPIECEOut of reach of binoculars; a 150 mm telescope reaches it. It will be a point of light in anything: a star is far enough away that no aperture on Earth gives it a width, and all the equipment changes is how easily you find it.
- 48×
- 1.08
- 1.25
- 13.0
- APPARENT MAGNITUDE ()
- 12.07 · within reach
APPARENT PLACE
] EQUINOX J2026.8Where a telescope has to be pointed today, which is not quite where the catalogue records the object: the coordinate grid itself has turned since the year 2000 the catalogue is referred to.
- RIGHT ASCENSION
- DECLINATION
- GRID TURNED SINCE
- 15.1
- PROPER MOTION SINCE
- 0.12
Computed for 2026-10-14 00:00 UT. Two things separate it from the catalogued position above: CF Cir has moved under its own proper motion, and the coordinate grid has turned under it — about fifty arcseconds a year of precession since 2000, and the small nodding of the Earth’s axis on top of that. The catalogue it came from publishes no error for that position, so nothing here says how far this arithmetic can be trusted — the digits above are as precise as the place they were computed from, and no more. Aberration, parallax and refraction are left out. Aberration swings every position by up to twenty arcseconds over a year; parallax stays under an arcsecond for all but the nearest stars; refraction is nothing overhead and about half a degree at the horizon, where it answers to the air, not the sky. The same figure for any date.
VARIABILITY
] WOLF-RAYET STAR WITH VARIABLE EMISSION- RANGE, AS SAMPLED
- 11.77 – 12.28
No period is published for this star, so there is no cycle to count. The catalogue records that it varies and by how much, and not how often.
The range is the spread the Hipparcos satellite measured, converted to the visual scale. It is approximate: the satellite sampled the star on a schedule of its own, and where a star spends little of its cycle at an extreme — the floor of an eclipse, most obviously — the sampling can miss it altogether. The classification is the General Catalogue of Variable Stars’s. These elements as data.
LIFE OF THIS STAR
] STAGE 3 OF 5CF Cir is a Wolf-Rayet star — a heavy star whose own wind has stripped its outer layers away, leaving the fusing interior bare; within about three hundred thousand years it will collapse and explode as a supernova, leaving a black hole.
- COLLAPSING CLOUDtook about twenty thousand years
- MAIN SEQUENCElasted about three million years
- SUPERGIANTabout three hundred thousand years of itNOW
- SUPERNOVAbright for weeks, over in a second
- BLACK HOLEfor the rest of time
NOW The same swelling, on a star heavy enough to keep going: helium, then carbon, then a run of heavier elements each burning faster than the last, until the core is iron and fusion can release nothing more.
NEXT The iron core collapses in about a second and the rest of the star is thrown off at a tenth of the speed of light. For a few weeks it outshines the galaxy it is in.
EVERY STAGE ON THIS TRACK
- COLLAPSING CLOUDtook about twenty thousand years
- A cold clump of gas and dust falls in on itself and heats as it falls. It stops being a cloud and starts being a star at the moment its core is hot enough to fuse hydrogen.
- MAIN SEQUENCElasted about three million years
- Hydrogen fuses to helium in the core, and the outward push of that exactly balances the star's own weight. This is the long, steady stretch — nine-tenths of a star's life — and it ends when the core's hydrogen is gone.
- SUPERGIANTabout three hundred thousand years of itNOW
- The same swelling, on a star heavy enough to keep going: helium, then carbon, then a run of heavier elements each burning faster than the last, until the core is iron and fusion can release nothing more.
- SUPERNOVAbright for weeks, over in a second
- The iron core collapses in about a second and the rest of the star is thrown off at a tenth of the speed of light. For a few weeks it outshines the galaxy it is in.
- BLACK HOLEfor the rest of time
- Nothing the core could be made of is stiff enough to stop the collapse, so it does not stop. What remains is a region of space that light cannot leave.
- HOW FIRM No mass has been measured for this star, and past the main sequence its temperature no longer implies one — a red giant of one solar mass and a red supergiant of fifteen are the same colour. The figure above comes from its total output instead, and is unlikely to be better than a factor of two.
- ALSO Its hydrogen envelope has already been driven off by its own wind, which is a late and short-lived condition and one that only the heaviest stars reach.
Which stage CF Cir is in was read from its catalogued class, its temperature and its total output at every wavelength — not from its brightness in visible light alone, which understates a cool star by a factor of several. The mass it started with is about thirty times the Sun's mass, from its luminosity, and that mass is what chooses the track. Every span of time here comes from the standard relation between a star’s mass and how long its fuel lasts, rounded to a single figure. They are orders of magnitude and none of them is a date.
CATALOG DATA
] 15 FIELDSThe raw catalogue values, as the source published them, with the error bars where one was published — sorted by what each set of figures is about rather than by the order they happened to be stored in.
WHAT KIND OF THING IT IS
What the object is in itself, rather than how it happens to look from here.
- Spectral type
- Surface temperature
- 23 750
- Luminosity
- 0.552586
- Radius
- 8.591
- Surface gravity (log g)
- Variability
- Wolf-Rayet star with variable emission
- Variability type ()
- WR
HOW BRIGHT IT IS
What the light adds up to, measured through one filter at a time. A magnitude is a brightness on a backwards scale — the smaller the number, the brighter the object.
- Variable magnitude, brightest
- Variable magnitude, faintest
WHERE IT IS AND HOW IT MOVES
Position, motion across the sky and the size it covers on it. These are measurements of the object as seen from here, so every one of them depends on where here is.
- Proper motion (RA)
- −4.32
- Proper motion (Dec)
- −0.34
- 0
OTHER NAMES AND NUMBERS
The identifiers other catalogues file this object under, for anyone joining this data to theirs.
- Variable-star designation
- CF Cir
WHERE THESE FIGURES CAME FROM
Which catalogue, paper or model each of the fields above was read from, where the source named one.
- Spectral type from
- SIMBAD (2006A&A...457.1015H, quality C)
- Stellar parameters from
- Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4) — low confidence: above 7,500 GSP-Phot's temperature and extinction are degenerate; Gaia's classifier calls the source a binary, which GSP-Phot fitted as one star
ALSO KNOWN AS
] 2 DESIGNATIONS- HIP HIP 69445
- Variable star CF Cir
LOOK IT UP ELSEWHERE
] 3 SERVICESEach link carries the identifier printed beside it. Nothing on this page is a measurement of our own, so a number that disagrees with one of these is worth reporting — and a service that has never catalogued this object under this name will say so plainly.
- SIMBADHIP 69445
Cross-identifications, measured values and the reference behind each of them.
- ADSobject:"HIP 69445"
Papers indexed against this object rather than against the string, newest first.
- VizieR5″ around 213.2647 -65.4480
Every published table with a row at this position, searched by coordinates rather than by name.
CITE THIS PAGE
] DR1This page is live and its numbers move when an upstream refreshes, so the citation names the release the rows belong to rather than the day you read them. The release itself is frozen, republished as a bundle, and is what a data-availability statement should point at.
SpaceCatalog. CF Cir [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hip-69445
@misc{spacecatalog_hip-69445,
author = {{SpaceCatalog}},
title = {{CF Cir}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/hip-69445},
note = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}
}The values above were taken from HYG Database v4.1 — CC-BY-SA-4.0. Citing this page does not replace citing that catalogue, and its licence is share-alike: the terms reach whatever you build from these rows.
That catalogue asks for this acknowledgement: HYG Database v4.1, Astronexus (github.com/astronexus/HYG-Database). Fields derived from it stay under CC BY-SA 4.0.
The stellar parameters marked as a Gaia DR3 model fit were taken from Gaia DR3 astrophysical parameters (GSP-Phot and FLAME), credit ESA/Gaia/DPAC, under CC BY-NC 3.0 IGO. ESA’s terms and requested acknowledgement: Credit: ESA/Gaia/DPAC. Licence: CC BY-NC 3.0 IGO, https://creativecommons.org/licenses/by-nc/3.0/igo/, non-commercial use only; commercial use needs ESA's prior authorisation. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. Cite Gaia Collaboration 2016, A&A 595, A1 (2016A&A...595A...1G) and Gaia Collaboration 2023, A&A 674, A1 (2023A&A...674A...1G).