V905 Cen
ILLUSTRATION FROM MEASURED TEMPERATURE · 4580 K · 12.9 L☉ · VARIABLE, MAG 10.48–10.67 · PERIOD 60.2 DAYS · PULSE COMPRESSED
OVERVIEW
] STARV905 Cen is a C red star in the constellation Centaurus, 1647 from Earth, shining at apparent magnitude 10.59 (). It is catalogued as HD 98767 and HIP 55448.
- WHAT IT IS
- Red star
- HOW FAR
- 1647
- 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 · 4580 K · 12.9 L☉ · VARIABLE, MAG 10.48–10.67 · PERIOD 60.2 DAYS
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. 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 what is in the frame is that whole neighbourhood seen from outside it, piled into a knot around the Sun. The rest of the sky from here is not something this catalogue knows.
OBSERVING
] FROM WHERE YOU AREWhat it takes to see V905 Cen 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 V905 Cen 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 ()
- 10.59 · within reach
APPARENT PLACE
] EQUINOX J2026.7Where 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
- 13.5
- PROPER MOTION SINCE
- 0.21
Computed for 2026-08-28 00:00 UT. Two things separate it from the catalogued position above: V905 Cen 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. Aberration and refraction are not included, and neither is parallax; each is under an arcminute, which is also about as well as the catalogued position is known. The same figure for any date.
VARIABILITY
] SEMIREGULAR PULSATING GIANT (POORLY DEFINED PERIODICITY)- RANGE, AS SAMPLED
- 10.48 – 10.67
- PERIOD
- 60.2 days
For this class the published period is a mean cycle time rather than an ephemeris: the star repeats on that timescale without keeping to it, so counting cycles from a past event would predict a date the star has no obligation to meet.
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 and the period are the General Catalogue of Variable Stars’s. These elements as data.
LIFE OF THIS STAR
] STAGE 3 OF 5V905 Cen is an orange giant near the end of its life; some time between the next few centuries and the next million years it will collapse and explode as a supernova, leaving a neutron star.
- COLLAPSING CLOUDtook about three hundred thousand years
- MAIN SEQUENCElasted about fifty million years
- GIANTcenturies to a million years leftNOW
- SUPERNOVAbright for weeks, over in a second
- NEUTRON STARfor 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 three hundred 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 fifty 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.
- GIANTcenturies to a million years leftNOW
- 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.
- NEUTRON STARfor the rest of time
- What is left of the core: a couple of solar masses in a ball the width of a city, so dense that its protons and electrons have been pressed into neutrons.
- HOW FIRM How long a red supergiant has left depends on which fuel its core is burning, and that cannot be seen from outside — it is read from the star's pulsation, by working out which of its periods is the whole star ringing rather than its surface churning. The reading is disputed for every one of these stars, including the most-watched of them: one way round the core is still on helium and there are of the order of a hundred thousand years to go, the other way round it is already on carbon and there are centuries. That is why the figure above is a span. Nothing measured so far closes it.
- ALSO It sits close to the dividing line, near eight times the Sun's mass, between the stars that end quietly as white dwarfs and the ones that explode. Nothing in this catalogue settles which side of it this star is on.
- ALSO Its class is one only an evolved star can have: the carbon on its surface was made in its own interior and dredged up, which is a thing that happens on the asymptotic giant branch and nowhere earlier.
Which stage V905 Cen 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 eight times the Sun's mass, from a published model fit, 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 — except the stage this star is in, which that relation cannot reach, and which is given as the range the published readings actually cover. They are orders of magnitude and none of them is a date.
CATALOG DATA
] 19 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
- 4576
- Luminosity
- 12.9062
- Luminosity (bolometric)
- 3284.1147
- Radius
- 79.528
- Mass
- 8.196
- Surface gravity (log g)
- Variability
- Semiregular pulsating giant (poorly defined periodicity)
- Variability type ()
- SRB
- Variability period
- 60.2
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.
- Colour index (B−V)
- 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)
- −5.65
- Proper motion (Dec)
- 5.75
- Radial velocity
- −9.6
OTHER NAMES AND NUMBERS
The identifiers other catalogues file this object under, for anyone joining this data to theirs.
- Variable-star designation
- V905 Cen
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 (1975MSS...C01....0H, quality D)
- Stellar parameters from
- Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)
ALSO KNOWN AS
] 3 DESIGNATIONS- HD HD 98767
- HIP HIP 55448
- Variable star V905 Cen
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.
- SIMBADHD 98767
Cross-identifications, measured values and the reference behind each of them.
- ADSobject:"HD 98767"
Papers indexed against this object rather than against the string, newest first.
- VizieR5″ around 170.3414 -55.7632
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. V905 Cen [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-98767
@misc{spacecatalog_hd-98767,
author = {{SpaceCatalog}},
title = {{V905 Cen}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/hd-98767},
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.