Catalogue record

HR 2491

9Alp CMa

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A bounded starter sample: 50 bright-star records from HEASARC BSC5P, including 23 records with identified double-star components and historical separations, plus 108 OpenNGC deep-sky records associated with Messier numbers.

These are static catalogue measurements, not current sky positions or a complete census. Double-star records may describe the same pair; a pair is not necessarily a gravitationally bound binary. Separation dates and companion position angles are not available.

Missing measurements are unknown, not zero. Sizes can come from different wavelength bands and do not guarantee an object’s visible extent. No observability or equipment-resolution prediction is made here.

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Stable source identifier: bsc5p:hr2491
Source object type: star
Catalogue right ascension: 101.2871 degrees
Catalogue declination: -16.7161 degrees
Recorded magnitude: -1.46 · V (BSC5P; retain code/uncertainty flags)
Uncertainty flag: None reported; source code: None reported
Catalogue major / minor axes: Not reported / Not reported
Components: AB
Historical component separation: 11.2 arcsec
Separation measurement epoch: Not reported
Companion position angle: Not reported

Coordinate interpretation

Verified coordinate frame: FK5
Frame equinox: J2000.0
Catalogue reference epoch: Julian year 2000.0
Individual observation epoch: Not reported
RA proper motion, including cosine of declination: -0.553 arcsec/year
Declination proper motion: -1.205 arcsec/year

The reference epoch describes when the catalogue position is expressed. It does not establish when individual observations were taken. Equinox describes the orientation of the coordinate axes.

Angular proper motion is available for a bounded calculation, but has not been applied here. No distance, radial velocity, perspective acceleration or companion orbit is inferred.

This page shows unchanged catalogue coordinates. It does not calculate current sky positions or observability.

Source and reuse: bsc5p

Hoffleit and Warren (1991), Bright Star Catalog, 5th revised preliminary edition; NASA/GSFC HEASARC

Original source / pinned release · NASA government-works; HEASARC free-use policy

Credit Hoffleit and Warren and NASA/GSFC HEASARC when reusing these records. Retain the source flags and historical measurement limitations.

Selection: Vmag <= 2.0, excluding 14 documented nonstellar HR identifiers
Retrieved: 2026-10-01T21:40:09.869946+00:00
Reviewed subset SHA256: 7fe926d80b535f9422ca81f8f3fee1d6422de29adaecfbd2f14b1a93fe5134b9

Original file hashes

bsc5p.tdat: e2b2f8e9d615426f9478f88061235976143d49d8b25c6c15df3f3661c7095b53

Coordinate-frame evidence

CDS VizieR · V/50/catalog

Exact source identifiers matched: 50. Evidence retrieved: 2026-10-01.

Pinned response SHA256: a3f83273ccaecf913a0d8e077413062c20ce1fc01ce890c80615a9572d5f1be9

Original source fields and flags

Original strings preserve missing values, photometric flags and per-field source codes. Blank means no value was supplied. No proper motion or companion position is calculated here.

ads: 5423
ads_comp: Not supplied
alt_name: 9Alp CMa
bii: -8.8903
bv_color: 0
bv_uncert: Not supplied
cdec: -164258
cdec_1950: -163947
class: 2315
cra: 064508.9
cra_1950: 064254.8
dec: -16.7161
dec_1900: -16.56666666789
dec_1950: -16.663
dm_cat: BD
dm_num: -16 1591
fk5: 257
glat: -8.88
glon: 227.22
hd: 48915
hr: 2491
ir_flag: I
lii: 227.23
m_cnt: 4
m_id: AB
m_mdiff: 10.3
m_sep: 11.2
multiple: Not supplied
name: HR 2491
note: *
par_code: Not supplied
parallax: 0.375
pmdec: -1.205
pmra: -0.553
ra: 101.2871
ra_1900: 100.185833327
ra_1950: 100.7283
radvel: -8
radvel_comm: SBO
ri_code: Not supplied
ri_color: -0.03
rotvel: 13
rotvel_comm: Not supplied
rotvel_uncert: Not supplied
sao: 151881
spect_code: Not supplied
spect_type: A1Vm
ub_color: -0.05
ub_uncert: Not supplied
var_id: Not supplied
vmag: -1.46
vmag_code: Not supplied
vmag_uncert: Not supplied