HJ 4093

HJ 4093
Location of HJ 4093 (circled)
Observation data
Epoch J2000      Equinox ICRS
Constellation Puppis
HD 71487
Right ascension 08h 26m 17.7301s
Declination −39° 03′ 32.258″
Apparent magnitude (V) 6.49±0.01
(6.588 + 8.96)
primary eclipse: 6.98
secondary ecl.: 6.66
HD 71488
Right ascension 08h 26m 18.3057s
Declination −39° 03′ 36.747″
Apparent magnitude (V) 7.40
(7.900 + 8.10)
Characteristics
HD 71487
Evolutionary stage Main sequence
Spectral type B9V + A7V
B−V color index −0.11
Variable type Eclipsing binary
HD 71488
Evolutionary stage Main sequence
Spectral type A5V + A6V
B−V color index +0.30
Astrometry
HD 71487
Radial velocity (Rv)+25.4±0.6 km/s
Proper motion (μ) RA: −7.896 mas/yr
Dec.: +5.975 mas/yr
Parallax (π)5.7991±0.0304 mas
Distance562 ± 3 ly
(172.4 ± 0.9 pc)
Absolute magnitude (MV)+0.258±0.409
HD 71488
Proper motion (μ) RA: −6.1±2.0 mas/yr
Dec.: +10.4±2.9 mas/yr
Position (relative to HD 71487)
ComponentHD 71488
Epoch of observation2015
Angular distance8.1″
Position angle124°
Orbit
PrimaryHD 71487 A
SecondaryHD 71487 B
Period (P)1.2569956(9) days
Semi-major axis (a)0.03956±0.00023 au
(8.51±0.05 R☉)
Eccentricity (e)0.127±0.027
Inclination (i)81.33±0.20°
Semi-amplitude (K1)
(primary)		109.9±0.9 km/s
Semi-amplitude (K2)
(secondary)		232.1±1.5 km/s
Orbit
PrimaryHD 71488 A
SecondaryHD 71488 B
Period (P)101.3±3.8 years
Semi-major axis (a)0.179±0.012"
(34.4 au)
Eccentricity (e)0.054±0.041
Inclination (i)155±13°
Longitude of the node (Ω)47±71°
Periastron epoch (T)1976.23±13.06
Argument of periastron (ω)
(secondary)		318±74°
Details
HD 71487 A
Mass3.58±0.11 M☉
Radius2.17±0.03 R☉
Luminosity133±24 L☉
Surface gravity (log g)4.3±0.1 cgs
Temperature13,300±500 K
Metallicity [Fe/H]−0.02±0.01 dex
Rotation1.32 days
Rotational velocity (v sin i)65±5 km/s
Age20 Myr
HD 71487 B
Mass1.68±0.09 M☉
Radius1.51±0.06 R☉
Luminosity6.2±2.2 L☉
Surface gravity (log g)4.2±0.1 cgs
Temperature7,400±500 K
Metallicity [Fe/H]−0.08±0.03 dex
Rotational velocity (v sin i)64±2 km/s
Age20 Myr
HD 71488 A
Mass2.0 M☉
Age20 Myr
HD 71488 B
Mass1.8 M☉
Age20 Myr
Other designations
HJ 4093, B 1605, CD−38°4462, HIP 41361, CCDM J08263-3904, WDS J08263-3904
HD 71487: NO Puppis, HR 3327, SAO 199222, TYC 7661-4332-1
HD 71488: HR 3328, SAO 199224, TYC 7661-4332-2
Database references
SIMBADHD 71487
HD 71488

HJ 4093 (WDS J08263-3904) is a star system in the constellation Puppis. It comprises HD 71487 and HD 71488, which together form a visual binary and are themselves close binary systems, making HJ 4093 a four-star system. They are separated by about 1,400 astronomical units, having an estimated orbital period in the order of 10,000 years. The combined apparent magnitude is 6.07, making the system (faintly) visible to the naked eye only in ideal conditions, within places far from light pollution.

Parallax measurements by the Gaia spacecraft place HJ 4093 at a distance of 172±1 parsecs (562±3 light-years). The system is very young, at 20 million years old, and is part of an unnamed stellar association.

HD 71487

A light curve for NO Puppis, plotted from TESS data

HD 71487, also called HJ 4093 A and more frequently NO Puppis, is an eclipsing binary with an orbital period of 1.256 days. The overall apparent magnitude is 6.49, and during the primary (deeper) and secondary eclipse it drops to 6.98 and 6.66, respectively. The variability of this system was announced in 1972 by B. G. Jorgensen. When using a designation about the entire system (e.g. HJ 4093), the primary and secondary are referred to as Aa and Ab, respectively, but when using a specific designation (e.g. HD 71487) they may simply be called "A" and "B".

The components have stellar classifications of B8V and A7V, suggesting they are hot main sequence stars. NO Puppis A has 3.58 times the mass (M☉) and 2.17 times the radius (R☉), while NO Puppis B has 1.68 times the mass and 1.51 times the radius of the Sun. The effective temperature of A is 13,300 K, giving it the blue-white hue typical of a late B-type star, while that of component B is 7,400 K, giving it the whitish hue typical of a late A-type star. NO Puppis A lies in the instability strip of slowly pulsating B-type stars and is likely of this variable star class, while NO Puppis B lies in the instability strip of Delta Scuti variables and appears to exhibit δ Scuti-like pulsations.

The stars are separated by 8.5 R☉ and have an orbital eccentricity of 0.13, which is unusually high for such a close binary system, given that an orbit with such a separation would be expected to be nearly circular. At some point the system may have had several more components that were ejected due to gravitational perturbations, inducing a high eccentricity for this system.

HD 71488

HD 71488, also called HJ 4093 B, is an astrometric binary system with an apparent magnitude is 7.27. The components have an orbital period of 100 years. When using a designation about the entire system (e.g. HJ 4093), the primary and secondary are referred to as Ba and Bb, respectively, or sometimes as B and C, as in CCDM J08263-3904BC. When using a specific designation (e.g. HD 71488) they can be called simply "A" and "B". Based on its estimated absolute magnitude and mass–luminosity relations, HD 71488 A is expected to have a spectral type of A5V and an estimated mass of 2.0 M☉, while HD 71488 B would have a spectral type of A6V and an estimated 1.8 times the mass of the Sun, although direct observations give a combined spectral class of A2Va.

Notes

  1. ↑ The distance of 173.7173 parsecs published in Gaia DR3 is based on spectra rather than parallax.
  2. ↑ NO Puppis, while originally used only for HD 71487, is sometimes applied to the entire system, as in Erdem et al. (2025). In this situation, the components are named NO Puppis Aa and NO Puppis Ab.

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  3. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Erdem, Ahmet; Bakış, Volkan; Southworth, John; Rhodes, Michael D.; Aliçavuş, Filiz Kahraman; Budding, Edwin; Blackford, Mark; Banks, Timothy; Alexander, Murray (2025-08-07). "Absolute Parameters of Young Stars: NO Puppis". Publications of the Astronomical Society of Australia. 42 e120. arXiv:2508.05893. Bibcode:2025PASA...42..120E. doi:10.1017/pasa.2025.10080.
  5. 1 2 3 "NO Pup". General Catalogue of Variable Stars. Retrieved 2025-08-12.
  6. 1 2 3 4 Fabricius, C.; Høg, E.; Makarov, V. V.; Mason, B. D.; Wycoff, G. L.; Urban, S. E. (2002-03-01). "The Tycho double star catalogue". Astronomy & Astrophysics. 384 (1): 180–189. Bibcode:2002A&A...384..180F. doi:10.1051/0004-6361:20011822. ISSN 0004-6361.
  7. 1 2 3 Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. ISSN 0004-6256. HJ 4093's database entry at VizieR.
  8. ↑ "VSX : Detail for V0410 Pup". vsx.aavso.org. Retrieved 2025-08-12.
  9. 1 2 Veramendi, M. E.; González, J. F. (2014-03-01). "Spectroscopic study of early-type multiple stellar systems - I. Orbits of spectroscopic binary subsystems". Astronomy & Astrophysics. 563: A138. Bibcode:2014A&A...563A.138V. doi:10.1051/0004-6361/201322840. hdl:11336/4892. ISSN 0004-6361.
  10. 1 2 "HD 71487". SIMBAD. Centre de données astronomiques de Strasbourg.
  11. 1 2 3 "HD 71488". SIMBAD. Centre de données astronomiques de Strasbourg.
  12. 1 2 3 Grønbech, B. (1976). "Four color photometry of eclipsing binaries. V: Photometric elements of NO Puppis". Astronomy and Astrophysics. 50: 79–84. Bibcode:1976A&A....50...79G. ISSN 0004-6361.
  13. ↑ "Limiting Magnitude | COSMOS". astronomy.swin.edu.au. Retrieved 2025-06-01.
  14. ↑ Tokovinin, A. A.; Chalabaev, A.; Shatsky, N. I.; Beuzit, J. L. (1999). "A near IR adaptive optics search for faint companions to early-type multiple stars". Astronomy and Astrophysics. 346: 481–486. Bibcode:1999A&A...346..481T. ISSN 0004-6361.
  15. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 12 August 2025.
  16. ↑ Jorgensen, B. G. (March 14, 1972). Written at Budapest. "HR 3327 - an Eclipsing Binary with Eccentric Orbit" (PDF). Information Bulletin on Variable Stars. 641. Konkoly Observatory: 1. Bibcode:1972IBVS..641....1J.
  17. 1 2 "The Colour of Stars". Australia Telescope, Outreach and Education. Commonwealth Scientific and Industrial Research Organisation. December 21, 2004. Archived from the original on 2013-12-03. Retrieved 2012-01-16.
  18. ↑ Gray, R. O.; Garrison, R. F. (1987). "The Early A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation". The Astrophysical Journal Supplement Series. 65: 581. Bibcode:1987ApJS...65..581G. doi:10.1086/191237.