HD 155448

HD 155448
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Scorpius
Right ascension 17h 12m 58.7680s[1]
Declination −32° 14′ 33.5690″[1]
Apparent magnitude (V) 8.72[2]
Characteristics
HD 155448 A
Evolutionary stage Main sequence
Spectral type B1 V
B−V color index −0.27±0.02
HD 155448Ba
Evolutionary stage main sequence star
Spectral type B6V
B−V color index −0.15±0.02[3]
HD 155448 Bb
Evolutionary stage main sequence star
Spectral type B9V[3]
B−V color index −0.08±0.02[3]
HD 155448 C
Evolutionary stage Main sequence
Spectral type B4 Ve[3]
B−V color index −0.19±0.02[3]
HD 155448 D
Evolutionary stage Main sequence
Spectral type B8 V[3]
B−V color index −0.11±0.02[3]
Astrometry
A
Proper motion (μ) RA: +2.551[4] mas/yr[4]
Dec.: –1.666[4] mas/yr[4]
Parallax (π)0.9566 ± 0.0440 mas
Distance3,400 ± 200 ly
(1,050 ± 50 pc)
B
Proper motion (μ) RA: +1.758[5] mas/yr[5]
Dec.: –1.520[5] mas/yr[5]
Parallax (π)0.8401 ± 0.0384 mas
Distance3,900 ± 200 ly
(1,190 ± 50 pc)
D
Proper motion (μ) RA: +2.491[6] mas/yr[6]
Dec.: –1.567[6] mas/yr[6]
Parallax (π)0.7837 ± 0.0263 mas
Distance4,200 ± 100 ly
(1,280 ± 40 pc)
Details[3]
A
Mass>7 M☉
Surface gravity (log g)4 cgs
Temperature25,000 K
Rotational velocity (v sin i)90±5 km/s
Ba
Mass5 M☉
Surface gravity (log g)4 cgs
Temperature14,000 K
Rotational velocity (v sin i)150±50 km/s
Bb
Mass3 M☉
Surface gravity (log g)4 cgs
Temperature10,000 K
Rotational velocity (v sin i)150±50 km/s
C
Mass6 M☉
Surface gravity (log g)4 cgs
Temperature16,000 K
Rotational velocity (v sin i)50±10 km/s
D
Mass3.5 M☉
Surface gravity (log g)4 cgs
Temperature12,000 K
Rotational velocity (v sin i)300±15 km/s
Other designations
CD–32°12461, HD 155448, HIP 84228, SAO 208540, WDS J17130-3215
Database references
SIMBADdata

HD 155448 is a quintuple star system consisting of 5 young B-type stars . With an apparent magnitude of 8.72,[2] it is too dim to be visible with the naked eye.

Parallax measurements from the Hipparcos spacecraft in 1997 give the system a distance of 1,976 light years with a margin of error larger than the parallax itself.[1] The New Hipparcos Reduction gives a distance of 6,272 light years, but still with a statistical margin of error larger than the parallax value.[7] Gaia parallaxes are available for the visible components. For component C, the Gaia Data Release 2 and Gaia Early Data Release 3 (EDR3) parallaxes are both negative and somewhat meaningless.[8][6] For components A, B, and D, the Gaia EDR3 parallaxes are 0.9566±0.0440 mas,[4] 0.8401±0.0384 mas,[5] and 0.7837±0.0263 mas[6] respectively, implying a distance around 4,000 light years.

Before 2011, this star was mistaken as either a Herbig Ae/Be star[9] or a post-AGB object.[10] When the system was studied in 2011, it was originally believed to contain only 4 stars (or at least more than 2 stars). In 2011, a study conducted at the European Southern Observatory in Chile concluded that the "B" star is actually a binary star, thus reclassifying it as a quintuple star system.[3] HD 155448 A, B, C, and D. Periods have been estimated at 27,000 years for Bab, 59,000 years for AB, 111,000 years for Ac, and 327,000 years for AD.[11] However, analysis in 2011 states that the stars aren't gravitationally bound to each other.[3]

All of the stars are currently on the ZAMS. At present the primary star has a mass greater than 7 solar masses and an effective temperature of 25,000 K, while the companions have masses ranging from 3-6 times the mass of the Sun, and temperatures ranging from 10,000-16,000 K.

  1. ^ a b c Cite error: The named reference Perryman1997 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  3. ^ a b c d e f g h i j Cite error: The named reference Schutz2011 was invoked but never defined (see the help page).
  4. ^ a b c d Cite error: The named reference edr3a was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference edr3b was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference edr3d was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference dr2c was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Vioque2018 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Luna2008 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference msc was invoked but never defined (see the help page).