HD 155448

{{Short description|Quintuple star system in the constellation Scorpius}}

{{Starbox begin

| name = HD 155448

}}

{{Starbox observe

| constell = Scorpius

| epoch = J2000.0

| equinox = J2000.0 (ICRS)

| ra = {{RA|17|12|58.7680}}

| dec = {{DEC|-32|14|33.5690}}

|appmag_v = 8.72

}}

{{Starbox character

| type = Main sequence

| class = B1 V

| component1 = HD 155448 A

| b-v = {{val|−0.27|0.02}}

}}

{{Starbox character|no_heading = yes

| type = main sequence star

| class = B6V

| b-v = {{val|−0.15|0.02}}

| class2 = B9V

| type2 = main sequence star

| b-v2 = {{val|−0.08|0.02}}

| component1 = HD 155448Ba

| component2 = HD 155448 Bb

}}

{{Starbox character|no_heading = yes

| type = Main sequence

| class = B4 Ve

| component1 = HD 155448 C

| b-v = {{val|−0.19|0.02}}

}}

{{Starbox character|no_heading = yes

| type = Main sequence

| class = B8 V

| component1 = HD 155448 D

| b-v = {{val|−0.11|0.02}}

}}

{{Starbox astrometry

| component1 = A

| prop_mo_ra = +2.551

| prop_mo_dec = –1.666

| parallax = 0.9566

| p_error = 0.0440

| pm_footnote =

}}

{{Starbox astrometry|no_heading=y

| component1 = B

| prop_mo_ra = +1.758

| prop_mo_dec = −1.520

| parallax = 0.8401

| p_error = 0.0384

| pm_footnote =

}}

{{Starbox astrometry|no_heading=y

| component1 = D

| prop_mo_ra = +2.491

| prop_mo_dec = −1.567

| parallax = 0.7837

| p_error = 0.0263

| pm_footnote =

}}

{{Starbox detail

| source =

| component1 = A

| mass = >7

| gravity = 4

| temperature = 25,000

| rotational_velocity = {{val|90|5}}

}}

{{Starbox detail|no_heading = yes

| source =

| component1 = Ba

| mass = 5

| gravity = 4

| temperature = 14,000

| rotational_velocity = {{val|150|50}}

| component2 = Bb

| mass2 = 3

| gravity2 = 4

| temperature2 = 10,000

| rotational_velocity2 = {{val|150|50}}

}}

{{Starbox detail|no_heading = yes

| source =

| component1 = C

| mass = 6

| gravity = 4

| temperature = 16,000

| rotational_velocity = {{val|50|10}}

}}

{{Starbox detail|no_heading = yes

| source =

| component1 = D

| mass = 3.5

| gravity = 4

| temperature = 12,000

| rotational_velocity = {{val|300|15}}

}}

{{Starbox catalog

| names = {{odlist|CD= −32°12461|HD = 155448|HIP = 84228|SAO = 208540|WDS = J17130-3215}}

}}

{{Starbox reference

| Simbad = HD+155448

| Simbad2 = HD+155448B |sn2=B

| Simbad3 = TIC+46749972 |sn3=C

| Simbad4 = TIC+46749952 |sn4=D

}}

{{Starbox end}}

HD 155448 is a quintuple star system consisting of 5 young B-type stars . With an apparent magnitude of 8.72, 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. 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. 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. For components A, B, and D, the Gaia EDR3 parallaxes are {{val|0.9566|0.0440|ul=mas}}, {{val|0.8401|0.0384|ul=mas}}, and {{val|0.7837|0.0263|ul=mas}} respectively, implying a distance around 4,000 light years.

Before 2011, this star was mistaken as either a Herbig Ae/Be star or a post-AGB object. 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. 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. However, analysis in 2011 states that the stars are not gravitationally bound to each other.

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.