AI Velorum

{{Starbox image

| image = 250px

| caption = A light curve for AI Velorum, plotted from TESS data

}}

{{Starbox observe

| epoch = J2000

| constell = Vela

| ra = {{RA|08|14|05.146}}

| dec = {{DEC|−44|34|32.85}}

| appmag_v = {{val|6.15|to|6.76}}

}}

{{Starbox character

| type =

| class = A9IV/V

| b-v = 0.18{{±|0.02}}

| variable = δ Sct

}}

{{Starbox astrometry

| radial_v = 9.0{{±|2.4}}

| prop_mo_ra = 26.222

| prop_mo_dec = 31.094

| pm_footnote =

| parallax = 9.9703

| p_error = 0.0191

| parallax_footnote =

| absmag_v = 1.61

}}

{{Starbox detail

| source =

| mass = 1.55

| radius = 2.86

| luminosity = 20

| temperature = 7,496{{±|255}}

| gravity = 3.85{{±|0.14}}

| metal_fe = −1.33

| rotational_velocity = 18

| rotation =

| age_myr = 479

}}

{{Starbox catalog

| names = {{odlist | V=AI Vel | CD=–44°4192 | GC=11221 | HD=69213 | HIP=40330 | SAO=219640 }}

}}

{{Starbox reference

| Simbad = AI+Vel

}}

AI Velorum is a variable star in the southern constellation of Vela, abbreviated AI Vel. It is a prototype for a class of high amplitude Delta Scuti variables. The apparent visual magnitude of this star fluctuates around 6.56, which is just bright enough to be dimly visible to the naked eye. The distance to AI Vel is approximately 327 light years based on parallax measurements, and it is drifting further away with a radial velocity of about 9 km/s.

The variability of this star was announced by E. Hertzsprung in 1931. He found a period of about {{convert|160|minutes|hours|2|disp=out|abbr=off}}, although he later found that period doubtful. In 1937, F. Zagar found irregular variations in the light curve. T. Walraven classified it as an RR Lyrae star in 1952 and suggested it may have two periods that interfered with each other. The primary period was found to be {{convert|0.111574|days|hours|3|disp=out|abbr=off}} while the secondary is {{convert|0.0862075|days|hours|3|disp=out|abbr=off}}; together their interference creates a beat period of {{convert|0.379182|days|hours|3|disp=out|abbr=off}}. The height of the maximum was found to be greater than the depth of the minimum, which may be the result of shockwaves that increase light emission.

As an RR Lyrae variable, AI Velorum should be a low mass, evolved star. However, M. Breger in 1977 noted the period and surface gravity showed a match with Delta Scuti stars of the same period. Together with the space velocity, these indicated it is instead a normal, high mass star belonging to the younger population I. By 1985, there was some evidence for an increase in the second period by one part in 10⁵. At least two additional periodicities were identified by Walraven and associates in 1992.

The stellar classification of AI Vel is A9IV/V, matching a slightly evolved star that is moving away from the main sequence. It is 479 million years old and is estimated to have 1.55 times the mass of the Sun. As a Delta Scuti variable, the brightness of the star ranges in magnitude from 6.15 down to 6.76. Evolutionary models published with Gaia Data Release 3 show it to be approaching the end of its main sequence life.

References

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{{citation

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{{citation | postscript=.

| title=A new variable star of short period

| last=Hertzsprung | first=E.

| journal=Bulletin of the Astronomical Institutes of the Netherlands

| volume=6 | page=147 | date=August 1931

| bibcode=1931BAN.....6..147H }}

{{citation | postscript=.

| title=Photographic photometry of AI Velorum on Johannesburg plates

| last=van Hoof | first=A.

| journal=Bulletin of the Astronomical Institutes of the Netherlands

| volume=8 | page=172 | date=June 1937

| bibcode=1937BAN.....8..172V }}

{{citation | postscript=.

| title=On the light-variation of AI Velorum

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| journal=Bulletin of the Astronomical Institutes of the Netherlands

| volume=11 | page=421 | date=July 1952

| bibcode=1952BAN....11..421W }}

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}}

{{citation | postscript=.

| title=Observations of the light and colour variations of AI Velorum using an acousto-optic filter photometer

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| journal=Astronomy and Astrophysics

| volume=151 | pages=403–407 | date=October 1985

| bibcode=1985A&A...151..403B }}

{{citation | postscript=.

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| journal=Monthly Notices of the Royal Astronomical Society

| volume=254 | pages=59–66 | date=January 1992

| doi=10.1093/mnras/254.1.59 | bibcode=1992MNRAS.254...59W | doi-access=free }}

}}

AI Velorum

References

Further reading