HD 141569

HD 141569 is an isolated[4] Herbig Ae/Be star[5] of spectral class A2Ve[6] approximately 320 light-years away in the constellation of Libra. The primary star has two red dwarf companions (orbiting each other) at about nine arcseconds. In 1999, a protoplanetary disk was discovered around the star. A gap in the disk speculate a possible extrasolar planet forming in the disk.

HD 141569

HD 141569 and its two companions taken by HST in 2002
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Libra
Right ascension 15h 49m 57.74785s[1]
Declination −03° 55′ 16.3430″[1]
Apparent magnitude (V) 7.12[2]
Characteristics
Spectral type A2 Ve
Astrometry
Proper motion (μ) RA: –18.41[1] mas/yr
Dec.: –19.25[1] mas/yr
Parallax (π)8.61 ± 0.60[1] mas
Distance320 ly
(98 pc)
Details
Mass3.1[3] M☉
Luminosity24.2[3] L☉
Temperature10,500[3] K
Age5 million[3] years
Other designations
BD−03° 3833, HIP 77542, SAO 140789
Database references
SIMBADdata

In November 2019, researchers studied HD 141569A (pre-main sequence B9.5 star) and made the first polarimetric detection of the inner ring circling the star. This may help better determine essential features of planetary development. According to the researchers, "Considering resolved imaging data from other high-contrast facilities, the HD 1415169A debris disc shapes up to be made of at least three, and potentially four nested rings, with spiral structures on the three spatially resolved rings [...] As such, it is an excellent laboratory for studying dynamically perturbed discs."[7][8]

Planetary system
The HD 141569 planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
Inner disk 86 AU — —
b (unconfirmed) — 225 — — — —
Outer disk 250 AU — —

Protoplanetary disk

In January 1999, NASA announced a protoplanetary disk around HD 141569. The Hubble Space Telescope showed that the disk appears to come in two parts (inner and outer). It superficially resembles the largest gap in Saturn's rings (known as the Cassini division).

The vast disk is 75 billion miles across (13 times the diameter of Neptune's orbit). The inner edge of the gap is 21 billion miles from the star. The relatively narrow gap lies approximately halfway between the inner and outer edges of the disk. Though already a fully formed star, HD 141569 is relatively young, probably only 1% through its lifetime as a stable star. The star is nearly three times more massive and 22 times brighter than the Sun. [9]

HD 141569 was first identified as a source that might have a disk in 1986 as a result of observations done with the Infrared Astronomical Satellite (IRAS). Thermal radiation emitted by the warmed dust was observed in images taken in June 2016 at the W. M. Keck Observatory.

Light from the central star which was reflected from dust particles in the disk was captured by Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) at a wavelength of 1.1 micrometres. At the distance of HD 141569, the crisp resolution of the telescope and camera combination reveals structures as small as 1 billion miles across. Dust disks surrounding newly forming stars are common, but only a small number of adult stars are known to have disks; of these, only a handful have been imaged. Astronomers believe these disks must form and/or be replenished when older rocks and debris collide and break up into small particles.

Possible planet

The gap in the disk leads to the conclusion of a protoplanet in formation around the star. The planet does not have to be in the gap, however. It could either be sweeping up the dust and rocks from the disk as it travels in its orbit around the star, or the gravity of the planet could knock the dust out of one part of the disk.[9]

See also

References
  1. van Leeuwen, Floor (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752v1, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357 Note: see VizieR catalogue I/311.
  2. Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. doi:10.1888/0333750888/2862. ISBN 978-0333750889.
  3. Wyatt, M. C.; et al. (July 2007), "Steady State Evolution of Debris Disks around A Stars", The Astrophysical Journal, 663 (1): 365–382, arXiv:astro-ph/0703608, Bibcode:2007ApJ...663..365W, doi:10.1086/518404
  4. Aarnio, Alicia N.; Weinberger, Alycia J.; Stassun, Keivan G.; Mamajek, Eric E.; James, David J. (2008). "A Survey for A Coeval, Comoving Group Associated with HD 141569". The Astronomical Journal. 136 (6): 2483. arXiv:0809.3289. Bibcode:2008AJ....136.2483A. doi:10.1088/0004-6256/136/6/2483. ISSN 1538-3881.
  5. Mendigutía, I.; Oudmaijer, R. D.; Mourard, D.; Muzerolle, J. (2017-01-11). "The compact Hα emitting regions of the Herbig Ae/Be stars HD 179218 and HD 141569 from CHARA spectro-interferometry". Monthly Notices of the Royal Astronomical Society. 464 (2): 1984–1989. arXiv:1610.00013. Bibcode:2017MNRAS.464.1984M. doi:10.1093/mnras/stw2515. ISSN 0035-8711.
  6. Murphy, Simon J.; Corbally, Christopher J.; Gray, Richard O.; Cheng, Kwang-Ping; Neff, James E.; Koen, Chris; Kuehn, Charles A.; Newsome, Ian; Riggs, Quinlin (2015). "An Evaluation of the Membership Probability of 212 λ Boo Stars. I. A Catalogue". Publications of the Astronomical Society of Australia. 32: e036. arXiv:1508.03633. Bibcode:2015PASA...32...36M. doi:10.1017/pasa.2015.34. ISSN 1323-3580.
  7. Starr, Michelle (2 December 2019). "Astronomers Have Detected a Familiar Feature in a Far-Away Solar System". ScienceAlert.com. Retrieved 2 December 2019.
  8. Bruzzone; et al. (2019). "Imaging the 44 AU Kuiper Belt-analogue debris ring around HD 141569A with GPI polarimetry". arXiv:1911.11814 [astro-ph.SR].
  9. "Hubble Views of Dust Disks and Rings Surrounding Young Stars Yield Clues". Hubble Space Telescope. NASA. 1999-01-08. Retrieved 2008-07-13.
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