HM Sagittae

Last updated
HM Sagittae
HMSgeLightCurve.png
A light curve for HM Sagittae. The main plot shows 1-year averages of AAVSO visual band data. [1] The inset plot (adapted from Munari and Whitelock [2] ) shows near-infrared variability arising from the red giant's pulsations.
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Sagitta
Right ascension 19h 41m 57.080s [3]
Declination +16° 44′ 39.81″ [3]
Apparent magnitude  (V)10.99 [4]
Characteristics
Spectral type M7 [5]
Apparent magnitude  (pg)11.10 to 18 [6]
B−V color index 2.38 [4]
Variable type NC + M [6]
Astrometry
Proper motion (μ)RA: −0.443  mas/yr [3]
Dec.: −7.104  mas/yr [3]
Parallax (π)0.9735 ± 0.1033  mas [3]
Distance approx. 3,400  ly
(approx. 1,000  pc)
Details
Red giant
Radius 540 [7]   R☉
Luminosity 5,000 [8]   L☉
Temperature 3,000 [8]   K
White dwarf
Radius 0.08 [9]   R☉
Luminosity9,200 [9]   L☉
Temperature 200,000 [9]   K
Other designations
HM Sge, Nova Sge 1975, [10] SVS 2183 [11]
Database references
SIMBAD data

HM Sagittae is a dusty-type symbiotic nova in the northern constellation of Sagitta. [8] It was discovered by O. D. Dokuchaeva and colleagues in 1975 when it increased in brightness by six magnitudes (a factor of around 250 brighter). [12] The object displays an emission line spectrum similar to a planetary nebula and was detected in the radio band in 1977. [11] Unlike a classical nova, the optical brightness of this system did not rapidly decrease with time, although it showed some variation. It displays activity in every band of the electromagnetic spectrum from X-ray to radio. [13]

Observations in the infrared during 1978 showed this to be a very strong source with a spectrum that is consistent with a binary symbiotic system similar to V1016 Cyg. The cooler stellar component is emitting material that is then ionized by a hot component, with the emission spectrum coming from heated dust generated by the cooler star. [14] By 1983, the infrared emission of the system was shown to vary by a factor of 1.5 magnitudes in the K-band with a time scale of about 500 days. [15] High resolution spectral examination of the system in 1984 showed a bipolar outflow of matter with a velocity of 200 km/s. [13] A series of knots extend outward on both sides of the central star to an angular distance of 9 arcseconds. [16] The nebula surrounding the system shows a bipolar, S-shaped morphology, similar to R Aqr. [17]

The features of the system are consistent with a central red giant star being orbited by a compact object that is accreting matter from the giant. [13] The pair have an angular separation of 40±9  mas , with the axis aligned along a position angle of 130°±10°. Their physical separation is estimated at 50  astronomical units . [18] The giant component is most likely a Mira variable and measurements up to 1989 found a period of 527 days. [19] It is surrounded by a dusty shell that is mostly composed of silicates. [8] The compact object is a hot white dwarf with 70% of the mass of the Sun, [19] which is orbited by an accretion disk. The nova-like outburst of 1975 may have been generated by a burst of mass transfer from the giant to the white dwarf during the periastron passage of an eccentric orbit, leading to a thermonuclear outburst. [20]

Winds from both stars are colliding to produce a shock region that is a source of ultraviolet emission. [19] By 1985, a fading of the brightness and an increase in redness were observed, caused by dust obscuration. The hot component may be inhibiting dust formation around the giant except in the shadow region behind the star. This could explain observed individual dust obscuration events. [21]

Related Research Articles

<span class="mw-page-title-main">Chi Cygni</span> Star in the constellation Cygnus

Chi Cygni is a Mira variable star in the constellation Cygnus, and also an S-type star. It is around 500 light years away.

<span class="mw-page-title-main">V1500 Cygni</span> Star in the constellation Cygnus

V1500 Cygni or Nova Cygni 1975 was a bright nova occurring in 1975 in the constellation Cygnus. It had the second highest intrinsic brightness of any nova of the 20th century, exceeded only by CP Puppis in 1942.

<span class="mw-page-title-main">T Coronae Borealis</span> Recurrent nova in the constellation Corona Borealis

T Coronae Borealis, is a recurring nova in the constellation Corona Borealis. It was first discovered in outburst in 1866 by John Birmingham, although it had been observed earlier as a 10th magnitude star.

<span class="mw-page-title-main">V476 Cygni</span> Star in the constellation Cygnus

V476 Cygni or Nova Cygni 1920 was a nova which occurred in the constellation Cygnus in 1920. It was discovered by William Frederick Denning, an English amateur astronomer, at 09:30 GMT on 20 August 1920, at which time it had a magnitude of 3.7. It reached a peak brightness of magnitude 1.7 on 23 August 1920. Its quiescent brightness is magnitude 17.09.

<span class="mw-page-title-main">V1668 Cygni</span> Nova that appeared in 1978

V1668 Cygni was a nova that appeared in the northern constellation of Cygnus, situated a couple of degrees to the southeast of the star Rho Cygni. It was discovered by Canadian variable star observer Warren Morrison on September 10, 1978, and reached a peak brightness of around 6.22 apparent magnitude on September 12. The luminosity of the source at this time was about 100,000 times the brightness of the Sun, and likely remained at that level for several months. The expansion velocity of the nova shell was deduced through spectroscopy to be 1,300 km/s.

<span class="mw-page-title-main">Sakurai's Object</span> Star in the constellation Sagittarius

Sakurai's Object is a star in the constellation of Sagittarius. It is thought to have previously been a white dwarf that, as a result of a very late thermal pulse, swelled and became a red giant. It is located at the center of a planetary nebula and is believed to currently be in thermal instability and within its final shell helium flash phase.

Z Andromedae is a binary star system consisting of a red giant and a white dwarf. It is the prototype of a type of cataclysmic variable star known as symbiotic variable stars or simply Z Andromedae variables. The brightness of those stars vary over time, showing a quiescent, more stable phase and then an active one with a more pronounced variability and stronger brightening and/or dimming.

Symbiotic novae are slow irregular eruptive variable stars with very slow nova-like outbursts with an amplitude of between 9 and 11 magnitudes. The symbiotic nova remains at maximum for one or a few decades, and then declines towards its original luminosity. Variables of this type are double star systems with one red giant, which probably is a Mira variable, and one a hot compact object, with markedly contrasting spectra and whose proximity and mass characteristics indicate it as a symbiotic star. They are divided into D-type (dusty) or S-type (stellar), depending on whether the giant is a Mira variable or not.

FG Sagittae is a supergiant star in the constellation Sagitta at a distance of 4000 light-years. When first noted in 1943, it was identified to be a variable star, and it was found to be a hot, blue star of stellar spectral type B in 1955. Since then it has expanded and cooled, becoming a yellow G-type star by 1991, and then further cooling to become an orange K-type star. It started to pulsate when becoming an A-type star with a period of 15 days. This period later increased to over 100 days.

<span class="mw-page-title-main">WZ Sagittae</span> Variable star in the constellation Sagitta

WZ Sagittae is a cataclysmic dwarf nova star system in the constellation Sagitta. It consists of a white dwarf primary being orbited by a low mass companion. The white dwarf is about 0.85 solar masses while the companion is only 0.08 solar masses. This implies that the companion is a spectral class L2 star, although this has yet to be confirmed. The distance to this system has been determined by parallax, yielding a distance of 45.1 parsecs.

<span class="mw-page-title-main">NML Cygni</span> Star in the constellation Cygnus

NML Cygni or V1489 Cygni is a red hypergiant or red supergiant (RSG) in the constellation Cygnus. It is one of the largest stars currently known by radius, and is also one of the most luminous and massive cool hypergiants, as well as one of the most luminous stars in the Milky Way.

33 Cygni is a single star located 159 light years away in the northern constellation Cygnus. It is visible to the naked eye as a white-hued star with an apparent visual magnitude of 4.28. The star is moving closer to the Earth with a heliocentric radial velocity of −16 km/s. Eggen (1995) listed it as a proper motion candidate for membership in the IC 2391 supercluster.

<span class="mw-page-title-main">HD 316285</span> Star in the constellation Sagittarius

HDE 316285 is a blue supergiant star in the constellation Sagittarius. It is a candidate luminous blue variable and lies about 6,000 light years away in the direction of the galactic centre.

<span class="mw-page-title-main">CH Cygni</span> Variable star in the Cygnus constellation

CH Cygni is a red giant, variable, symbiotic binary in the constellation Cygnus. It is the nearest symbiotic star to Earth, and one of the brightest, making it an ideal candidate for study.

<span class="mw-page-title-main">V1794 Cygni</span> FK Comae Berenices variable in the constellation Cygnus

V1794 Cygni is a single variable star in the northern constellation Cygnus. It has the identifier HD 199178 from the Henry Draper Catalogue; V1794 Cygni is its variable star designation. With an apparent visual magnitude of 7.24, it's too dim to be visible with the naked eye but can be seen with binoculars. V1794 is located at a distance of 367 light-years (113 pc) based on parallax measurements, but is drifting closer to the Sun with a radial velocity of −31 km/s. It lies superimposed over a region of faint nebulosity to the west of the North American Nebula.

<span class="mw-page-title-main">V4332 Sagittarii</span>

V4332 Sagittarii is a nova-like event in the constellation of Sagittarius. It was discovered February 24, 1994 at an apparent visual magnitude of 8.9 by Japanese amateur astronomer Minoru Yamamoto from Okazaki, Aichi, then confirmed by K. Hirosawa. Initially designated Nova Sagittarii 1994 #1, it was given the variable star designation V4332 Sgr. A spectra of the event taken March 4 lacked the characteristic features of a classical nova, with the only emission lines being of the Balmer series. Subsequent spectra showed a rapid decline in luminosity and a change of spectral type over a period of five days. By 2003, the object was ~1500 times less luminous than at peak magnitude and showed a spectrum of an M-type star.

<span class="mw-page-title-main">U Sagittae</span>

U Sagittae is an eclipsing binary star system in the northern constellation of Sagitta. It has been actively studied since its discovery in 1901. The maximum apparent visual magnitude of this system is 6.50, which is near the lower limit of visibility to the naked eye. The system is located at a distance of approximately 868 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −17 km/s. It is positioned about 2° from the middle of the Collinder 399 asterism, but lies much further away than the purported member stars.

<span class="mw-page-title-main">PU Vulpeculae</span> Variable star in the constellation Vulpecula

PU Vulpeculae is a very slowly evolving symbiotic nova in the northern constellation of Vulpecula, abbreviated PU Vul. It is too faint to be visible to the naked eye, reaching a maximum apparent visual magnitude of 8.7 following a minimum of 16.6. The system is located at a distance of approximately 17,000 light years from the Sun based on parallax measurements.

<span class="mw-page-title-main">X Cygni</span> Variable star in the constellation Cygnus

X Cygni is a variable star in the northern constellation of Cygnus, abbreviated X Cyg. This is a Delta Cephei variable that ranges in brightness from an apparent visual magnitude of 5.85 down to 6.91 with a period of 16.386332 days. At it brightest, this star is dimly visible to the naked eye. The distance to this star is approximately 628 light years based on parallax measurements. It is drifting further away with a radial velocity of 8.1 km/s. This star is a likely member of the open cluster Ruprecht 173.

<span class="mw-page-title-main">SU Cygni</span> Variable star system in the constellation Cygnus

SU Cygni is a triple star system in the northern constellation of Cygnus, abbreviated SU Cyg. The primary component of the system is a classical Cepheid variable with a period of 3.8455473 days. The changing luminosity of this star causes the system to vary in brightness from a peak apparent visual magnitude of 6.44 down to magnitude 7.22 over the course of its cycle. The distance to this system is approximately 3,200 light years based on parallax measurements. It is a member of the Turner 9 open cluster of stars.

References

  1. ↑ "Download Data", aavso.org, AAVSO, retrieved 1 October 2021.
  2. ↑ Munari, U.; Whitelock, P. A. (March 1989), "Variable dust obscuration in the symbiotic Mira and very slow nova, HM Sge", Monthly Notices of the Royal Astronomical Society, 237: 45–50, Bibcode:1989MNRAS.237P..45M, doi: 10.1093/mnras/237.1.45P .
  3. 1 2 3 4 5 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  4. 1 2 Høg, E.; et al. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355: L27, Bibcode:2000A&A...355L..27H, doi:10.1888/0333750888/2862, ISBN   978-0333750889.
  5. ↑ Mürset, U.; Schmid, H. M. (1999), "Spectral classification of the cool giants in symbiotic systems", Astronomy and Astrophysics Supplement, 137 (3): 473, Bibcode:1999A&AS..137..473M, doi: 10.1051/aas:1999105 .
  6. 1 2 Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports , 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID   125853869.
  7. ↑ Taranova, O. G.; Shenavrin, V. I. (2000), "Infrared Photometry of the Symbiotic Novae V1016 Cyg and HM Sge in 1978-1999", Astronomy Letters, 26 (9): 600, Bibcode:2000AstL...26..600T, doi:10.1134/1.1307894, S2CID   120096176.
  8. 1 2 3 4 Sacuto, S.; Chesneau, O. (January 2009), "On the morphology of the compact dust shell in the symbiotic system HM Sagittae", Astronomy and Astrophysics, 493 (3): 1043–1048, arXiv: 0812.1896 , Bibcode:2009A&A...493.1043S, doi:10.1051/0004-6361:200810934, S2CID   14886524.
  9. 1 2 3 Schild, H.; Eyres, S. P. S.; Salama, A.; Evans, A. (2001), "ISO observations of symbiotic stars. I. HM Sge", Astronomy and Astrophysics, 378: 146, Bibcode:2001A&A...378..146S, doi: 10.1051/0004-6361:20011155 .
  10. ↑ "HM Sge", SIMBAD , Centre de données astronomiques de Strasbourg , retrieved 2022-02-09.
  11. 1 2 Feldman, P. A. (October 1977), "The Detection of Radio Emission from the New Optical Emission Variable HM Sagittae", Journal of the Royal Astronomical Society of Canada, 71: 386, Bibcode:1977JRASC..71..386F.
  12. ↑ Dokuchaeva, O. D. (October 1976), "A New Emission Object", Information Bulletin on Variable Stars, 1189: 1, Bibcode:1976IBVS.1189....1D.
  13. 1 2 3 Solf, J. (October 1984), "High-resolution observations of bipolar mass flow from the symbiotic star HM Sagittae", Astronomy and Astrophysics, 139: 296–304, Bibcode:1984A&A...139..296S.
  14. ↑ Puetter, R. C.; et al. (July 1978), "Infrared spectra of HM Sagittae and V1016 Cygni", Astrophysical Journal, 223: L93–L95, Bibcode:1978ApJ...223L..93P, doi: 10.1086/182736 .
  15. ↑ Taranova, O. G.; Iudin, B. F. (January 1983), "V1016 Cygni and HM Sagittae : binary stellar systems", Astronomy and Astrophysics, 117: 209–214, Bibcode:1983A&A...117..209T.
  16. ↑ Corradi, R. L. M.; et al. (August 1999), "The optical nebulae around the symbiotic Miras He 2-147, HM Sagittae and V1016 Cygni", Astronomy and Astrophysics, 348: 978–989, Bibcode:1999A&A...348..978C.
  17. ↑ Hack, Warren J.; Paresce, Francesco (November 1993), "Imaging the Bipolar Nebula around HM Sagittae", Publications of the Astronomical Society of the Pacific, 105: 1273, Bibcode:1993PASP..105.1273H, doi: 10.1086/133307 , S2CID   121305970.
  18. ↑ Eyres, S. P. S.; et al. (April 2001), "The Inner Nebula and Central Binary of the Symbiotic Star HM Sagittae", The Astrophysical Journal, 551 (1): 512–519, arXiv: astro-ph/0101189 , Bibcode:2001ApJ...551..512E, doi:10.1086/320086, S2CID   119332145.
  19. 1 2 3 Sanad, M. R.; Abdel-Sabour, M. A. (April 2020), "Spectral Behavior of the Symbiotic Nova HM Sge in the Ultraviolet", Revista Mexicana de Astronomía y Astrofísica, 56: 63–69, Bibcode:2020RMxAA..56...63S, doi: 10.22201/ia.01851101p.2020.56.01.08 .
  20. ↑ Chochol, D.; et al. (February 2004), "Long-term photometry of the symbiotic nova HM Sge", Contributions of the Astronomical Observatory Skalnaté Pleso, 34 (1): 5–19, Bibcode:2004CoSka..34....5C.
  21. ↑ Munari, U.; Whitelock, P. A. (March 1989), "Variable dust obscuration in the symbiotic Mira and very slow nova, HM Sge.", Monthly Notices of the Royal Astronomical Society, 237: 45P–50P, Bibcode:1989MNRAS.237P..45M, doi: 10.1093/mnras/237.1.45P .

Further reading

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.