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A New Group of Dust-Forming Hot Stars Anatoly Miroshnichenko o Observatory (Saint-Petersburg, Russia) anck-Institut fur Radioastronomie (Bonn, Ge sity of Toledo (Ohio, USA)

A New Group of Dust-Forming Hot Stars

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A New Group of Dust-Forming Hot Stars. Anatoly Miroshnichenko. Pulkovo Observatory (Saint-Petersburg, Russia) Max-Planck-Institut fur Radioastronomie (Bonn, Germany) University of Toledo (Ohio, USA). Collaborators. Main Subject. Dust-Forming Stars. - PowerPoint PPT Presentation

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Page 1: A New Group of Dust-Forming Hot Stars

A New Group of Dust-FormingHot Stars

Anatoly Miroshnichenko

Pulkovo Observatory (Saint-Petersburg, Russia)

Max-Planck-Institut fur Radioastronomie (Bonn, Germany)

University of Toledo (Ohio, USA)

Page 2: A New Group of Dust-Forming Hot Stars

Collaborators

Valentina Klochkova, Vladimir Panchuk,

Eugene Chentsov, Maxim Yushkin

Anatoly Kusakin

Special Astrophysical Observatory of the Rus. Acad. Sciences, Russia

GAISh, Russia

Karen Bjorkman U. of Toledo, OH, USA

Richard Rudy, David Lynch, Steve Mazuk, Catherine Venturini

Aerospace Corp., CA, USA

Richard Gray Appalachian State U., NC, USA

Nadine Manset CFHT Corp., Canada

Kenesken Kuratov Fesenkov Astrophys. Inst., Казахстан

Kenneth Hinkle NOAO, AZ, USA

Richard Puetter U.of CA @ San Diego,USA

Thomas Gandet Lizzard Hollow Obs., AZ, USA

Brad Perry NASA Langley Center, VA, USA

Hugo Levato, Monica Grosso Complejo El Leoncito, Argentina

Page 3: A New Group of Dust-Forming Hot Stars

Main Subject

Dust-Forming Stars

circumstellar interstellar circumstellar

Cool Stars

Teff ~ 3000 K

+

Strong Outflow

Hot stars

Teff 10000 K

+

Shielding from UV

Colliding Winds

AGB & post-AGB

Dust

Tsub ~ 1500 K

WR, LBV с L/L > 105

Page 4: A New Group of Dust-Forming Hot Stars

Outline

• Early-Type Stars with Circumstellar Dust

• B[e] Stars

• Properties of B[e] Stars with Warm Dust

• Search for New Candidates and Results of the Initial Observations

• Nature and Evolutionary State

• Conclusions

Page 5: A New Group of Dust-Forming Hot Stars

Objects with Circumstellar Dust which Include a Hot Star

• Herbig Ae/Be stars (warm & cold dust)• Vega-type stars (cold dust)• Symbiotic Stars (M-giant + OB-subdwarf, white dwarf,

or neutron star; warm dust)• VV Cep stars (M-supergiant + OB dwarf ?; warm dust)• Wolf-Rayet stars (carbon-rich or binary; warm dust)• Luminous Blue Variables (cold dust)• Proto-Planetary & Planetary Nebulae (cold dust)• B[e] stars

Page 6: A New Group of Dust-Forming Hot Stars

B[e] Stars: History of StudiesDiscovery: Allen & Swings (1976, A&A, 47, 293)

65 objects with forbidden lines and IR excesses at =2 m

Possible explanations for the phenomenon:• Formation of a Planetary Nebula• Interaction of an OB star with a cool companion• Direct ejection of matter by a massive OB star

Follow up classification: Herbig Ae/Be stars (7), LBV (3), PNe (17), symbiotic (8), supergiants (7)

28 objects – uncertain classification

Page 7: A New Group of Dust-Forming Hot Stars

Additions and Systematization

Lists of similar objects• Carlson & Henize (1979, Vistas in Astronomy, 23 , 213):

20 early-type stars with strong emission-line spectra• Dong & Hu (1991, Chin. A&A, 15, 275): ~200 early-type

stars with strong IR-excesses (IRAS,V-[25] > 8 mag)

Systematization AttemptLamers et al. (1998, A&A, 340, 117) – 5 categories of

B[e] stars: sgB[e], pmsB[e], cPNB[e], SymbB[e], unclB[e]

New group of unclB[e] – B[e] stars with warm dust B[e]WD

Page 8: A New Group of Dust-Forming Hot Stars

IRAS color-color diagram

- B[e]WD, - Ае/Ве stars, - Vega-type stars, - symbiotic stars, ++ - VV Cep

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B[e] Stars with Warm Dust (B[e]WD)

Selection Criteria:Spectra: early-type + strong Balmer emission lines

IRAS colors: 0.5 < lg F12/F25 < +0.1

1.1 < lg F60/F25 < 0.3

Presentation as a group:

Sheikina, Miroshnichenko, & Corporon 1999 (IAU Coll. 175, Alicante, Spain) - 11 objects

Miroshnichenko, Bjorkman, Chentsov, Klochkova 2002 (IAU Coll. 187, Florida, USA) - 19 objects

Miroshnichenko et al. 2004 (203 AAS Meeting, Atlanta, USA) – 19 objects + 28 candidates

Page 10: A New Group of Dust-Forming Hot Stars

ObservationsTelescope Observatory Type of data

6-m SAO, Russia opt.spectra, R=15000-60000

3.6-m CFHT, USA opt.spectra, R=60000

8-m

3-m

3-m

Gemini, Chile

Lick Obs., USA

NASA IRTF, USA

IR spectra, 2.5m, R~75000

IR spectra, =0.82.5 m, R~300

IR spectra, =314 m, R~600

2.1-m McDonald Obs., USA opt.spectra, R=60000

2.1-m Compl. El Leoncito, Argentina opt.spectra, R=10000-15000

1.5-m Tenerife, Spain JHK photometry

1-m Tien-Shan Obs., Kazakhstan UBVRIJHK photometry

0.5&0.75-m SAAO, South Africa UBVRIJHKL photometry

0.8-m Dark Sky Obs., USA opt.spectra, R~3000

0.5-m

0.3-m

Tien-Shan Obs., Kazakhstan

Lizard Hollow Obs., USA

WBVR photometry

UBVRI photometry

Page 11: A New Group of Dust-Forming Hot Stars

Properties of B[e]WDName IRAS V Sp.T. E(B-V) Lg L/L D (kpc) EW(H)

AS 78 03549+5602 11.30.1 B2/4 0.9 3.9 0.1 2.5 115

CI Cam 04156+5552 9.011.6 B0/2+? 1.1 5.0 0.5 46 250

HD 45677 062591301 7.68.5 B2 0.2 3.5 0.4 0.5 170

HD 50138 064910654 6.56.8 B5 0.15 2.9 0.2 0.3 60

AS 160 073702438 10.90.1 B1 0.7 4.0 0.1 4.0: 300

Hen3-140 081285000 10.1 B2/8 0.3 3.1 0.2 2.0

Hen3-298 093505314 10.1 B3 1.3 5: 34 232

Hen3-303 093695406 13.1: B 34

HD 85567 094896044 8.6 B2 0.4 4.0 0.3 1.5 31

CPD57 2874 101365736 10.1 B3/5 1.9 5.7: 2.5

CPD52 9243 160315255 10.3 B3/4 1.8 5.7 0.3 4.9 60

HD 327083 171174016 9.70.1 B1/2+F 1.8 5.00.4 12 36

Hen3-1398 172133841 10.6 O9 1.1 5.3 0.2 3.3

MWC 300 182670606 11.60.2 B1 1.2 5.10.1 1.8 145

MWC 623 19545+3058 10.70.2 B2+K 1.4 4.1: 2.4: 122

AS 381 20047+3305 14.4 B1+K 2.2 4.9 0.2 4.0 80

MWC 342 20212+3920 10.210.9 B1/2 1.4 4.1 0.4 1.0 170220

V669 Cep 22248+6058 12.20.2 B5+K 0.9 2.7 0.3 11.5 66187

MWC 657 22407+6008 12.5 B1 1.6 3.7 0.3 2.0 180

Page 12: A New Group of Dust-Forming Hot Stars

Spectral Energy Distribution

Page 13: A New Group of Dust-Forming Hot Stars

Photometric Properties

Frequently observed objects:HD 45677, HD 50138, MWC 300, MWC 342, CI Cam

Variability Types:• Short-term irregular : V ~ 0.1 – 0.5 mag

• Long-term gradual brightness changes : V ~ 0.5 – 2 mag (MWC 342, HD 45677)

• Short-term outbursts : V ~ 3 mag (CI Cam, 1998 March 31)

• Cyclic: from weeks to years

• Near-IR variations: K ~ 0.5 mag

Page 14: A New Group of Dust-Forming Hot Stars
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Spectral Properties

• H line profiles are mostly double-peaked

• Single- or double-peaked narrow metallic emission lines (FWHM ~ 100 km s-1)

• Strong and variable Balmer emission lines

• Forbidden lines [O I] 6300 & 6364A, [N II] 5577, 6348, & 6384A, sometimes [S III] 6312A

Page 18: A New Group of Dust-Forming Hot Stars

Spectrral Variations

Page 19: A New Group of Dust-Forming Hot Stars

H Line Profiles

Page 20: A New Group of Dust-Forming Hot Stars

Absorption Lines

Page 21: A New Group of Dust-Forming Hot Stars

IR Spectra

Page 22: A New Group of Dust-Forming Hot Stars

Basic Physical Parameters

• Spectral Type of the Hot Companion: O9-B8• Spectral Type of the Cool Companion : F, K• Initial Mass : 2 - 40 M

• Luminosity: 500 – 106 L

• Circumstellar Gas distribution: disk-like• Circumstellar Dust distribution: not clear

(probably circumbinary disk)

Page 23: A New Group of Dust-Forming Hot Stars

Hertzsprung-Russell Diagram

Page 24: A New Group of Dust-Forming Hot Stars

Nature and Evolutionary State• Majority of (all?) objects – Main-Sequence and after

Known Binary systems:1. MWC 623: B2 V + K2 III (Zickgraf 2001, A&A, 375, 122)2. CI Cam: B[e] sg + black hole? (Miroshnichenko et al. 2002, A&A, 390, 627)3. AS 381: B1 I + K II-III (Miroshnichenko et al. 2002, A&A, 383, 171)4. V669 Cep: B5 V + K (Miroshnichenko et al. 2002, A&A, 388, 563)5. HD 327083: B1 I + F I (Miroshnichenko et al. 2003, A&A, 406, 673)

Suspected Binaries:1. MWC 342 (Miroshnichenko & Corporon 1999, A&A, 349, 126)2. MWC 657 (Miroshnichenko et al. 2000, A&AS, 147, 5)3. HD 85567 & Hen 1398 (Miroshnichenko et al. 2001, A&A, 371, 600)4. MWC 300 (Miroshnichenko et al. 2004, A&A, 417, 731)

Objects with a Controversial State:1. HD 45677 & HD 50138 – suggested Herbig Ве stars

Page 25: A New Group of Dust-Forming Hot Stars

Enlarging the Group

1. Stars of the main group are relatively bright V ~ 912 mag, K ~ 37 mag, [12m]~ 03.5 mag. The IRAS sensitivity limit : ~ 6 mag

2. Large range of the luminosities3. Release of the deep sky surveys in 2003:

2MASS (JHK) and USNO-B1.0 (5 non-standard optical bands)

Basis for a new search for B[e]WD in the IRAS catalogs

Page 26: A New Group of Dust-Forming Hot Stars

Search Strategy & Difficulties

Selection criteria• Color-indices [12][25] & [25][60]• Close positions in the IRAS & 2MASS catalogs• Selection of the brightest 2MASS object in the IRAS

error box• Positional coincidence in the 2MASS & USNO catalogs

Difficulties• Selection criteria are only positional & photometric• Separation of reddened hot stars from cool stars• Confusion with RV Tau stars

Page 27: A New Group of Dust-Forming Hot Stars

New Photometric Criterion

- RV Tau; + - cool stars

B[e]WD & new candidates

Page 28: A New Group of Dust-Forming Hot Stars

Search Results

4500 IR sources was found in the B[e]WD box• 60 objects satisfying the selection criteria were found

among 2500 objects with b 50 20 objects are thrown out after comparison with

dusty RV Tau stars• Initial observations of 40 B[e]WD candidates have

been started:

1. Multicolor optical photometry

2. Optical spectroscopy of low- and high-resolution

3. Low-resolution IR spectroscopy

Page 29: A New Group of Dust-Forming Hot Stars

Results of the Initial ObservationsSeptember 2003 – April 2004

Photometry• (WBVR, UBVRI) - 10 objects

Spectroscopy• DSO : 38005600 A, R~1800 – 10 objects• БТА : 52006600 A, R~60000 – 2 objects• CFHT : H, SiII 6347, Na D, R~100000 – 11 objects• Lick Obs. : 0.8 2.5m, R~1300 – 5 objects• NASA IRTF : 3 – 14 m, R~100 – 2 objects

It is shown that 8 objects are indeed B/A stars

2 new emission-line objects have been found

Page 30: A New Group of Dust-Forming Hot Stars

New Objects

IRAS 00470+6429

BTA USNO, 2MASS, IRTF

Page 31: A New Group of Dust-Forming Hot Stars

New ObjectsCFHT

Page 32: A New Group of Dust-Forming Hot Stars

Positional Distribution

- main group objects, - new candidates

Page 33: A New Group of Dust-Forming Hot Stars

Conclusions

• A new large group (61 objects to date) of hot stars with circumstellar dust is discovered

• Dust formation seems to be either on-going or has stopped recently

• Objects: either binary systems undergoing a rapid mass exchange or single stars with unusually strong winds

• Investigation of the group may lead to new ideas for evolutionary theories of single/binary stars and refinement of our understanding of dist formation