2018A&A...615A..30S


Query : 2018A&A...615A..30S

2018A&A...615A..30S - Astronomy and Astrophysics, volume 615A, 30-30 (2018/7-1)

Clues about the scarcity of stripped-envelope stars from the evolutionary state of the sdO+Be binary system φ Persei.

SCHOOTEMEIJER A., GOTBERG Y., DE MINK S.E., GIES D. and ZAPARTAS E.

Abstract (from CDS):

Stripped-envelope stars form in binary systems after losing mass through Roche-lobe overflow. They bear astrophysical significance as sources of UV and ionizing radiation in older stellar populations and, if sufficiently massive, as stripped supernova progenitors. Binary evolutionary models predict that they are common, but only a handful of subdwarfs with B-type companions are known. The question is whether a large population of such systems has evaded detection as a result of biases, or whether the model predictions are wrong. We reanalyze the well-studied post-interaction binary φ Persei. Recently, new data have improved the orbital solution of the system, which contains an ∼1.2M stripped-envelope star and a rapidly rotating ∼9.6M Be star. We compare with an extensive grid of evolutionary models using a Bayesian approach and constrain the initial masses of the progenitor to 7.2±0.4M for the stripped star and 3.8±0.4M for the Be star. The system must have evolved through near-conservative mass transfer. These findings are consistent with earlier studies. The age we obtain, 57±9Myr, is in excellent agreement with the age of the α Persei cluster. We note that neither star was initially massive enough to produce a core-collapse supernova, but mass exchange pushed the Be star above the mass threshold. We find that the subdwarf is overluminous for its mass by almost an order of magnitude, compared to the expectations for a helium core burning star. We can only reconcile this if the subdwarf resides in a late phase of helium shell burning, which lasts only 2-3% of the total lifetime as a subdwarf. Assuming continuous star formation implies that up to ∼50 less evolved, dimmer subdwarfs exist for each system similar to φ Persei, but have evaded detection so far. Our findings can be interpreted as a strong indication that a substantial population of stripped-envelope stars indeed exists, but has so far evaded detection because of observational biases and lack of large-scale systematic searches.

Abstract Copyright: © ESO 2018

Journal keyword(s): subdwarfs - binaries: close - supernovae: general

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 HD 2142 * 00 25 28.9744240531 -30 22 25.775911217   10.67 9.61     G8/K0(III) 7 0
2 * phi Per Be* 01 43 39.6379209 +50 41 19.432832 3.10 4.02 4.06 3.90 3.88 B1.5V:e-shell 542 0
3 HD 30353 sg* 04 48 53.3476426387 +43 16 32.094009964 8.05 8.22 7.76     A5Iap 135 0
4 HD 41335 Be* 06 04 13.5022124890 -06 42 32.225555101 4.31 5.14 5.21 5.13 5.09 B3/5Vnne 278 0
5 HD 45166 WR* 06 26 19.1550467867 +07 58 28.071465236 9.05 9.81 9.88     WRpec+B8V 72 1
6 HD 58978 Be* 07 26 59.4826767357 -23 05 09.683936209 4.51 5.45 5.56 7.05   B0.5IVe 216 0
7 V* BI Lyn No* 09 03 19.4275296265 +39 51 00.497866777   13.10 12.848     DB 23 0
8 LS 1922 SB* 10 47 56.8672551889 -59 08 53.132559788 11.04 11.24 10.44 10.30   OB+ 43 0
9 HD 320156 Em* 17 37 58.5049642529 -35 23 04.258134273 10.52 10.61 9.78 9.85   B4Ibe 65 0
10 V* NU Sgr LP* 18 49 19.7200831488 -22 44 50.129082730     13.04     ~ 2 0
11 * f01 Cyg Be* 20 59 49.5516391039 +47 31 15.378902421 3.77 4.71 4.75 4.62 4.63 B1.5Vnne 472 0
12 * 60 Cyg Be* 21 01 10.9277825432 +46 09 20.792180714 4.23 5.226 5.432     B1Ve 182 0

    Equat.    Gal    SGal    Ecl

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2021.07.29-16:16:59

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